A new issue of this journal has just
been published. To see abstracts of the papers it contains (with links through
to the full papers) click here:
Selected
papers from the latest issue:
Application of ionic liquid for extraction and separation of bioactive compounds from plants
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Baokun Tang, Wentao Bi, Minglei Tian, Kyung Ho Row
In recent years, ionic liquids (ILs), as green and designer solvents, have accelerated research in analytical chemistry. This review highlights some of the unique properties of ILs and provides an overview of the preparation and application of IL or IL-based materials to extract bioactive compounds in plants. IL or IL-based materials in conjunction with liquid–liquid extraction (LLE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), high performance liquid chromatography (HPLC) and solid-phase extraction (SPE) analytical technologies etc., have been applied successfully to the extraction or separation of bioactive compounds from plants. This paper reviews the available data and references to examine the advantages of IL and IL-based materials in these applications. In addition, the main target compounds reviewed in this paper are bioactive compounds with multiple therapeutic effects and pharmacological activities. Based on the importance of the targets, this paper reviews the applications of ILs, IL-based materials or co-working with analytical technologies. The exploitation of new applications of ILs on the extraction of bioactive compounds from plant samples is expected to increase.
Source:Journal of Chromatography B, Volume 904
Baokun Tang, Wentao Bi, Minglei Tian, Kyung Ho Row
In recent years, ionic liquids (ILs), as green and designer solvents, have accelerated research in analytical chemistry. This review highlights some of the unique properties of ILs and provides an overview of the preparation and application of IL or IL-based materials to extract bioactive compounds in plants. IL or IL-based materials in conjunction with liquid–liquid extraction (LLE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), high performance liquid chromatography (HPLC) and solid-phase extraction (SPE) analytical technologies etc., have been applied successfully to the extraction or separation of bioactive compounds from plants. This paper reviews the available data and references to examine the advantages of IL and IL-based materials in these applications. In addition, the main target compounds reviewed in this paper are bioactive compounds with multiple therapeutic effects and pharmacological activities. Based on the importance of the targets, this paper reviews the applications of ILs, IL-based materials or co-working with analytical technologies. The exploitation of new applications of ILs on the extraction of bioactive compounds from plant samples is expected to increase.
Highlights
► The unique properties of ionic liquids were highlighted. ► IL or IL-based materials were used to extract bioactive compounds in plants. ► Advantages of IL and IL-based materials were in applications.HPTLC and reverse phase HPLC methods for the simultaneous quantification and in vitro screening of antioxidant potential of isolated sesquiterpenoids from the rhizomes of Cyperus rotundus
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
M. Priya Rani, K.P. Padmakumari
Three sesquiterpenoids solavetivone, aristolone and nootkatone were isolated from the acetone extract of Cyperus rotundus by silica gel column chromatography and identified by spectral studies. Solavetivone has been isolated for the first time from the species. Simple, sensitive and selective HPTLC and HPLC methods with ultraviolet detection (245nm) were developed and validated for the simultaneous quantification. HPTLC method was validated in terms of their linearity, LOD, LOQ, precision, accuracy and compared with RP-HPLC-UV method. Among the three sesquiterpenoids isolated, nootkatone possessed the highest radical scavenging potential (IC50 4.81μg/ml) followed by aristolone (IC50 5.28μg/ml) and solavetivone (IC50 6.82μg/ml) by DPPH radical scavenging assay. Total antioxidant activity against phosphomolybdenum reagent was also studied. The methods described in this paper were able to identify and quantify sesquiterpenoids from the complex mixtures of phytochemicals and could be extended to the marker based standardization of polyherbal formulations containing C. rotundus.
Source:Journal of Chromatography B, Volume 904
M. Priya Rani, K.P. Padmakumari
Three sesquiterpenoids solavetivone, aristolone and nootkatone were isolated from the acetone extract of Cyperus rotundus by silica gel column chromatography and identified by spectral studies. Solavetivone has been isolated for the first time from the species. Simple, sensitive and selective HPTLC and HPLC methods with ultraviolet detection (245nm) were developed and validated for the simultaneous quantification. HPTLC method was validated in terms of their linearity, LOD, LOQ, precision, accuracy and compared with RP-HPLC-UV method. Among the three sesquiterpenoids isolated, nootkatone possessed the highest radical scavenging potential (IC50 4.81μg/ml) followed by aristolone (IC50 5.28μg/ml) and solavetivone (IC50 6.82μg/ml) by DPPH radical scavenging assay. Total antioxidant activity against phosphomolybdenum reagent was also studied. The methods described in this paper were able to identify and quantify sesquiterpenoids from the complex mixtures of phytochemicals and could be extended to the marker based standardization of polyherbal formulations containing C. rotundus.
Highlights
► We identified three sesquiterpenoids, solavetivone, aristolone and nootkatone from the rhizomes of Cyperus rotundus. ► The sesquiterpenoid solavetivone, a vetispirane sesquiterpenoid, has been identified for the first time from the species. ► HPTLC and HPLC quantification was done for the isolated sesquiterpenoids. ► In vitro antioxidant and radical scavenging potential were screened. ► Nootkatone possessed the highest antioxidant potential among them.Determination of the thrombin inhibitor AZD0837 and its metabolites in human bile using mixed mode solid phase extraction and LC–MS/MS
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Kristina Dunér, Johan Hulthe, Mattias Tranberg
A method for the determination of AZD0837 and its two metabolites AR-H069927 and AR-H067637 in human bile was developed and validated. All three analytes and their stable isotope-labeled internal standards were isolated from bile using solid phase extraction on a mixed mode reversed phase/anion exchange column. Elution was done at high ionic strength with 0.125M ammoniumacetate in 50% methanol. The extraction recoveries were >75%. Due to the high concentration of AR-H067637 a portion of the extract was diluted before injection on to the LC column, while undiluted extract was directly injected for the analysis of AZD0837 and AR-H069927. Chromatographic separation of all three analytes was achieved in a single system utilizing a C18 column based on fused core particle technology at high flow rate. The two metabolites were eluted when a gradient from 30 to 57% methanol was applied while the more hydrophobic pro-drug, AZD0837, eluted during a steeper second gradient from 57 to 80% methanol with the ammonium acetate concentration and acetic acid concentration kept constant at 3.8mmol/L and 0.1%, respectively. The total cycle time was 3.2min. Detection was performed using positive electrospray ionization tandem mass spectrometry. The linearity range was 0.02–20μmol/L for AZD0837 and AR-H069927, and 1–1000μmol/L for AR-H067637. The repeatability and the overall precision were less than 15% (RSD) and the accuracy was within the interval 93–100%.
Source:Journal of Chromatography B, Volume 904
Kristina Dunér, Johan Hulthe, Mattias Tranberg
A method for the determination of AZD0837 and its two metabolites AR-H069927 and AR-H067637 in human bile was developed and validated. All three analytes and their stable isotope-labeled internal standards were isolated from bile using solid phase extraction on a mixed mode reversed phase/anion exchange column. Elution was done at high ionic strength with 0.125M ammoniumacetate in 50% methanol. The extraction recoveries were >75%. Due to the high concentration of AR-H067637 a portion of the extract was diluted before injection on to the LC column, while undiluted extract was directly injected for the analysis of AZD0837 and AR-H069927. Chromatographic separation of all three analytes was achieved in a single system utilizing a C18 column based on fused core particle technology at high flow rate. The two metabolites were eluted when a gradient from 30 to 57% methanol was applied while the more hydrophobic pro-drug, AZD0837, eluted during a steeper second gradient from 57 to 80% methanol with the ammonium acetate concentration and acetic acid concentration kept constant at 3.8mmol/L and 0.1%, respectively. The total cycle time was 3.2min. Detection was performed using positive electrospray ionization tandem mass spectrometry. The linearity range was 0.02–20μmol/L for AZD0837 and AR-H069927, and 1–1000μmol/L for AR-H067637. The repeatability and the overall precision were less than 15% (RSD) and the accuracy was within the interval 93–100%.
Highlights
► Simultaneous analysis of hydrophobic and hydrophilic analytes using mixed mode SPE. ► Bile differs from plasma affecting the choice of extraction procedure. ► The extraction method was fully automated. ► The cycle time was reduced by a high flow rate on a fused core LC column. ► The method was successfully validated for all three analytes.Development of a gas chromatographic method for the determination of Chlorpyrifos and its metabolite Chlorpyrifos-oxon in wine matrix
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Füsun Okçu Pelit, Levent Pelit, Hasan Ertaş, F. Nil Ertaş
A reliable method has been developed for the determination of Chlorpyrifos (CP) and its metabolite Chlorpyrifos-oxon (CPO) in wine sample using pulsed splitless technique coupled with gas chromatography by using electron capture detector. In this study, a quick, easy and cheap sample preparation method (QuEChERS) based on liquid extraction with acetonitrile, followed by dispersive solid phase extraction using primary secondary amine was tested for the separation and quantification of CP and CPO in wine samples. The accuracy of the developed method was tested upon recovery studies and it was calculated as (92.3±18.2)% for CP and (96.6±16.1)% for CPO. LOD and LOQ values of CP were found as 0.04 and 0.15ng/mL and 0.49 and 1.62ng/mL for CPO respectively. By using the pulsed splitless injection mode, the sensitivity of the determination of CP and its metabolite CPO in wine samples was improved compared to splitless technique. CP content of analyzed wine sample was found as 2.05±0.15ng/mL with a RSD of 7.6% and CPO content was found as 4.99±0.15ng/mL with a RSD of 3.0% (n =3). The expanded measurement uncertainties were calculated as 17% and 6% for CP and CPO, respectively.
Source:Journal of Chromatography B, Volume 904
Füsun Okçu Pelit, Levent Pelit, Hasan Ertaş, F. Nil Ertaş
A reliable method has been developed for the determination of Chlorpyrifos (CP) and its metabolite Chlorpyrifos-oxon (CPO) in wine sample using pulsed splitless technique coupled with gas chromatography by using electron capture detector. In this study, a quick, easy and cheap sample preparation method (QuEChERS) based on liquid extraction with acetonitrile, followed by dispersive solid phase extraction using primary secondary amine was tested for the separation and quantification of CP and CPO in wine samples. The accuracy of the developed method was tested upon recovery studies and it was calculated as (92.3±18.2)% for CP and (96.6±16.1)% for CPO. LOD and LOQ values of CP were found as 0.04 and 0.15ng/mL and 0.49 and 1.62ng/mL for CPO respectively. By using the pulsed splitless injection mode, the sensitivity of the determination of CP and its metabolite CPO in wine samples was improved compared to splitless technique. CP content of analyzed wine sample was found as 2.05±0.15ng/mL with a RSD of 7.6% and CPO content was found as 4.99±0.15ng/mL with a RSD of 3.0% (n =3). The expanded measurement uncertainties were calculated as 17% and 6% for CP and CPO, respectively.
Highlights
► Monitoring of pesticides with their metabolites is essential in food quality. ► This method is the first validated method to quantify CP and CPO in wine sample. ► The signal of CP and CPO was improved by pulsed splitless technique. ► Low detection limit for CPO compared to the literature. ► QuEChERS method was tested for the separation of CP and CPO.Quantification of acetaminophen and two of its metabolites in human plasma by ultra-high performance liquid chromatography–low and high resolution tandem mass spectrometry
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
David Tonoli, Emmanuel Varesio, Gérard Hopfgartner
The quantification of acetaminophen (APAP) and two of its metabolites, i.e. acetaminophen-glucuronide (APAP-GLUC) and acetaminophen-cysteine (APAP-CYS), is described in human plasma using ultra-high performance liquid chromatography coupled to a triple quadrupole linear ion trap mass spectrometer operating in the selected reaction monitoring (SRM/MS) mode and to a high resolution quadrupole time-of -flight mass spectrometer operating in the MS/MS (HR-SRM/MS) mode. Starting with a 50μL plasma aliquot, a generic sample preparation was performed using protein precipitation with methanol/ethanol. Both methods were found to be linear over 2.5 orders of magnitude. Similar performances to the SRM/MS assay were obtained for APAP, APAP-CYS and APAP-GLUC using high resolution-selected reaction monitoring mode with LLOQ of 20, 50 and 50ng/mL, respectively. For all analytes, precision was found to be better than 12% and accuracy in the range 90.3–109%. The present study demonstrates the ability of QqTOF platforms for accurate and precise quantification in MS/MS mode using short duty cycle with similar sensitivity to LC–SRM/MS. Additionally, as full scan data MSALL are available qualitative and quantitative information on metabolites can also be obtained in a single LC–MS run.
Source:Journal of Chromatography B, Volume 904
David Tonoli, Emmanuel Varesio, Gérard Hopfgartner
The quantification of acetaminophen (APAP) and two of its metabolites, i.e. acetaminophen-glucuronide (APAP-GLUC) and acetaminophen-cysteine (APAP-CYS), is described in human plasma using ultra-high performance liquid chromatography coupled to a triple quadrupole linear ion trap mass spectrometer operating in the selected reaction monitoring (SRM/MS) mode and to a high resolution quadrupole time-of -flight mass spectrometer operating in the MS/MS (HR-SRM/MS) mode. Starting with a 50μL plasma aliquot, a generic sample preparation was performed using protein precipitation with methanol/ethanol. Both methods were found to be linear over 2.5 orders of magnitude. Similar performances to the SRM/MS assay were obtained for APAP, APAP-CYS and APAP-GLUC using high resolution-selected reaction monitoring mode with LLOQ of 20, 50 and 50ng/mL, respectively. For all analytes, precision was found to be better than 12% and accuracy in the range 90.3–109%. The present study demonstrates the ability of QqTOF platforms for accurate and precise quantification in MS/MS mode using short duty cycle with similar sensitivity to LC–SRM/MS. Additionally, as full scan data MSALL are available qualitative and quantitative information on metabolites can also be obtained in a single LC–MS run.
Highlights
► The quantification of acetaminophen (APAP) and two of its metabolites by LC–MS/MS. ► Comparison of high-resolution MS/MS versus SRM/MS for quantitative analysis. ► QUAL/QUAN acquisition strategies for LC–MS.Simultaneous determination of active flavonoids and alkaloids of Tang-Min-Ling-Pill in rat plasma by liquid chromatography tandem mass spectrometry
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Yonghong Zhu, Ling Tong, Shuiping Zhou, He Sun, Kaishun Bi, Boli Zhang
A rapid, sensitive and reliable liquid chromatography tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of five active flavonoids (wogonin, chrysin, oroxylin A, naringenin, hesperetin) and four major alkaloids (berberine, coptisine, jatrorrhizine, palmatine) from Tang-Min-Ling-Pill in rat plasma. Plasma samples (100μL) were spiked with internal standards daidzein (for flavonoids) and tetrahydropalmatine (for alkaloids), acidified with HCl and extracted by liquid–liquid extraction with acetone. Chromatographic separation was performed on a Zorbax SB-C18 column with the mobile phase of water (containing 0.1% of formic acid)–acetonitrile (30:70, v/v) at a flow rate of 0.3mL/min in a run time of 7.0min. Detection was performed by multiple reaction monitoring mode using electrospray ionization in the positive ion mode. All analytes showed good linearity over the investigated concentration range (r >0.9900). The validated lower limit of quantification was 1.01ng/mL for wogonin and oroxylin A, 0.238ng/mL for chrysin, 1.01ng/mL for naringenin, 0.998ng/mL for hesperetin, 0.0505ng/mL for berberine, 0.0996ng/mL for coptisine, 0.0501ng/mL for jatrorrhizine, 0.0889ng/mL for palmatine, respectively. Intra- and inter-day precision (RSD%) was less than 15% and accuracy (RE%) ranged from −7.5% to 4.5%. The validated method was successfully applied to investigate the pharmacokinetics of the major flavonoids and alkaloids of Tang-Min-Ling-Pill after oral administration to rats.
Source:Journal of Chromatography B, Volume 904
Yonghong Zhu, Ling Tong, Shuiping Zhou, He Sun, Kaishun Bi, Boli Zhang
A rapid, sensitive and reliable liquid chromatography tandem mass spectrometry (LC–MS/MS) method was developed and validated for simultaneous determination of five active flavonoids (wogonin, chrysin, oroxylin A, naringenin, hesperetin) and four major alkaloids (berberine, coptisine, jatrorrhizine, palmatine) from Tang-Min-Ling-Pill in rat plasma. Plasma samples (100μL) were spiked with internal standards daidzein (for flavonoids) and tetrahydropalmatine (for alkaloids), acidified with HCl and extracted by liquid–liquid extraction with acetone. Chromatographic separation was performed on a Zorbax SB-C18 column with the mobile phase of water (containing 0.1% of formic acid)–acetonitrile (30:70, v/v) at a flow rate of 0.3mL/min in a run time of 7.0min. Detection was performed by multiple reaction monitoring mode using electrospray ionization in the positive ion mode. All analytes showed good linearity over the investigated concentration range (r >0.9900). The validated lower limit of quantification was 1.01ng/mL for wogonin and oroxylin A, 0.238ng/mL for chrysin, 1.01ng/mL for naringenin, 0.998ng/mL for hesperetin, 0.0505ng/mL for berberine, 0.0996ng/mL for coptisine, 0.0501ng/mL for jatrorrhizine, 0.0889ng/mL for palmatine, respectively. Intra- and inter-day precision (RSD%) was less than 15% and accuracy (RE%) ranged from −7.5% to 4.5%. The validated method was successfully applied to investigate the pharmacokinetics of the major flavonoids and alkaloids of Tang-Min-Ling-Pill after oral administration to rats.
Highlights
► Flavonoids exhibited biphasic pharmacokinetics in plasma concentration–time profiles. ► Wogonin, oroxylin A and chrysin were absorbed rapidly. ► Multiple plasma concentration peaks of the four alkaloids were observed. ► Pharmacokinetics of nine compounds were investigated in a run time of 7.0min.Simultaneous determination and pharmacokinetic study of six flavonoids from Fructus Sophorae extract in rat plasma by LC–MS/MS
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Lu Chang, Yanping Ren, Liang Cao, Yingguang Sun, Qian Sun, Ning Sheng, Lin Yuan, Xuran Zhi, Lantong Zhang
In this study, a new liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the determination of six flavonoids including sophoricoside, genistin, genistein, rutin, quercetin and kaempferol in rat plasma after oral administration of Fructus Sophorae extract using sulfamethalazole as internal standard (IS). The plasma samples were pretreated and extracted by liquid–liquid extraction. Chromatographic separation was accomplished on a C18 column with a simple linear gradient elution. The detection was accomplished by multiple-reaction monitoring (MRM) scanning after electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 431.1/267.9 for sophoricoside and genistin, 269.0/133.0 for genistein, 609.2/300.0 for rutin, 301.0/150.9 for quercetin, 284.9/93.0 for kaempferol and 252.0/155.9 for IS. The total run time was 8.0min. Full validation of the assay was implemented including specificity, linearity, accuracy, precision, recovery and matrix effect. This is the first report on determination of the major flavones in rat plasma after oral administration of Fructus Sophorae extract. The results provided a meaningful basis for the clinical application of this herb.
Source:Journal of Chromatography B, Volume 904
Lu Chang, Yanping Ren, Liang Cao, Yingguang Sun, Qian Sun, Ning Sheng, Lin Yuan, Xuran Zhi, Lantong Zhang
In this study, a new liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the determination of six flavonoids including sophoricoside, genistin, genistein, rutin, quercetin and kaempferol in rat plasma after oral administration of Fructus Sophorae extract using sulfamethalazole as internal standard (IS). The plasma samples were pretreated and extracted by liquid–liquid extraction. Chromatographic separation was accomplished on a C18 column with a simple linear gradient elution. The detection was accomplished by multiple-reaction monitoring (MRM) scanning after electrospray ionization (ESI) source operating in the negative ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 431.1/267.9 for sophoricoside and genistin, 269.0/133.0 for genistein, 609.2/300.0 for rutin, 301.0/150.9 for quercetin, 284.9/93.0 for kaempferol and 252.0/155.9 for IS. The total run time was 8.0min. Full validation of the assay was implemented including specificity, linearity, accuracy, precision, recovery and matrix effect. This is the first report on determination of the major flavones in rat plasma after oral administration of Fructus Sophorae extract. The results provided a meaningful basis for the clinical application of this herb.
Highlights
► We developed an LC–MS/MS method for the pharmacokinetic study of Fructus Sophorae. ► We also accomplished the separation of isomeride pair sophoricoside and genistin. ► The total run time was 8.0min by LC–ESI-MS.Simultaneously preparative purification of Huperzine A and Huperzine B from Huperzia serrata by macroporous resin and preparative high performance liquid chromatography
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Hongchao Zhang, Hao Liang, Pengqun Kuang, Qipeng Yuan, Yan Wang
Huperzine A (HupA) and Huperzine B (HupB) are natural alkaloids existed in Lycopodium plants. They both have potential clinical application for treating Alzheimer's Disease (AD). For the purpose of better utilizing the limited plant resources, a quick and low cost method to separate and purify HupA and HupB from Huperzia serrata (Thunb. ex Murray) was established in this paper. Low polarity macroporous resin SP850 was selected from eight kinds of resins during initial purification. Trifluoroacetic acid (TFA) was proved to be the best acid modifier reagent among all acids used in our experiment for improving separation. HupA and HupB were baseline separated on a C18 column by preparative high performance liquid chromatography (Preparative HPLC), the optimal gradient mobile phase system contained methanol increasing from 15% (v/v) to 35% (v/v) and 0.1% (v/v) TFA within the water. The purity of HupA and HupB obtained was 99.1% and 98.6%, respectively, and the total recovery for them was 83.0% and 81.8%, respectively.
Source:Journal of Chromatography B, Volume 904
Hongchao Zhang, Hao Liang, Pengqun Kuang, Qipeng Yuan, Yan Wang
Huperzine A (HupA) and Huperzine B (HupB) are natural alkaloids existed in Lycopodium plants. They both have potential clinical application for treating Alzheimer's Disease (AD). For the purpose of better utilizing the limited plant resources, a quick and low cost method to separate and purify HupA and HupB from Huperzia serrata (Thunb. ex Murray) was established in this paper. Low polarity macroporous resin SP850 was selected from eight kinds of resins during initial purification. Trifluoroacetic acid (TFA) was proved to be the best acid modifier reagent among all acids used in our experiment for improving separation. HupA and HupB were baseline separated on a C18 column by preparative high performance liquid chromatography (Preparative HPLC), the optimal gradient mobile phase system contained methanol increasing from 15% (v/v) to 35% (v/v) and 0.1% (v/v) TFA within the water. The purity of HupA and HupB obtained was 99.1% and 98.6%, respectively, and the total recovery for them was 83.0% and 81.8%, respectively.
Highlights
► We simultaneously purify HupA and HupB by reversed C18 column from Chinese herbs. ► We compare four kinds of acids of their influence to the separation of HupA and HupB. ► Macroporous resins were tested and SP850 was found best for initial purification. ► Trifluoroacetic acid performed best to eliminate the trailing problem.Simultaneous determination of multiple phthalate metabolites and bisphenol-A in human urine by liquid chromatography–tandem mass spectrometry
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Mei Chen, Lin Tao, Erin M. Collins, Christine Austin, Chensheng Lu
Phthalates and bisphenol A are environmental endocrine-disrupting chemicals used widely in common consumer products. There is increasing concern about human exposure to phthalates and bisphenol A due to the potential adverse effects related to the anti-androgenic activity of phthalates and estrogenic activity of bisphenol A. In assessing environmental exposure to phthalates and bisphenol A, it is essential to have a validated analytical method that can quantify trace concentrations of phthalate metabolites and bisphenol A in humans. In this study, we developed and validated an accurate, sensitive, and robust LC–MS/MS method to simultaneously quantify 5 phthalate monoester metabolites, including mono-methyl phthalate, mono-ethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, mono-2-ethylhexyl phthalate, and bisphenol A in human urine. In this method, the phthalate metabolites and bisphenol A, along with their isotope labeled internal standards, were extracted from 200μl of human urine using automated off-line solid phase extraction. The analytes were quantitatively determined using LC–MS/MS operated in negative electrospray ionization multiple reaction-monitoring mode. The limit of quantification was 0.3ng/ml for mono-methyl phthalate, mono-ethyl phthalate, mono-benzyl phthalate and bisphenol A, and 1ng/ml for mono-butyl phthalate and mono-2-ethylhexyl phthalate. The precision and accuracy were well within the acceptable 15% range. This validated method has been used successfully in assessing exposure to phthalates and bisphenol A in humans.
Source:Journal of Chromatography B, Volume 904
Mei Chen, Lin Tao, Erin M. Collins, Christine Austin, Chensheng Lu
Phthalates and bisphenol A are environmental endocrine-disrupting chemicals used widely in common consumer products. There is increasing concern about human exposure to phthalates and bisphenol A due to the potential adverse effects related to the anti-androgenic activity of phthalates and estrogenic activity of bisphenol A. In assessing environmental exposure to phthalates and bisphenol A, it is essential to have a validated analytical method that can quantify trace concentrations of phthalate metabolites and bisphenol A in humans. In this study, we developed and validated an accurate, sensitive, and robust LC–MS/MS method to simultaneously quantify 5 phthalate monoester metabolites, including mono-methyl phthalate, mono-ethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, mono-2-ethylhexyl phthalate, and bisphenol A in human urine. In this method, the phthalate metabolites and bisphenol A, along with their isotope labeled internal standards, were extracted from 200μl of human urine using automated off-line solid phase extraction. The analytes were quantitatively determined using LC–MS/MS operated in negative electrospray ionization multiple reaction-monitoring mode. The limit of quantification was 0.3ng/ml for mono-methyl phthalate, mono-ethyl phthalate, mono-benzyl phthalate and bisphenol A, and 1ng/ml for mono-butyl phthalate and mono-2-ethylhexyl phthalate. The precision and accuracy were well within the acceptable 15% range. This validated method has been used successfully in assessing exposure to phthalates and bisphenol A in humans.
Highlights
► A LC–MS/MS method for simultaneously analyzing 5 phthalate monoester metabolites and BPA in human urine is developed. ► The method was validated and demonstrated to be sensitive, accurate and precise using 200μl sample volume with a run time of 12min. ► This method has been used successfully in assessing the exposure of phthalates and BPA in 50 humans.Purification of plasmid DNA from clarified and non-clarified Escherichia coli lysates by berenil pseudo-affinity chromatography
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
C. Caramelo-Nunes, M.F. Gabriel, P. Almeida, J.C. Marcos, C.T. Tomaz
In this study, berenil was tested as a ligand, specifically to purify plasmids of different sizes pVAX1-LacZ (6.05Kbp) and pCAMBIA-1303 (12.361Kbp) from clarified Escherichia coli alkaline lysates. For this purpose, chromatographic experiments were performed using Sepharose derivatized with berenil. The results showed that both pDNA molecules are completely purified using lower amounts of salt in the eluent than those previously reported for other pseudo-affinity and hydrophobic interaction chromatography based processes. Total retention of all lysate components was achieved with 1.3M ammonium sulphate in the eluent buffer and pDNA elution was obtained by decreasing the salt concentration to 0.55M. All impurities were eluted after decreasing the concentration to 0M. The recovery yield for pCAMBIA-1303 (45%) was lower than that obtained for pVAX1-LacZ (85%), however the larger pDNA showed a higher purity level. Purification of pVAX1-LacZ was also performed using non-clarified E. coli process streams, replacing the clarification step with a second chromatographic run on the berenil-Sepharose. Using the same binding and elution conditions as before, a pure plasmid sample was obtained with a 33% yield and with all host impurity levels in accordance with the requirements established by the regulatory agencies. These results suggest that this chromatographic method is a promising alternative to purify pDNA for therapeutic use.
Source:Journal of Chromatography B, Volume 904
C. Caramelo-Nunes, M.F. Gabriel, P. Almeida, J.C. Marcos, C.T. Tomaz
In this study, berenil was tested as a ligand, specifically to purify plasmids of different sizes pVAX1-LacZ (6.05Kbp) and pCAMBIA-1303 (12.361Kbp) from clarified Escherichia coli alkaline lysates. For this purpose, chromatographic experiments were performed using Sepharose derivatized with berenil. The results showed that both pDNA molecules are completely purified using lower amounts of salt in the eluent than those previously reported for other pseudo-affinity and hydrophobic interaction chromatography based processes. Total retention of all lysate components was achieved with 1.3M ammonium sulphate in the eluent buffer and pDNA elution was obtained by decreasing the salt concentration to 0.55M. All impurities were eluted after decreasing the concentration to 0M. The recovery yield for pCAMBIA-1303 (45%) was lower than that obtained for pVAX1-LacZ (85%), however the larger pDNA showed a higher purity level. Purification of pVAX1-LacZ was also performed using non-clarified E. coli process streams, replacing the clarification step with a second chromatographic run on the berenil-Sepharose. Using the same binding and elution conditions as before, a pure plasmid sample was obtained with a 33% yield and with all host impurity levels in accordance with the requirements established by the regulatory agencies. These results suggest that this chromatographic method is a promising alternative to purify pDNA for therapeutic use.
Highlights
► Berenil pseudo-affinity chromatography to purify two different sized plasmids from clarified E. coli lysate. ► Optimized clarification of pDNA solutions. ► Plasmids are completely purified using small amounts of salt in the eluent. ► Impurity levels in accordance to FDA requirements. ► Promising alternative to purify pDNA for therapeutic use.Determination of celiprolol in human plasma using high performance liquid chromatography with fluorescence detection for clinical application
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Akiko Itohda, Kimiko Tsutsumi, Hiromitsu Imai, Miyuki Iwao, Tsutomu Kotegawa, Kyoichi Ohashi
A new method of analysis has been developed and validated for the determination of plasma celiprolol concentration. Plasma samples (1ml) were pre-purified by solid-phase extraction with Bond Elut® C18. The separation was achieved with XBridge™ C18 column (150mm×3.0mm i.d., 3.5μm) at 35°C using a mixture of acetonitrile and 10mM ammonium acetate buffer (pH 10.5) (34:66, v/v) under isocratic conditions at a flow rate of 0.4ml/min. The peak was detected using a fluorescence detector at excitation 250nm and emission 482nm. Retention times for the internal standard (acebutolol) and celiprolol were 4.2min and 6.3min, respectively. Calibration curves were linear over the range of 1.0–1000ng/ml (r >0.999), with a limit of quantification at 1.0ng/ml. Intra- and inter-assay precision (relative standard deviation) were less than 13.3% and the accuracy (relative error) was −5.1% to 11.5% at four different concentrations. This proposed method was successfully applied to a study of pharmacokinetic interactions between celiprolol and apple juice in humans.
Source:Journal of Chromatography B, Volume 904
Akiko Itohda, Kimiko Tsutsumi, Hiromitsu Imai, Miyuki Iwao, Tsutomu Kotegawa, Kyoichi Ohashi
A new method of analysis has been developed and validated for the determination of plasma celiprolol concentration. Plasma samples (1ml) were pre-purified by solid-phase extraction with Bond Elut® C18. The separation was achieved with XBridge™ C18 column (150mm×3.0mm i.d., 3.5μm) at 35°C using a mixture of acetonitrile and 10mM ammonium acetate buffer (pH 10.5) (34:66, v/v) under isocratic conditions at a flow rate of 0.4ml/min. The peak was detected using a fluorescence detector at excitation 250nm and emission 482nm. Retention times for the internal standard (acebutolol) and celiprolol were 4.2min and 6.3min, respectively. Calibration curves were linear over the range of 1.0–1000ng/ml (r >0.999), with a limit of quantification at 1.0ng/ml. Intra- and inter-assay precision (relative standard deviation) were less than 13.3% and the accuracy (relative error) was −5.1% to 11.5% at four different concentrations. This proposed method was successfully applied to a study of pharmacokinetic interactions between celiprolol and apple juice in humans.
Highlights
► A simple and sensitive HPLC method for determination of celiprolol in plasma was developed. ► The plasma samples were prepared by solid phase extraction. ► The calibration curves were linear over the range of 1–1000ng/ml (LLOQ, 1ng/ml). ► This validated method was successfully applied to an interaction study in humans.Posttranslational modifications of the insulin-like growth factor-binding protein 3 in patients with type 2 diabetes mellitus assessed by affinity chromatography
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Olgica Nedić, Dragana Lagundžin, Romana Masnikosa
Structural and ligand-binding properties of the insulin-like growth factor-binding protein (IGFBP)-3 in patients with poorly controlled diabetes mellitus type 2 were investigated using boronic acid- and lectin-affinity chromatography. IGFBP-3 species separated by chromatography were analyzed by immunoblotting and surface-enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS). Increased IGFBP-3 binding to boronic acid in patients was shown to be accompanied by the increased ligand-binding. Increased binding of IGFBP-3 forms to lectins from Sambucus nigra (SNA) and Canavalia ensiformis (ConA) in patients, on the other hand, was either not accompanied by altered ligand-binding (in the case of ConA) or it was reduced (in the case of SNA). Strong and opposite effects of glycation and additional sialylation on ligand binding qualify them as factors that may be involved in the regulation of the amount of free, physiologically active IGFs, and modulation of processes that accompany development and progression of diabetes. SELDI-TOF MS analysis revealed a fragment of 13.9kDa as representative for the non-glycosylated form of IGFBP-3, whereas a fragment of 28.0kDa profiled as typical for the glycosylated/glycated IGFBP-3 species. The same fragmentation pattern found in healthy persons and in patients indicates that the same degradation process predominantly occurs in both groups of individuals.
Source:Journal of Chromatography B, Volume 904
Olgica Nedić, Dragana Lagundžin, Romana Masnikosa
Structural and ligand-binding properties of the insulin-like growth factor-binding protein (IGFBP)-3 in patients with poorly controlled diabetes mellitus type 2 were investigated using boronic acid- and lectin-affinity chromatography. IGFBP-3 species separated by chromatography were analyzed by immunoblotting and surface-enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS). Increased IGFBP-3 binding to boronic acid in patients was shown to be accompanied by the increased ligand-binding. Increased binding of IGFBP-3 forms to lectins from Sambucus nigra (SNA) and Canavalia ensiformis (ConA) in patients, on the other hand, was either not accompanied by altered ligand-binding (in the case of ConA) or it was reduced (in the case of SNA). Strong and opposite effects of glycation and additional sialylation on ligand binding qualify them as factors that may be involved in the regulation of the amount of free, physiologically active IGFs, and modulation of processes that accompany development and progression of diabetes. SELDI-TOF MS analysis revealed a fragment of 13.9kDa as representative for the non-glycosylated form of IGFBP-3, whereas a fragment of 28.0kDa profiled as typical for the glycosylated/glycated IGFBP-3 species. The same fragmentation pattern found in healthy persons and in patients indicates that the same degradation process predominantly occurs in both groups of individuals.
Highlights
► IGFBP-3 in patients with diabetes mellitus is glycated and additionally sialylated. ► Glycation increases the affinity of IGFBP-3 for IGF-I, sialylation decreases it. ► Altered glycation/glycosylation may contribute to diabetic complications. ► Non-glycosylated and glycosylated/glycated IGFBP-3 undergo specific fragmentation.Comparison of amino acid derivatization reagents for LC–ESI-MS analysis. Introducing a novel phosphazene-based derivatization reagent
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Riin Rebane, Maarja-Liisa Oldekop, Koit Herodes
Amino acid analysis with high performance liquid chromatography with electrospray ionization mass spectrometry (LC–ESI-MS) is an emerging method. For more sensitive analysis, derivatization is used and next to commercially available derivatization reagents such as dansyl chloride (DNS), 9-fluorenylmethyl chloroformate (FMOC-Cl) and diethyl ethoxymethylenemalonate (DEEMM), new derivatization reagents are designed specially for LC–ESI-MS, like p-N,N,N-trimethylammonioanilyl N′-hydroxysuccinimidyl carbamate iodide (TAHS) which provides very low limits of detection. In this work, a novel phosphazene based derivatization reagent (FOSF) that provides comparable limits of quantitation (LoQ) to TAHS is introduced. Moreover, a thorough comparison between FOSF, TAHS, DNS, FMOC-Cl and DEEMM is carried out for 7 different amino acids – Arg, Asp, Gly, β-Ala, Pro, Trp and Phe. This is a first time that thorough comparison is carried out on the same instrument for amino acid derivatization reagents. Results on the same instrument for five amino acid derivatization reagents show that novel reagents are sensitive with LoQ values around 80fmol but have disadvantages such as problematic chromatographic separation. Next to novel reagents, DEEMM offers very good LoQ-s (average of 150fmol) and wide dynamic linear range.
Source:Journal of Chromatography B, Volume 904
Riin Rebane, Maarja-Liisa Oldekop, Koit Herodes
Amino acid analysis with high performance liquid chromatography with electrospray ionization mass spectrometry (LC–ESI-MS) is an emerging method. For more sensitive analysis, derivatization is used and next to commercially available derivatization reagents such as dansyl chloride (DNS), 9-fluorenylmethyl chloroformate (FMOC-Cl) and diethyl ethoxymethylenemalonate (DEEMM), new derivatization reagents are designed specially for LC–ESI-MS, like p-N,N,N-trimethylammonioanilyl N′-hydroxysuccinimidyl carbamate iodide (TAHS) which provides very low limits of detection. In this work, a novel phosphazene based derivatization reagent (FOSF) that provides comparable limits of quantitation (LoQ) to TAHS is introduced. Moreover, a thorough comparison between FOSF, TAHS, DNS, FMOC-Cl and DEEMM is carried out for 7 different amino acids – Arg, Asp, Gly, β-Ala, Pro, Trp and Phe. This is a first time that thorough comparison is carried out on the same instrument for amino acid derivatization reagents. Results on the same instrument for five amino acid derivatization reagents show that novel reagents are sensitive with LoQ values around 80fmol but have disadvantages such as problematic chromatographic separation. Next to novel reagents, DEEMM offers very good LoQ-s (average of 150fmol) and wide dynamic linear range.
Highlights
► TAHS and FOSF provide poorer chromatographic separation and smaller dynamic linear range. ► TAHS and FOSF provide lower LoD/LoQ values than DNS, FMOC-Cl and DEEMM. ► DNS, FMOC-Cl and DEEMM have good chromatographic separation and wide dynamic linear range. ► DEEMM is most optimal, with good LoQ values, chromatographic separation and wide linear range.Simultaneous quantification of niacin and its three main metabolites in human plasma by LC–MS/MS
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Man Liu, Dan Zhang, Xiaolin Wang, Lina Zhang, Jing Han, Man Yang, Xue Xiao, Yanan Zhang, Huichen Liu
A sensitive and specific LC–MS/MS method for the simultaneous quantification of niacin (NA) and its three main metabolites nicotinamide (NAM), nicotinuric acid (NUA) and N-methyl-2-pyridone-5-carboxamide (2-Pyr) in human plasma has been developed and validated. Plasma samples (200μL) were prepared by deproteinization with acetonitrile (500μL), then the supernatant after centrifugation was evaporated and reconstituted. Chromatography was performed on a phenomenex synergi hydro-RP column with an isocratic elution of methanol-0.1% formic acid (5:95, v/v). The full separation of all analytes was achieved within 9min. Multiple-reaction monitoring (MRM) using the fragmentation transitions of m/z 124.1→80.1, 123.1→80.0, 181.0→79.0 and 153.1→110.2 in positive electrospray ionization (ESI) mode was performed to quantify NA, NAM, NUA and 2-Pyr, respectively. The calibration curves were linear over the concentration range of 2.0–3000ng/mL for NA and NUA, 10.0–1600ng/mL for NAM and 50.0–5000ng/mL for 2-Pyr. This method has been validated in accordance with the US FDA guidelines for bioanalytical method development and applied to the determination of NA and its three main metabolites in Chinese subjects following a single oral dose of niacin extended-release and simvastatin 1000mg/20mg. In particular, because of the endogenous NAM and 2-Pyr in human plasma, the concentrations of NAM and 2-Pyr in human plasma after dosing were determined by subtracting blank values of them.
Source:Journal of Chromatography B, Volume 904
Man Liu, Dan Zhang, Xiaolin Wang, Lina Zhang, Jing Han, Man Yang, Xue Xiao, Yanan Zhang, Huichen Liu
A sensitive and specific LC–MS/MS method for the simultaneous quantification of niacin (NA) and its three main metabolites nicotinamide (NAM), nicotinuric acid (NUA) and N-methyl-2-pyridone-5-carboxamide (2-Pyr) in human plasma has been developed and validated. Plasma samples (200μL) were prepared by deproteinization with acetonitrile (500μL), then the supernatant after centrifugation was evaporated and reconstituted. Chromatography was performed on a phenomenex synergi hydro-RP column with an isocratic elution of methanol-0.1% formic acid (5:95, v/v). The full separation of all analytes was achieved within 9min. Multiple-reaction monitoring (MRM) using the fragmentation transitions of m/z 124.1→80.1, 123.1→80.0, 181.0→79.0 and 153.1→110.2 in positive electrospray ionization (ESI) mode was performed to quantify NA, NAM, NUA and 2-Pyr, respectively. The calibration curves were linear over the concentration range of 2.0–3000ng/mL for NA and NUA, 10.0–1600ng/mL for NAM and 50.0–5000ng/mL for 2-Pyr. This method has been validated in accordance with the US FDA guidelines for bioanalytical method development and applied to the determination of NA and its three main metabolites in Chinese subjects following a single oral dose of niacin extended-release and simvastatin 1000mg/20mg. In particular, because of the endogenous NAM and 2-Pyr in human plasma, the concentrations of NAM and 2-Pyr in human plasma after dosing were determined by subtracting blank values of them.
Highlights
► A LC–MS/MS method for simultaneous quantification of four analytes was developed. ► Simple protein precipitation was employed for the sample preparation. ► The concentrations of endogenous NAM and 2-Pyr were determined. ► The rLLOQ of endogenous NAM and 2-Pyr was calculated. ► The interferences from isotope effect or endogenous substances were avoided.Combining human periodontal ligament cell membrane chromatography with online HPLC/MS for screening osteoplastic active compounds from Coptidis Rhizoma
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Jin Liu, Jin Yang, Sicen Wang, Junyi Sun, Jianfeng Shi, Guozhou Rao, Ang Li, Jianzhong Gou
We have developed an online analytical method that combines human periodontal ligament cell membrane chromatography (hPDLC/CMC) with high-performance liquid chromatography and mass spectrometry (LC/MS) for recognizing and identifying osteoplastic active components from Coptidis Rhizoma. Retention fractions on hPDLC/CMC were enriched onto an enrichment column and the components were directly analyzed by combining a 10-port column switcher with an LC/MS system for separation and preliminary identification. Using simvastatin (SIM) as a positive control, berberine from Coptidis Rhizoma was identified as the active component which could act on the hPDLC. The MTT colorimetric assay, alkaline phosphatase (ALP) activity, and staining tests revealed that berberine could promote hPDLC growth, increase the secretion of ALP in the culture medium, and enhance the formation of mineralized nodule, thus it is a potential osteoplastic ingredient. This hPDLC/CMC–online-LC/MS method can be applied for screening active components acting on hPDLC from traditional Chinese medicines exemplified by Coptidis Rhizoma and will be of great utility in drug discovery using natural medicinal herbs as a source of leading compounds.
Source:Journal of Chromatography B, Volume 904
Jin Liu, Jin Yang, Sicen Wang, Junyi Sun, Jianfeng Shi, Guozhou Rao, Ang Li, Jianzhong Gou
We have developed an online analytical method that combines human periodontal ligament cell membrane chromatography (hPDLC/CMC) with high-performance liquid chromatography and mass spectrometry (LC/MS) for recognizing and identifying osteoplastic active components from Coptidis Rhizoma. Retention fractions on hPDLC/CMC were enriched onto an enrichment column and the components were directly analyzed by combining a 10-port column switcher with an LC/MS system for separation and preliminary identification. Using simvastatin (SIM) as a positive control, berberine from Coptidis Rhizoma was identified as the active component which could act on the hPDLC. The MTT colorimetric assay, alkaline phosphatase (ALP) activity, and staining tests revealed that berberine could promote hPDLC growth, increase the secretion of ALP in the culture medium, and enhance the formation of mineralized nodule, thus it is a potential osteoplastic ingredient. This hPDLC/CMC–online-LC/MS method can be applied for screening active components acting on hPDLC from traditional Chinese medicines exemplified by Coptidis Rhizoma and will be of great utility in drug discovery using natural medicinal herbs as a source of leading compounds.
Highlights
► We developed an hPDLC/CMC system combined with an HPLC/MS analytical method. ► Berberine from Coptidis Rhizoma was screened and identified as the active component which could act on the hPDLCs using the method. ► The effective of berberine were verified by MTT assay, and osteoplastic activity tests.Trace analysis of three antihistamines in human urine by on-line single drop liquid–liquid–liquid microextraction coupled to sweeping micellar electrokinetic chromatography and its application to pharmacokinetic study
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Wenhua Gao, Yunsheng Chen, Gaopan Chen, Jing Xi, Yaowen Chen, Jianying Yang, Ning Xu
A rapid and efficient dual preconcentration method of on-line single drop liquid–liquid–liquid microextraction (SD-LLLME) coupled to sweeping micellar electrokinetic chromatography (MEKC) was developed for trace analysis of three antihistamines (mizolastine, chlorpheniramine and pheniramine) in human urine. Three analytes were firstly extracted from donor phase (4mL urine sample) adjusted to alkaline condition (0.5M NaOH). The unionized analytes were subsequently extracted into a drop of n-octanol layered over the urine sample, and then into a microdrop of acceptor phase (100mM H3PO4) suspended from a capillary inlet. The enriched acceptor phase was on-line injected into capillary with a height difference and then analyzed directly by sweeping MEKC. Good linear relationships were obtained for all analytes in a range of 6.25×10−6 to 2.5×10−4 g/L with correlation coefficients (r) higher than 0.987. The proposed method achieved limits of detections (LOD) varied from 1.2×10−7 to 9.5×10−7 g/L based on a signal-to-noise of 3 (S/N=3) with 751- to 1372-fold increases in detection sensitivity for analytes, and it was successfully applied to the pharmacokinetic study of three antihistamines in human urine after an oral administration. The results demonstrated that this method was a promising combination for the rapid trace analysis of antihistamines in human urine with the advantages of operation simplicity, high enrichment factor and little solvent consumption.
Source:Journal of Chromatography B, Volume 904
Wenhua Gao, Yunsheng Chen, Gaopan Chen, Jing Xi, Yaowen Chen, Jianying Yang, Ning Xu
A rapid and efficient dual preconcentration method of on-line single drop liquid–liquid–liquid microextraction (SD-LLLME) coupled to sweeping micellar electrokinetic chromatography (MEKC) was developed for trace analysis of three antihistamines (mizolastine, chlorpheniramine and pheniramine) in human urine. Three analytes were firstly extracted from donor phase (4mL urine sample) adjusted to alkaline condition (0.5M NaOH). The unionized analytes were subsequently extracted into a drop of n-octanol layered over the urine sample, and then into a microdrop of acceptor phase (100mM H3PO4) suspended from a capillary inlet. The enriched acceptor phase was on-line injected into capillary with a height difference and then analyzed directly by sweeping MEKC. Good linear relationships were obtained for all analytes in a range of 6.25×10−6 to 2.5×10−4 g/L with correlation coefficients (r) higher than 0.987. The proposed method achieved limits of detections (LOD) varied from 1.2×10−7 to 9.5×10−7 g/L based on a signal-to-noise of 3 (S/N=3) with 751- to 1372-fold increases in detection sensitivity for analytes, and it was successfully applied to the pharmacokinetic study of three antihistamines in human urine after an oral administration. The results demonstrated that this method was a promising combination for the rapid trace analysis of antihistamines in human urine with the advantages of operation simplicity, high enrichment factor and little solvent consumption.
Highlights
► A dual preconcentration method combined in an on-line mode. ► Simple and rapid operation without time-consuming matrix-transfer steps. ► High enrichment efficiencies are got in trace analysis of analytes in urine matrix. ► The method is used for pharmacokinetic of chlorpheniramine in human urine.Rapid reversed-phase liquid chromatography separation of cyclolinopeptides with monolithic and microparticulate columns
24 August 2012,
09:08:17
Publication year:
2012
Source:Journal of Chromatography B, Volume 904
Clara M. Olivia, Peta-Gaye G. Burnett, Denis P. Okinyo-Owiti, Jianheng Shen, Martin J.T. Reaney
Three monolithic C18-bonded silica gel columns i.e. Chromolith® SpeedROD (CSR), Chromolith® Performance (CP), and Chromolith® High Resolution (CHR), MerckKGaA Darmstadt, Germany and two particle-based columns i.e. ZORBAX Eclipse XDB-C18 (ZEX), Agilent and POROS R1/20 (POR), Applied Biosystems were compared for their performance in separating a mixture of flaxseed cyclolinopeptides (CLs). Gradient mobile phases of acetonitrile and water were optimized for each column. The performance of CHR column in profiling CL standards, measured as the resolution of individual CL, selectivity, and peak asymmetry exceeded the performance of traditional particle-packed columns and the other monolithic columns. The profiling of CLs in aqueous methanolic flaxseed extract was optimized for high-throughput analysis. A total analysis time of 1.5min at a flow rate of 3.0mLmin−1 was achieved on a CSR column. Injection of over 2000 methanol extracts of flaxseed on a CSR column had no impact on backpressure or resolution of a standard CL mixture.
Source:Journal of Chromatography B, Volume 904
Clara M. Olivia, Peta-Gaye G. Burnett, Denis P. Okinyo-Owiti, Jianheng Shen, Martin J.T. Reaney
Three monolithic C18-bonded silica gel columns i.e. Chromolith® SpeedROD (CSR), Chromolith® Performance (CP), and Chromolith® High Resolution (CHR), MerckKGaA Darmstadt, Germany and two particle-based columns i.e. ZORBAX Eclipse XDB-C18 (ZEX), Agilent and POROS R1/20 (POR), Applied Biosystems were compared for their performance in separating a mixture of flaxseed cyclolinopeptides (CLs). Gradient mobile phases of acetonitrile and water were optimized for each column. The performance of CHR column in profiling CL standards, measured as the resolution of individual CL, selectivity, and peak asymmetry exceeded the performance of traditional particle-packed columns and the other monolithic columns. The profiling of CLs in aqueous methanolic flaxseed extract was optimized for high-throughput analysis. A total analysis time of 1.5min at a flow rate of 3.0mLmin−1 was achieved on a CSR column. Injection of over 2000 methanol extracts of flaxseed on a CSR column had no impact on backpressure or resolution of a standard CL mixture.
No comments:
Post a Comment