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Selected
papers from the latest issue:
Voltammetric determination of mercury(II)
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Chao Gao , Xing-Jiu Huang
Monitoring mercury provides a real challenge in analytical and environmental science, yet solutions are urgently needed due to the adverse effects of mercury on human health and the environment. Electrochemical techniques, more specifically voltammetric techniques, for determination of mercury(II) [Hg(II)] have inherent advantages. We review the state of the art in voltammetric determination of Hg(II) through quantitatively comparing different approaches classified according to the type of working electrode used. As much modern electroanalysis uses nanomaterials for the design of optimal electrode surfaces, this aspect is covered fully.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Chao Gao , Xing-Jiu Huang
Monitoring mercury provides a real challenge in analytical and environmental science, yet solutions are urgently needed due to the adverse effects of mercury on human health and the environment. Electrochemical techniques, more specifically voltammetric techniques, for determination of mercury(II) [Hg(II)] have inherent advantages. We review the state of the art in voltammetric determination of Hg(II) through quantitatively comparing different approaches classified according to the type of working electrode used. As much modern electroanalysis uses nanomaterials for the design of optimal electrode surfaces, this aspect is covered fully.
Advances for sensitive, rapid and selective extraction in different configurations of solid-phase microextraction
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Ali Mehdinia , Mohammad Ovais Aziz-Zanjani
Since its introduction in 1990s, different configurations of solid-phase microextraction (SPME) have been evaluated for different applications, and can be classified into the static and dynamic techniques. The current review briefly discusses the development of the techniques applied to reduce extraction time and/or to enhance extraction efficiency. It is also reviews selective microextraction techniques, such as molecularly-imprinted polymer, immunoaffinity, restricted access material and aptamer sol-gel SPME.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Ali Mehdinia , Mohammad Ovais Aziz-Zanjani
Since its introduction in 1990s, different configurations of solid-phase microextraction (SPME) have been evaluated for different applications, and can be classified into the static and dynamic techniques. The current review briefly discusses the development of the techniques applied to reduce extraction time and/or to enhance extraction efficiency. It is also reviews selective microextraction techniques, such as molecularly-imprinted polymer, immunoaffinity, restricted access material and aptamer sol-gel SPME.
Extraction and determination methodologies for benzotriazole UV stabilizers in personal-care products in environmental and biological samples
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): S. Montesdeoca-Esponda , T. Vega-Morales , Z. Sosa-Ferrera , J.J. Santana-Rodríguez
Benzotriazole UV stabilizers (BUVSs) are emerging contaminants that are mutagenic, toxic, pseudo-persistent, bioaccumulative and with significant estrogenic activity. However, the use of BUVSs in personal-care products (PCPs) is one of the primary ways that they enter the environment, often in “hot-spots” of discharge, such as wastewater-treatment plants (WWTPs). We present an overview of the current methods employed in the trace analysis of BUVSs in different types of environmental and biological samples. We compare and discuss potential advantages and disadvantages of each step involved in the analytical procedure.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): S. Montesdeoca-Esponda , T. Vega-Morales , Z. Sosa-Ferrera , J.J. Santana-Rodríguez
Benzotriazole UV stabilizers (BUVSs) are emerging contaminants that are mutagenic, toxic, pseudo-persistent, bioaccumulative and with significant estrogenic activity. However, the use of BUVSs in personal-care products (PCPs) is one of the primary ways that they enter the environment, often in “hot-spots” of discharge, such as wastewater-treatment plants (WWTPs). We present an overview of the current methods employed in the trace analysis of BUVSs in different types of environmental and biological samples. We compare and discuss potential advantages and disadvantages of each step involved in the analytical procedure.
Graphene as a new sorbent in analytical chemistry
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Rafal Sitko , Beata Zawisza , Ewa Malicka
In the past three years, we have seen intense interest grow in graphene (G) and graphene oxide (GO) as new sorbents in analytical chemistry. This article focuses on the adsorptive properties of G and GO and their application in preconcentrating organic compounds and trace-metal ions, including trace analysis of water, food, biological and environmental samples using chromatography and spectroscopy techniques. Some methods of modification or chemical functionalization of G and GO are also discussed. The article shows that G, GO and their derivatives or composites can be very attractive as sorbents due to their adsorption capacities being much higher than those of any of the currently reported sorbents.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Rafal Sitko , Beata Zawisza , Ewa Malicka
In the past three years, we have seen intense interest grow in graphene (G) and graphene oxide (GO) as new sorbents in analytical chemistry. This article focuses on the adsorptive properties of G and GO and their application in preconcentrating organic compounds and trace-metal ions, including trace analysis of water, food, biological and environmental samples using chromatography and spectroscopy techniques. Some methods of modification or chemical functionalization of G and GO are also discussed. The article shows that G, GO and their derivatives or composites can be very attractive as sorbents due to their adsorption capacities being much higher than those of any of the currently reported sorbents.
Recent progress of capillary electrophoresis in studying the speciation of actinides
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): A.R. Timerbaev , R.M. Timerbaev
This article reviews recent applications of the method for actinide-speciation analysis, with emphasis on using capillary-electrophoresis-separation schemes integrated with inductively coupled plasma mass-spectrometry detection. Also brought into focus are studies in which the speciation information acquired is complemented by relevant thermodynamic data on complexation of actinides with naturally-occurring ligands.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): A.R. Timerbaev , R.M. Timerbaev
This article reviews recent applications of the method for actinide-speciation analysis, with emphasis on using capillary-electrophoresis-separation schemes integrated with inductively coupled plasma mass-spectrometry detection. Also brought into focus are studies in which the speciation information acquired is complemented by relevant thermodynamic data on complexation of actinides with naturally-occurring ligands.
Analytical applications of chemiluminescence-detection systems assisted by magnetic microparticles and nanoparticles
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Mortaza Iranifam
Analytical applications of chemiluminescence detection systems based on magnetic microparticles and nanoparticles (MMP-CL and MNP-CL) have attracted growing interest in research and commercial fields. This article reviews the literature on the analytical applications of MMP-CL and MNP-CL systems, illustrated by different reaction strategies, such as immunoassay and hybridization labels in diverse fields (e.g., clinical and pharmaceutical, environmental or food analysis).
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Mortaza Iranifam
Analytical applications of chemiluminescence detection systems based on magnetic microparticles and nanoparticles (MMP-CL and MNP-CL) have attracted growing interest in research and commercial fields. This article reviews the literature on the analytical applications of MMP-CL and MNP-CL systems, illustrated by different reaction strategies, such as immunoassay and hybridization labels in diverse fields (e.g., clinical and pharmaceutical, environmental or food analysis).
Sampling uncertainty of wastewater monitoring estimated in a collaborative field trial
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Magda Cotman , Albin Pintar
This case study gives practical guidance on how uncertainty in monitoring programs can be reduced in wastewater sampling. Seventeen sampling teams took part in a trial. The monitoring consisted of both field and laboratory measurements. The variabilities between reported results of participants in the trial, expressed as coefficients of variation (CVs), were found to be 8.5% for chemical oxygen demand (COD), 9.5% for total suspended solids (TSS) and 14.5% for sulfate ion, respectively.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Magda Cotman , Albin Pintar
This case study gives practical guidance on how uncertainty in monitoring programs can be reduced in wastewater sampling. Seventeen sampling teams took part in a trial. The monitoring consisted of both field and laboratory measurements. The variabilities between reported results of participants in the trial, expressed as coefficients of variation (CVs), were found to be 8.5% for chemical oxygen demand (COD), 9.5% for total suspended solids (TSS) and 14.5% for sulfate ion, respectively.
Applications of nanomaterials in potentiometric sensors
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Tanji Yin , Wei Qin
Nanomaterials play an important role in the fabrication of chemosensors and biosensors, due to their unique physical and chemical properties, such as large surface area/volume ratio, good conductivity, excellent electrocatalytic activity and high mechanical strength. We review recent advances in the applications of these nanomaterials in potentiometric sensors. We highlight the development of stable solid-state polymeric membrane ion-selective electrodes (ISEs). We describe ISEs based on ionophore-modified nanomaterials. Also, we present highly-sensitive potentiometric biosensors based on nanomaterials.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Tanji Yin , Wei Qin
Nanomaterials play an important role in the fabrication of chemosensors and biosensors, due to their unique physical and chemical properties, such as large surface area/volume ratio, good conductivity, excellent electrocatalytic activity and high mechanical strength. We review recent advances in the applications of these nanomaterials in potentiometric sensors. We highlight the development of stable solid-state polymeric membrane ion-selective electrodes (ISEs). We describe ISEs based on ionophore-modified nanomaterials. Also, we present highly-sensitive potentiometric biosensors based on nanomaterials.
Ionic liquids in dispersive liquid-liquid microextraction
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): María J. Trujillo-Rodríguez , Priscilla Rocío-Bautista , Verónica Pino , Ana M. Afonso
In this review, we summarize the most recent analytical developments aimed at employing Ionic liquids (ILs) in dispersive liquid-liquid microextraction (DLLME). Four main operation modes can be distinguished: (1) conventional IL-DLLME; (2) temperature-controlled IL-DLLME; (3a) ultrasound-assisted, (3b) microwave-assisted or (3c) vortex-assisted IL-DLLME; and, (4) in-situ IL-DLLME. In these modes, the dispersive solvent can be an organic solvent, a surfactant, or a hydrophilic IL. In some cases, a dispersive solvent is not even necessary. We discuss practical applications of IL-DLLME to determine metals and organic compounds in a variety of samples.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): María J. Trujillo-Rodríguez , Priscilla Rocío-Bautista , Verónica Pino , Ana M. Afonso
In this review, we summarize the most recent analytical developments aimed at employing Ionic liquids (ILs) in dispersive liquid-liquid microextraction (DLLME). Four main operation modes can be distinguished: (1) conventional IL-DLLME; (2) temperature-controlled IL-DLLME; (3a) ultrasound-assisted, (3b) microwave-assisted or (3c) vortex-assisted IL-DLLME; and, (4) in-situ IL-DLLME. In these modes, the dispersive solvent can be an organic solvent, a surfactant, or a hydrophilic IL. In some cases, a dispersive solvent is not even necessary. We discuss practical applications of IL-DLLME to determine metals and organic compounds in a variety of samples.
Electrochemiluminescence quenching of tris(2,2′-bipyridyl)ruthenium
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Baomei Huang , Xibin Zhou , Zhonghua Xue , Xiaoquan Lu
Electrochemiluminescence (ECL) of tris(2,2′-bipyridyl)ruthenium [ Ru ( bpy ) 3 2 + ] has received considerable attention over broad applications due to its remarkably high sensitivity and extremely wide dynamic range. This review presents the state of ECL quenching of Ru ( bpy ) 3 2 + . After a brief introduction of the ECL of Ru ( bpy ) 3 2 + , we discuss in detail ECL-quenching co-reactants, the ECL-quenching mechanism and applications of ECL quenching coupled with capillary electrophoresis and flow-injection analysis.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Baomei Huang , Xibin Zhou , Zhonghua Xue , Xiaoquan Lu
Electrochemiluminescence (ECL) of tris(2,2′-bipyridyl)ruthenium [ Ru ( bpy ) 3 2 + ] has received considerable attention over broad applications due to its remarkably high sensitivity and extremely wide dynamic range. This review presents the state of ECL quenching of Ru ( bpy ) 3 2 + . After a brief introduction of the ECL of Ru ( bpy ) 3 2 + , we discuss in detail ECL-quenching co-reactants, the ECL-quenching mechanism and applications of ECL quenching coupled with capillary electrophoresis and flow-injection analysis.
Validation of a sampling procedure
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Małgorzata Bodnar , Jacek Namieśnik , Piotr Konieczka
Each step of the analytical procedure influences the final results in a significant way. In the majority of cases, the analytical procedure encompasses sampling because the analysis of the entire object (material) is usually impossible, so it is necessary to include the uncertainty related to sampling procedure in the uncertainty-budget calculations. This article describes two basic ways of estimating sampling uncertainty (i.e. experimental and modeling). There is also an example that shows how to estimate uncertainty using analysis of variance (ANOVA).
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Małgorzata Bodnar , Jacek Namieśnik , Piotr Konieczka
Each step of the analytical procedure influences the final results in a significant way. In the majority of cases, the analytical procedure encompasses sampling because the analysis of the entire object (material) is usually impossible, so it is necessary to include the uncertainty related to sampling procedure in the uncertainty-budget calculations. This article describes two basic ways of estimating sampling uncertainty (i.e. experimental and modeling). There is also an example that shows how to estimate uncertainty using analysis of variance (ANOVA).
First international comparative study of volatile fatty acids in aqueous samples by chromatographic techniques: Evaluating sources of error
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): F. Raposo , R. Borja , J.A. Cacho , J. Mumme , K. Orupõld , S. Esteves , J. Noguerol-Arias , S. Picard , A. Nielfa , P. Scherer , I. Wierinck , E. Aymerich , C. Cavinato , D.C. Rodriguez , N. García-Mancha , P.N.T. Lens , V. Fernández-Cegrí
This first international proficiency-testing scheme evaluated the analytical performance and the state of practice in measurement of volatile fatty acids in aqueous samples. Gas chromatography and high-performance liquid chromatography were used by 25 laboratories from 15 different countries. Two reference materials were selected for analysis. The performance of each laboratory was assessed by the internationally-accepted z-score. The overall performance was rather poor. Among the causes of poor analytical performance, human errors and inadequate calibration were probably the major problems encountered.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): F. Raposo , R. Borja , J.A. Cacho , J. Mumme , K. Orupõld , S. Esteves , J. Noguerol-Arias , S. Picard , A. Nielfa , P. Scherer , I. Wierinck , E. Aymerich , C. Cavinato , D.C. Rodriguez , N. García-Mancha , P.N.T. Lens , V. Fernández-Cegrí
This first international proficiency-testing scheme evaluated the analytical performance and the state of practice in measurement of volatile fatty acids in aqueous samples. Gas chromatography and high-performance liquid chromatography were used by 25 laboratories from 15 different countries. Two reference materials were selected for analysis. The performance of each laboratory was assessed by the internationally-accepted z-score. The overall performance was rather poor. Among the causes of poor analytical performance, human errors and inadequate calibration were probably the major problems encountered.
Surface development of molecularly imprinted polymer films to enhance sensing signals
18 September 2013,
08:10:14
Publication date: November
2013
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Piyush Sindhu Sharma , Marcin Dabrowski , Francis D’Souza , Wlodzimierz Kutner
Molecular imprinting of polymers is a well-established procedure for preparing artificial recognition units of chemical sensors. This procedure can produce materials of selectivity comparable to that of their biological counterparts. Deposition of a thin film of a molecularly imprinted polymer (MIP), playing a role of recognition unit, directly on surface of the transduction unit integrates these units to result in a chemical sensor. However, a smooth and continuous thin film of such a unit limits sensitivity of the devised chemosensor because of slow diffusion of an analyte through the film towards less accessible imprinted molecular cavities in the film bulk on the one hand and a low specific surface area on the other. Therefore, this area should be increased in a controllable way by developing the film surface. For that, macroporous MIP with large surface area, deposited directly on a transducer surface, effectively enhance signals in sensing applications. This review describes in detail a growing trend to prepare MIPs with a high (surface area)-to-volume ratio to enhance the sensing signal.
Source:TrAC Trends in Analytical Chemistry, Volume 51
Author(s): Piyush Sindhu Sharma , Marcin Dabrowski , Francis D’Souza , Wlodzimierz Kutner
Molecular imprinting of polymers is a well-established procedure for preparing artificial recognition units of chemical sensors. This procedure can produce materials of selectivity comparable to that of their biological counterparts. Deposition of a thin film of a molecularly imprinted polymer (MIP), playing a role of recognition unit, directly on surface of the transduction unit integrates these units to result in a chemical sensor. However, a smooth and continuous thin film of such a unit limits sensitivity of the devised chemosensor because of slow diffusion of an analyte through the film towards less accessible imprinted molecular cavities in the film bulk on the one hand and a low specific surface area on the other. Therefore, this area should be increased in a controllable way by developing the film surface. For that, macroporous MIP with large surface area, deposited directly on a transducer surface, effectively enhance signals in sensing applications. This review describes in detail a growing trend to prepare MIPs with a high (surface area)-to-volume ratio to enhance the sensing signal.
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