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:
Supercritical fluid extraction from spent coffee grounds and coffee husks: antioxidant activity and effect of operational variables on extract composition
17 November 2011, 23:48:10
Publication year: 2011
Source: Talanta, Available online 16 November 2011
Kátia S. Andrade, Ricardo T. Gonçalvez, Marcelo Maraschin, Rosa Maria Ribeiro-do-Valle, Julian Martínez, ...
The present study describes the chemical composition and the antioxidant activity of spent coffee grounds and coffee husks extracts, obtained by supercritical fluid extraction (SFE) with CO2and with CO2and co-solvent. In order to evaluate the high pressure method in terms of process yield, extract composition and antioxidant activity, low pressure methods, such as ultrasound (UE) and soxhlet (SOX) with different organic solvents, were also applied to obtain the extracts. The conditions for the SFE were: temperatures of 313.15 K, 323.15 K and 333.15 K and pressures from 100 to 300 bar. The SFE kinetics and the mathematical modeling of the overall extraction curves (OEC) were also investigated. The extracts obtained by LPE (low pressure extraction) with ethanol showed the best results for the global extraction yield (X0) when compared to SFE results. The best extraction yield was 15 ± 2% for spent coffee grounds with ethanol and 3.1 ± 04% for coffee husks. The antioxidant potential was evaluated by DPPH method, ABTS method and Folin-Ciocalteau method. The best antioxidant activity was showed by coffee husk extracts obtained by LPE. The quantification and the identification of the extracts were accomplished using HPLC analysis. The main compounds identified were caffeine and chlorogenic acid for the supercritical extracts from coffee husks.
Source: Talanta, Available online 16 November 2011
Kátia S. Andrade, Ricardo T. Gonçalvez, Marcelo Maraschin, Rosa Maria Ribeiro-do-Valle, Julian Martínez, ...
The present study describes the chemical composition and the antioxidant activity of spent coffee grounds and coffee husks extracts, obtained by supercritical fluid extraction (SFE) with CO2and with CO2and co-solvent. In order to evaluate the high pressure method in terms of process yield, extract composition and antioxidant activity, low pressure methods, such as ultrasound (UE) and soxhlet (SOX) with different organic solvents, were also applied to obtain the extracts. The conditions for the SFE were: temperatures of 313.15 K, 323.15 K and 333.15 K and pressures from 100 to 300 bar. The SFE kinetics and the mathematical modeling of the overall extraction curves (OEC) were also investigated. The extracts obtained by LPE (low pressure extraction) with ethanol showed the best results for the global extraction yield (X0) when compared to SFE results. The best extraction yield was 15 ± 2% for spent coffee grounds with ethanol and 3.1 ± 04% for coffee husks. The antioxidant potential was evaluated by DPPH method, ABTS method and Folin-Ciocalteau method. The best antioxidant activity was showed by coffee husk extracts obtained by LPE. The quantification and the identification of the extracts were accomplished using HPLC analysis. The main compounds identified were caffeine and chlorogenic acid for the supercritical extracts from coffee husks.
Highlights
► Coffee industry residues; ► Antioxidant sources; ► Increase the aggregated value of agroindustrial residues; ► The composition of coffee residue extracts suggests a high potential for industrial application; ► The supercritical technology was efficient for caffeine extraction from the residues.Determination Of Carbofuran In Surface Water And Biological Tissue By Sol-Gel Immunoaffinity Extraction And On-Line Preconcentration/Hplc/Uv Analysis
17 November 2011, 23:48:10
Publication year: 2011
Source: Talanta, Available online 16 November 2011
Luz E. Vera-Avila, Bani P. Márquez-Lira, Marcos Villanueva, Rosario Covarrubias, Gustavo Zelada, ...
A selective and simple analytical method for the trace level determination of carbofuran in complex environmental and biological samples was developed based on immunoaffinity extraction (IAE) followed by on-line preconcentration and HPLC/UV analysis of the purified extract. The immunosorbent for IAE was prepared by sol-gel encapsulation of monoclonal anti-carbofuran antibodies, and was fully characterized for capacity, repeatability, binding strength, binding kinetics and cross-reactivity. Method performance was evaluated with two different types of difficult samples: dam water and methanolic extracts of epithelial cervical-uterine tissue. Linear behavior and quantitative recoveries were obtained from the analysis of samples spiked with carbofuran at 0.2-4 ng/mL (dam water, 50 mL samples) and 10-40 ng/mL (biological tissue extract, 2 mL samples). RSD (n = 7) and detection limits were, respectively, 10.1% (spike 0.40 ng/mL) and 0.13 ng/mL for dam water; 8.5% (spike 20 ng/mL) and 5 ng/mL for the biological tissue extract. The excellent sample purification achieved with the IAE column allows precise and accurate determination of carbofuran in complex matrices, even when using non-selective UV detection in the chromatographic analysis.
Source: Talanta, Available online 16 November 2011
Luz E. Vera-Avila, Bani P. Márquez-Lira, Marcos Villanueva, Rosario Covarrubias, Gustavo Zelada, ...
A selective and simple analytical method for the trace level determination of carbofuran in complex environmental and biological samples was developed based on immunoaffinity extraction (IAE) followed by on-line preconcentration and HPLC/UV analysis of the purified extract. The immunosorbent for IAE was prepared by sol-gel encapsulation of monoclonal anti-carbofuran antibodies, and was fully characterized for capacity, repeatability, binding strength, binding kinetics and cross-reactivity. Method performance was evaluated with two different types of difficult samples: dam water and methanolic extracts of epithelial cervical-uterine tissue. Linear behavior and quantitative recoveries were obtained from the analysis of samples spiked with carbofuran at 0.2-4 ng/mL (dam water, 50 mL samples) and 10-40 ng/mL (biological tissue extract, 2 mL samples). RSD (n = 7) and detection limits were, respectively, 10.1% (spike 0.40 ng/mL) and 0.13 ng/mL for dam water; 8.5% (spike 20 ng/mL) and 5 ng/mL for the biological tissue extract. The excellent sample purification achieved with the IAE column allows precise and accurate determination of carbofuran in complex matrices, even when using non-selective UV detection in the chromatographic analysis.
Highlights
► An immunosorbent (IS) for carbofuran was prepared by the sol-gel technique ► Main IS properties were: high capacity, strong binding, selective, reproducible ► An immunoaffinity column was then used to extract carbofuran from complex samples ► Extract was further on-line preconcentrated and analyzed by SPE/HPLC/UV ► Good precision, accuracy and sensitivity were achieved with this methodNovel Furo[2,3–d] Pyrimidine Derivative as Fluorescent Chemosensor for HSO4
17 November 2011, 23:48:10
Publication year: 2011
Source: Talanta, Available online 16 November 2011
Weijian Xue, Lin Li, Qi Li, Anxin Wu
A class of novel heterocyclic compounds1a−1chas been designed and synthesized. And our initial discovery is that these compounds can effectively recognize HSO4. With the addition of HSO4, a new energy band appears at 360−390 nm in the absorption spectra. The emission spectrum (λex = 328 nm) undergoes an important change in its fluorescent effect in the presence of HSO4. All available data (absorption and emission) strongly support the formation of hydrogen−bonded complexes between1a−1cand HSO4.
Source: Talanta, Available online 16 November 2011
Weijian Xue, Lin Li, Qi Li, Anxin Wu
A class of novel heterocyclic compounds1a−1chas been designed and synthesized. And our initial discovery is that these compounds can effectively recognize HSO4. With the addition of HSO4, a new energy band appears at 360−390 nm in the absorption spectra. The emission spectrum (λex = 328 nm) undergoes an important change in its fluorescent effect in the presence of HSO4. All available data (absorption and emission) strongly support the formation of hydrogen−bonded complexes between1a−1cand HSO4.
An automated approach for analysis of Fourier Transform Infrared (FTIR) spectra of Edible Oils
17 November 2011, 23:48:10
Publication year: 2011
Source: Talanta, Available online 16 November 2011
Sim Siong Fong, Ting Woei
This paper reports a computational approach for analysis of FTIR spectra where peaks are detected, assigned and matched across samples to produce a peak table with rows corresponding to samples and columns to variables. The algorithm is applied on a dataset of 103 spectra of a broad range of edible oils for exploratory analysis and variable selection using Self Organising Maps (SOMs) and t-statistics, respectively. Analysis on the resultant peak table allows the underlying patterns and the discriminatory variables to be revealed. The algorithm is user-friendly; it involves a minimal number of tunable parameters and would be useful for analysis of a large and complicated FTIR dataset.
Source: Talanta, Available online 16 November 2011
Sim Siong Fong, Ting Woei
This paper reports a computational approach for analysis of FTIR spectra where peaks are detected, assigned and matched across samples to produce a peak table with rows corresponding to samples and columns to variables. The algorithm is applied on a dataset of 103 spectra of a broad range of edible oils for exploratory analysis and variable selection using Self Organising Maps (SOMs) and t-statistics, respectively. Analysis on the resultant peak table allows the underlying patterns and the discriminatory variables to be revealed. The algorithm is user-friendly; it involves a minimal number of tunable parameters and would be useful for analysis of a large and complicated FTIR dataset.
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