scholarly journals Comparison of Three Solid Phase Materials for the Extraction of Carboxylic Acids from River Water Followed by 2D GC × GC-TOFMS Determination

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
G. O. Bosire ◽  
J. C. Ngila ◽  
H. Parshotam
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Natural Organic Matter ◽  
Solid Phase ◽  
Cooling Water ◽  
Raw Water ◽  
Aliphatic Carboxylic Acid ◽  
Hydrophobic Nature ◽  
Relationship Of

The extraction and determination of aliphatic and aromatic carboxylic acids as well as their influence on the aromaticity and molecularity relationship of natural organic matter (NOM) in water are reported in this study. Three solid phase extraction (SPE) sorbents were used and their extraction efficiencies evaluated after chromatographic determinations (using gas chromatography with a time of flight mass spectrometer (GC × GC-TOFMS) and liquid chromatography with organic carbon detector (LC-OCD)). More than 42 carboxylic acids were identified in raw water from the Vaal River, which feeds the Lethabo Power Generation Station, South Africa, with cooling water. The aromatic carboxylic acid efficiency (28%) was achieved by using Strata™X SPE while the highest aliphatic carboxylic acid efficiency (92.08%) was achieved by silica SPE. The hydrophobic nature of NOM in water depends on the nature of organic compounds in water, whether aromatic or aliphatic. The LC-OCD was used to assess the hydrophobicity levels of NOM as a function of these carboxylic acids in cooling water. The LC-OCD results showed that the aromatic nature of NOM in SPE filtered water followed the order Silica>Strata X>C-18. From the results, the hydrophobicity degree of the samples depended on the type and number of carboxylic acids that were removed by the SPE cartridges.

scholarly journals Determination of higher carboxylic acids in snow samples using solid-phase extraction and LC/MS-TOF

2008 ◽  
Vol 392 (7-8) ◽  
pp. 1459-1470 ◽  
Author(s):  
Matthias Kippenberger ◽  
Richard Winterhalter ◽  
Geert K. Moortgat
Keyword(s):  
Solid Phase Extraction ◽  
Carboxylic Acids ◽  
Solid Phase ◽  
Phase Extraction ◽  
Snow Samples

Determination of Hydrophobic and Hydrophilic Fractions of Natural Organic Matter in Raw Water of Jalalieh and Tehranspars Water Treatment Plants (Tehran)

2007 ◽  
Vol 7 (18) ◽  
pp. 2651-2655 ◽  
Author(s):  
M.A. Zazouli ◽  
S. Nasseri . ◽  
A.H. Mahvi . ◽  
A.R. Mesdaghinia . ◽  
M. Younecian . ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Raw Water ◽  
Water Treatment Plants

Comparison of disinfection byproduct (DBP) formation from different UV technologies at bench scale

2002 ◽  
Vol 2 (5-6) ◽  
pp. 515-521 ◽  
Author(s):  
W. Liu ◽  
S.A. Andrews ◽  
J.R. Bolton ◽  
K.G. Linden ◽  
C. Sharpless ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carboxylic Acids ◽  
Natural Organic Matter ◽  
Uv Irradiation ◽  
Direct Action ◽  
Disinfection Byproduct ◽  
Pressure Medium ◽  
The Impact ◽  
As Effects

The impact of UV irradiation on disinfection byproduct (DBP) formation was investigated for low pressure, medium pressure and pulsed UV technologies using a broad range of UV doses. Four classes of DBPs (THMs, HAAs, aldehydes and carboxylic acids) were examined. This enabled the determination of effects resulting from the direct action of UV irradiation on natural organic matter (aldehydes, carboxylic acids) as well as effects on the ultimate formation of chlorinated DBPs (THMs and HAAs) from secondary chlorination. For doses of less than 1,000 mJ/cm2, UV irradiation did not affect THM and HAA formation in subsequent chlorination processes, however higher UV doses resulted in lower ultimate concentrations of THMs and HAAs. UV irradiation also resulted in the formation of aldehydes and carboxylic acids at UV doses above 500 mJ/cm2, compounds that are known to adversely effect drinking water biostability.

scholarly journals 4-t-Butylbenzylation of carboxylic acid for GC–MS analysis

2020 ◽  
Vol 2 (5) ◽  
Author(s):  
Shinji Tsunoi ◽  
Nao Yamamoto ◽  
Tomohiro Yasuhisa ◽  
Riko Akehi ◽  
Itaru Suzuki ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Water Samples ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Good Sensitivity ◽  
Good Reproducibility ◽  
Methyl Radical ◽  
Microwave Reactor

Abstract We report a 4-t-butylbenzyl derivatization for the analysis of carboxylic acids by GC–MS (EI). Carboxylic acids were analyzed as a 4-t-butylbenzyl ester after the derivatization with 4-t-butylbenzyl bromide. On the mass spectra of 4-t-butylbenzyl ester, [M-15]+ ions were observed with high intensity. These ions were tertiary benzyl cations generated by the elimination of a methyl radical from molecular ions. After optimization of the 4-t-butylbenzyl derivatization conditions using microwave reactor, we established a method for the determination of the carboxylic acids in water samples. The method showed good sensitivity and good reproducibility, and was successfully applied to the analysis of rain water samples.

scholarly journals Cost-Effective Detection of Perfluoroalkyl Carboxylic Acids with Gas Chromatography: Optimization of Derivatization Approaches and Method Validation

2019 ◽  
Vol 17 (1) ◽  
pp. 100 ◽  
Author(s):  
Zhen Li ◽  
Hongwei Sun
Keyword(s):  
Gas Chromatography ◽  
Surface Water ◽  
Solid Phase Extraction ◽  
Carboxylic Acids ◽  
Water Samples ◽  
Solid Phase ◽  
Cost Effective ◽  
Phase Extraction ◽  
Surface Water Samples

The reliable quantification of perfluoroalkyl carboxylic acids (PFCAs) in environmental samples like surface water by using gas chromatography (GC) remains challenging because the polar PFCAs call for derivatization before injection and problems involving the integration of sample pretreatment and derivatization procedures. Here we proposed a cost-effective method for the GC based determination of C4–C12 PFCAs in surface water samples by integrating solid phase extraction and PFCAs anilide derivatization. First, we assessed the performance of different PFCAs derivatization methods, namely esterification and amidation. Esterification was unable to derivatize C4–C6 PFCAs. On the contrary, amidation procedures by using 2,4-difluoroaniline (DFA) and N,N′-dicyclohexylcarbodiimide (DCC) could successfully transform all the PFCA analogs to produce anilide derivatives, which could be easily detected by GC. Then the reaction conditions in the amidation approach were further optimized by using orthogonal design experiments. After optimizing the instrumental parameters of GC, the limits of detection (LOD) of this derivatization method were determined to be 1.14–6.32 μg L−1. Finally, in order to establish an intact method for the quantification of PFCAs in surface water samples, solid phase extraction (SPE) was used for extraction and cleanup, which was further integrated with the subsequent amidation process. The SPE-amidation-GC method was validated for application, with good accuracy and precision reflected by the PFCAs recoveries and derivatization of triplicates. The method reported here could provide a promising and cost-effective alternative for the simultaneous determination of C4–C12 PFCAs in environmental water samples.

scholarly journals A Convenient and Sensitive LC-MS/MS Method for Simultaneous Determination of Carbadox- and Olaquindox-Related Residues in Swine Muscle and Liver Tissues

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Heying Zhang ◽  
Wei Qu ◽  
Yanfei Tao ◽  
Dongmei Chen ◽  
Shuyu Xie ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Simultaneous Determination ◽  
Solid Phase ◽  
Multiple Reaction Monitoring ◽  
Free Form ◽  
Anion Exchange Column ◽  
Tissue Samples ◽  
Metaphosphoric Acid ◽  
Liver Tissues

This paper presents a convenient and sensitive LC-MS/MS method for the simultaneous determination of carbadox and olaquindox residues, including desoxyolaquindox (DOLQ), desoxycarbadox (DCBX), quinoxaline-2-carboxylic acid (QCA), 3-methyl-quinoxaline-2-carboxylic acid (MQCA), and the glycine conjugates of QCA and MQCA (namely, QCA-glycine and MQCA-glycine, resp.) in swine muscle and liver tissues. Tissue samples were extracted with 2% metaphosphoric acid in 20% methanol and cleaned up by solid-phase extraction (SPE) on a mixed-mode anion-exchange column (Oasis MAX). Analysis was performed on a C18 column by detection with mass spectrometry in the multiple reaction monitoring (MRM) mode. The limits of detection (LODs) of the six analytes were determined to be 0.01 μg·kg−1 to 0.25 μg·kg−1, and the limits of quantification (LOQs) were 0.02 μg·kg−1 to 0.5 μg·kg−1. The total recoveries of the six analytes in all tissues were higher than 79.1% with the RSD% less than 9.2%. The developed method can determine the real residue level of QCA and MQCA, whether they are present in free form or as glycine conjugates in tissues, together with the carcinogenic desoxy metabolites DCBX and DOLQ with high recovery. Therefore, this method was suitable for routine analysis of residue control programmes and the residue depletion study of CBX and OLQ on swine.

Simultaneous Bioanalysis of Prodrug Oseltamivir and its Metabolite Oseltamivir Carboxylic Acid in Human Plasma by LC/MS/MS Method and its Application to Disposition Kinetics

2020 ◽  
Vol 16 (2) ◽  
pp. 143-152
Author(s):  
Dodda Sireesha ◽  
Makula Ajitha ◽  
Kandhagatta Raj Narayana
Keyword(s):  
Carboxylic Acid ◽  
Human Plasma ◽  
Solid Phase ◽  
Internal Standards ◽  
South Indian ◽  
Liquid Chromatography Tandem Mass ◽  
Incurred Sample Reanalysis ◽  
Oseltamivir Phosphate ◽  
Male Subjects

Introduction: A selective, sensitive, precise and rapid analytical method using liquid chromatography- tandem mass spectrometry (LC/MS/MS) for simultaneous determination of oseltamivir and oseltamivir carboxylic acid in plasma has been developed and validated, using oseltamivir-D5 and oseltamivir acid-D3 as internal standards. Methods: The analytes were extracted from 300μL of human plasma using solid phase extraction technique. A mixture of methanol and 0.1% formic acid (60:40, v/v) was used as mobile phase at a flow rate of 0.7mL/min, to separate the analytes on Zorbax SB-C18 (50x4.6mm, 3.5μm) analytical column. Results: The calibration curves obtained were linear over the concentration ranges of 0.5-200ng/mL and 2.0-800ng/mL for oseltamivir and oseltamivir carboxylic acid respectively. A run time of 2.5min makes it possible to analyze more than 350 plasma samples in a day, thereby increasing the productivity. Conclusion: The present method was applied successfully to a clinical pharmacokinetic study in South Indian male subjects with 75mg oseltamivir phosphate capsule under fasting conditions and the results were authenticated by incurred sample reanalysis.

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