scholarly journals Development of EPA Method 535 for the Determination of Chloroacetanilide and Other Acetamide Herbicide Degradates in DrinkingWater by Solid-Phase Extraction and Liquid Chromatography/TandemMass Spectrometry

2006 ◽  
Vol 89 (1) ◽  
pp. 201-209 ◽  
Author(s):  
Jody A Shoemaker ◽  
Margarita V Bassett
Keyword(s):  
Drinking Water ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Environmental Protection Agency ◽  
Method Development ◽  
Solid Phase ◽  
Degradation Products ◽  
Internal Standard ◽  
Phase Extraction ◽  
Relative Standard

Abstract U.S. Environmental Protection Agency (EPA) Method 535 has been developed in order to provide a method for the analysis of Alachlor ESA and other acetanilide degradation products, which are listed on EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid-phase extraction with a nonporous graphitized carbon sorbent to extract the ethane sulfonic acid (ESA) and oxanilic acid degradates of propachlor, flufenacet, dimethenamid, alachlor, acetochlor, and metolachlor from finished drinking water matrixes. Separation and quantitation of the target analytes are achieved with liquid chromatography/tandem mass spectrometry. Dimethachlor ESA and butachlor ESA were chosen during the method development as the surrogate and internal standard. Drinking water samples were dechlorinated with ammonium chloride without adversely affecting the analyte recoveries. Typical mean recoveries of 92116% in deionized water and 89116% in ground water were observed with relative standard deviations of <5%.

scholarly journals Novel Chromatographic Separation and Carbon Solid-Phase Extraction of Acetanilide Herbicide Degradation Products

2002 ◽  
Vol 85 (6) ◽  
pp. 1331-1337 ◽  
Author(s):  
Jody A Shoemaker
Keyword(s):  
Drinking Water ◽  
Solid Phase Extraction ◽  
Chromatographic Separation ◽  
Solid Phase ◽  
Degradation Products ◽  
The United States ◽  
Negative Ion ◽  
Phase Extraction ◽  
Herbicide Degradation ◽  
Relative Standard

Abstract One acetamide and 5 acetanilide herbicides are currently registered for use in the United States. Over the past several years, ethanesulfonic acid (ESA) and oxanilic acid (OA) degradation products of these acetanilide/acetamide herbicides have been found in U.S. ground waters and surface waters. Alachlor ESA and other acetanilide degradation products are listed on the U.S. Environmental Protection Agency's (EPA) 1998 Drinking Water Contaminant Candidate List. Consequently, EPA is interested in obtaining national occurrence data for these contaminants in drinking water. EPA currently does not have a method for determining these acetanilide degradation products in drinking water; therefore, a research method is being developed using liquid chromatography/negative ion electrospray/mass spectrometry with solid-phase extraction (SPE). A novel chromatographic separation of the acetochlor/alachlor ESA and OA structural isomers was developed which uses an ammonium acetate–methanol gradient combined with heating the analytical column to 70°C. Twelve acetanilide degradates were extracted by SPE from 100 mL water samples using carbon cartridges with mean recoveries >90% and relative standard deviations ≤16%.

scholarly journals Solid-Phase Extraction and Cleanup Procedures for Determination of Acrylamide in Fried Potato Products by Liquid Chromatography/Mass Spectrometry

2004 ◽  
Vol 87 (4) ◽  
pp. 961-964 ◽  
Author(s):  
Michael S Young ◽  
Kevin M Jenkins ◽  
Claude R Mallet
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Internal Standard ◽  
Phase Extraction ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard

Abstract In response to recent discoveries of acrylamide in heated foods, a solid-phase extraction and cleanup protocol was developed for the determination of acrylamide in fried or baked potato samples by liquid chromatography/mass spectrometry (LC/MS). The analyte was extracted from the matrix by using 2M NaCl, and an aliquot of the initial extract was loaded onto a reversed-phase cartridge. After the analyte was eluted from the cartridge, the eluate was cleaned up on a mixed-mode cation-exchange cartridge. The eluate was then evaporated, and the residue was reconstituted in mobile phase before LC/MS analysis. Recoveries, based on the recovery of an added internal standard, ranged from 96 to 101% with relative standard deviations (RSDs) of 5–11%. The response was linear for a concentration range of 100–2000 ng/g with a coefficient of determination (R2)of 0.992 (n = 25). An interday study showed good accuracy and precision of the method over a 3-day period with a recovery of 98% and an RSD of 9.5% (n = 15). The analyses of 6 potato chip samples showed concentrations of incurred acrylamide ranging from 260 to 1500 ng/g.

scholarly journals Determination of Imazaquin Residues in Soil by Solid-Phase Extraction and High-Performance Liquid Chromatography

2007 ◽  
Vol 90 (2) ◽  
pp. 568-574 ◽  
Author(s):  
Chen Xuyan ◽  
Hu Jiye ◽  
Li Jianzhong
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Phase Extraction ◽  
Application Rates ◽  
Relative Standard ◽  
Strong Anion Exchange

Abstract A method has been developed for the quantitation of imazaquin residues in soil. The herbicide was extracted from soil with methanolwater (2 + 1, v/v) and cleaned up by strong anion-exchange solid-phase extraction cartridges. Analysis was performed by using high-performance liquid chromatography with ultraviolet detection. Average recoveries through the method ranged from 90.7 to 100.6%, with relative standard deviation equal to or lower than 6.6%. The limit of detection was estimated to be 0.0015 mg/kg, and the minimum quantitation concentration of imazaquin in soil was 0.005 mg/kg. This method was successfully applied to evaluate imazaquin residue levels in soil and its dissipation rates in a soybean field in the Xisanqi District of Beijing, People's Republic of China. The dissipation study showed that the half life of imazaquin in soil was 10.37 0.0135 days at 3 different application rates.

scholarly journals Multiresidue Determination of Pesticides in Drinking and Related Waters by Solid-Phase Extraction and Liquid Chromatography with Ultraviolet Detection: Interlaboratory Study

2002 ◽  
Vol 85 (2) ◽  
pp. 375-383 ◽  
Author(s):  
François van Hoof ◽  
Peter van Wiele ◽  
Françoise Acobas ◽  
Jean-Luc Guinamant ◽  
Auguste Bruchet ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Solid Phase Extraction ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Tap Water ◽  
Phase Extraction ◽  
Relative Standard ◽  
Styrene Divinylbenzene

Abstract As part of a project funded by the European Commission (EC) for the development and evaluation of multiresidue methods for analysis of drinking and related waters, 17 European laboratories evaluated a method using styrene–divinylbenzene copolymer solid-phase extraction followed by liquid chromatography with diode array detection. The main aim of the study was to evaluate whether the method meets the requirements of EC Drinking Water Directive 98/83 in terms of accuracy, precision, and detection limit for 21 pesticides according to the following requirements: limit of detection, ≤0.025 μg/L; accuracy expressed as recovery, between 75 and 125%; and precision expressed as repeatability relative standard deviation of the method, <12.5%, and as reproducibility relative standard deviation of the method, <25%. Analyses for unknown concentrations were performed with commercial bottled and tap waters. All laboratories were able to achieve detection limits of 0.01 μg/L for all pesticides except pirimicarb (0.02 μg/L). The criteria for repeatability were met for all compounds. Terbutryn in bottled water and carbendazim in tap water did not meet the criteria for reproducibility. In terms of accuracy, the method met the requirements for all pesticides in both matrixes, except for metamitron. However, several compounds (linuron, terbutryn, propazine, metobromuron, and isoproturon) showed recoveries slightly below 75%.

scholarly journals Determination of Tylosin in Feeds by Liquid Chromatography with Solid-Phase Extraction

2004 ◽  
Vol 87 (2) ◽  
pp. 341-345 ◽  
Author(s):  
Matthew J Gramse ◽  
Paul E Jacobson ◽  
James C Selkirk
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Column Temperature ◽  
Solid Phase Extraction Cartridge ◽  
Relative Standard ◽  
Phase Liquid

Abstract A method was developed for the determination of tylosin in feeds. The method involves extraction of tylosin with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex C18 solid-phase extraction cartridge. Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography and UV absorbance at 285 nm with a reference wavelength of 320 nm with column temperature of 45°C. Average spike recoveries for samples prepared at 4 spiking levels (22.7, 181, 907, and 1000 g/ton) were 111.0, 94.9, 96.2, and 98.6%, respectively. The overall method precision at each of the 4 spiking levels was ≤ 7.85% relative standard deviation. The limits of detection and quantitation (g/ton) were 2.16 and 7.20 g/ton, respectively.

Development of simultaneous determination of empagliflozin and metformin in human plasma using liquid chromatography–mass spectrometry and application to pharmacokinetics

2019 ◽  
Vol 26 (2) ◽  
pp. 117-130 ◽  
Author(s):  
Tejas Wattamwar ◽  
Ashish Mungantiwar ◽  
Supriya Halde ◽  
Nancy Pandita
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Human Plasma ◽  
Solid Phase ◽  
Internal Standard ◽  
Ion Source ◽  
Phase Extraction ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry

A rapid and sensitive liquid chromatography–mass spectrometry method was developed, optimized, and validated for simultaneous quantification of empagliflozin and metformin in human plasma using empagliflozin D4and metformin D6 as an internal standard. Analytes and internal standard were extracted from plasma by optimized solid-phase extraction technique using Strata X polymeric reverse phase (30 mg-1cc) solid-phase extraction cartridges. The prepared samples were chromatographed on Orosil C18 column (150 × 4.6 mm, 3 µ). Separation was done by pumping isocratic mobile phase consisting of methanol and 10 mM ammonium trifluoroacetate (90:10, v/v) in positive ion mode at a flow rate of 0.8 mL/min. The API 3200 liquid chromatography–mass spectrometry system having turbo ion spray as an ion source coupled with Shimadzu Prominence ultrafast liquid chromatography system was operated under the selected reaction monitoring mode. Turbo ion spray ionization was used for mass transition of m/z 468.070/355.100 and m/z 130.072/71.200 for empagliflozin and metformin, respectively. A method was successfully validated for concentration range of 10.09–5013.46 ng/mL for both the analytes and according to the United States Food and Drugs Administration guidelines. The linearity was found to be in the range of 10.09–403.46 ng/mL for empagliflozin and 25.44–5013.46 ng/mL for metformin. The limit of quantification was found to be 10.09 ng/mL for empagliflozin and 25.44 ng/mL for metformin. Intra- and inter-day/between batch precision determination for empagliflozin and metformin, expressed as coefficient of variation were within the acceptance limits and ranged below 13.16%. A short run time of 3.3 min allows analysis of more than 400 plasma samples per day. The developed method was successfully applied to fasting pharmacokinetic study in healthy human volunteers. Results of incurred sample re-analysis were within the acceptance range of ±20% of original value, for 97.2% of samples reanalyzed for empagliflozin and 100% of samples reanalyzed for metformin.

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