scholarly journals Determination of 7B3 Residues in Cotton Plants by Liquid Chromatography/Mass Spectrometry

2009 ◽  
Vol 92 (1) ◽  
pp. 302-306 ◽  
Author(s):  
Xiao-Jing Yan ◽  
Xiao-Mei Liang ◽  
Yan-Jun Xu ◽  
Shu-Hui Jin ◽  
Dao-Quan Wang

Abstract A method was developed for the determination of 7B3 (12-propyloxyimino-1,15-pentadecanlactam), a novel macrolactam fungicide, by liquid chromatography/mass spectrometry (LC/MS) with positive electrospray ionization (ESI+). The method used a reversed-phase C18 column and acetonitrilewater (60 + 40, v/v) mobile phase. The quick, easy, cheap, effective, rugged, and safe method was used for extraction of 7B3 from cotton plants, which involved the extraction of 10 g homogenized sample with 10 mL acetonitrile, followed by the addition of 4 g anhydrous MgSO4 and 1.0 g NaCl. After centrifugation, 1 mL of the buffered acetonitrile extract was transferred into a tube containing 50 mg primary secondary amine sorbent and 100 mg anhydrous MgSO4. After shaking and centrifugation, the final extract was transferred to an autosampler vial for concurrent analysis by LC/MS. The results of 7B3 determined by LC/MS in the selective ion monitoring mode were linear, and the matrix effect of the method was evaluated. The average recoveries of 7B3 fortified at different levels were within 84.1100.2, and the relative standard deviations were <7.5 for all samples analyzed. The method limit of detection and the limit of quantitation values were 0.03 and 0.1 mg/kg, respectively. The proposed method was successfully applied to determine 7B3 residues in practical samples. This method is sensitive, accurate, reliable, simple, and safe.

2005 ◽  
Vol 88 (2) ◽  
pp. 645-653 ◽  
Author(s):  
Lisa Penney ◽  
Anderson Smith ◽  
Brent Coates ◽  
Arosha Wijewickreme

Abstract A new liquid chromatography/mass spectrometry (LC/MS) method is presented for the determination of chloramphenicol (CAP) residues in milk, eggs, chicken muscle and liver, and beef muscle and kidney. CAP is extracted from the samples with acetonitrile and defatted with hexane. The acetonitrile extracts are then evaporated, and residues are reconstituted in 10mM ammonium acetate–acetonitrile mobile phase and injected into the LC system. CAP is determined by reversed-phase chromatography using an Inertsil ODS-2 column and MS detection with negative ion electrospray ionization. Calibration curves were linear between 0.5–5.0 ng/g for all matrixes studied. The relative standard deviations for measurements by this method were generally <12%, and average recoveries ranged from 80 to 120%, depending on the matrix involved. The method detection limits of CAP ranged from 0.2 to 0.6 ng/g, which are comparable to previously reported results. The proposed method is rapid, simple, and specific, allowing a single analyst to easily prepare over 40 samples in a regular working day.


2005 ◽  
Vol 88 (2) ◽  
pp. 496-504 ◽  
Author(s):  
Lisa Penney ◽  
Caralee Bergeron ◽  
Brent Coates ◽  
Arosha Wijewickreme

Abstract A new liquid chromatography/mass spectrometry (LC/MS) method for the determination of dipyrone (DIP) and the DIP-related residues 4-formylaminoantipyrine (FAA), 4-aminoantipyrine (AA), and 4-methylaminoantipyrine (MAA) in milk, bovine muscle, and porcine muscle is presented. The analytes are extracted from the sample with methanol and defatted with hexane. The methanol extracts are then concentrated and injected into the LC system. Compounds are determined by reversed-phase LC using an Inertsil ODS-3 column with ammonium formate-acetonitrile mobile phase and MS detection using positive-ion electrospray ionization. Calibration curves were linear between 0.02 and 0.20 μg/g matrix equivalent concentration for FAA, AA, and MAA, and between 0.2 and 2.0 μg/g for DIP. The relative standard deviations for measurements by the proposed method were <11% for milk and porcine samples, with slightly greater variability for bovine samples. Average recoveries ranged from 82 to 128%, depending on the compound and matrix involved. The method detection limits of FAA, AA, and MAA were <0.02 μg/g for all matrixes tested, while those of DIP were <0.13 μg/g. The proposed method is rapid, simple, and specific, allowing a single analyst to easily prepare over 20 samples in a regular working day.


2007 ◽  
Vol 90 (1) ◽  
pp. 343-348 ◽  
Author(s):  
Ross A Potter ◽  
B Garth Burns ◽  
Jeffrey M van de Riet ◽  
David H North ◽  
Rozina Darvesh

Abstract A simple, robust method using liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the simultaneous determination of 17 sulfonamides sulfanilamide (SNL), sulfacetamide (SAA), sulfaguanidine (SGD), sulfapyridine (SPY), sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethoxazole (SOZ), sulfamoxole (SXL), sulfisoxazole (SXZ), sulfamethizole (SML), sulfamethazine (SMZ), sulfamethoxypyridazine (SMP), sulfamonomethoxine (SMM), sulfachloropyridazine (SCP), sulfaquinoxaline (SQX), and sulfadimethoxine (SDM) and 2 potentiators ormetoprim (OMP) and trimethoprim (TMP) in fish tissue has been developed. The analytes were extracted from homogenized fish tissue with wateracetonitrile (50 + 50). The extract was clarified by centrifugation and a portion defatted with hexane. The analytes were partitioned into chloroform and evaporated to dryness. The redissolved residue was applied to a C18 reversed-phase column with a wateracetonitrile (0.1% acetic acid) gradient. All of the compounds were completely separated and detected in <10 min at 30°C using LC/MS/MS. Standard curves were linear over the range of 0.02 to 5 ng injected. The limit of detection varied from 0.1 ng/g for SMZ and OMP to 0.9 ng/g for SXL and SOZ. Recoveries varied from 100% for SDM, SOZ, and SQX and 85% for SMR, OMP, and TMP to approximately 30% for SAA. Relative standard deviations for repeat analysis varied from 4% for SMZ and SCP to 23% for SAA.


Author(s):  
NARMADA PALNATI ◽  
NALINI KOTAPATI ◽  
GOPAL VAIDYANATHAN

Objective: The objective of the study was to develop and validate a simple, accurate, and sensitive liquid chromatography–mass spectrometry (LC–MS)/MS method for the determination of lapatinib a dual tyrosine kinase inhibitor in rat plasma using gefitinib as internal standard. Methods: An Inertsil ODS column (50 mm×4.6 mm×5 μm) was used for separation with isocratic elution of 10 mM ammonium formate-acetonitrile (5:95 v/v). Analyte and internal standard were extracted from 50 μl of plasma using tertiary butyl methyl ether followed by subsequent reconstitution in a mixture of water-acetonitrile. Results: The extraction recoveries were 95% and 98% for lapatinib and gefitinib, respectively. The lower limit of quantification was 5 ng/ml with a precision of 6.2% and accuracy of 108%. The response was found to be linear over the range of 5–1000 ng/ml with a correlation coefficient of 0.999. The intraday and interday precision expressed as relative standard deviation was <15%. Conclusion: This validated method was applied to the pharmacokinetic study in Wistar rats. The proposed bioanalytical LC–MS/MS method for lapatinib is a simple, sensitive, and accurate to quantify the concentrations in rat plasma.


2004 ◽  
Vol 87 (4) ◽  
pp. 961-964 ◽  
Author(s):  
Michael S Young ◽  
Kevin M Jenkins ◽  
Claude R Mallet

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.


1997 ◽  
Vol 80 (2) ◽  
pp. 392-400 ◽  
Author(s):  
Alexander J Krymtsky

Abstract A capillary electrophoresis (CE) method and an electrospray ionization (ESI) liquid chromatography/mass spectrometry (LC/MS) confirmatory method were developed to analyze 12 sulfonylurea herbicides and one sulfonamide (Flumetsulam) in runoff water. The water used for fortification was collected from a local marsh that contained high levels of potentially interfering compounds. Good recoveries and adequate sensitivity at the 0.2 ppb level (limit of quantitation) were obtained. A portion of the water was acidified and extracted with reversed- phase solid-phase extraction (SPE). Extracts were cleaned up with a tandem system consisting of a strong-anion exchange SPE cartridge stacked on an alumina SPE cartridge. CE/ultraviolet quantitation was achieved by capillary zone electrophoresis at pH 4.75 with 50 mM ammonium acetate buffer and an acetonitrile modifier. ESI LC/MS quantitation was achieved by using a time-scheduled selective-ion monitoring (positive mode) of the M+H ions for each compound. The extraction/cleanup procedure provided extracts such that in-source collision-induced dissociation gave product ions for confirmation at the 0.2 ppb fortification level.


2006 ◽  
Vol 89 (5) ◽  
pp. 1417-1424 ◽  
Author(s):  
Patricia J Nyman ◽  
Kim M Morehouse ◽  
Timothy P McNeal ◽  
Gracia A Perfetti ◽  
Gregory W Diachenko

Abstract A headspace gas chromatography/mass spectrometry method was developed and validated in-house for the determination of furan in foods. The method of standard additions with d4-furan as the internal standard was used to quantitate furan. The limit of detection and limit of quantitation (LOQ) values ranged from 0.2 and 0.6 ng/g, respectively, in apple juice to 0.9 and 2.9 ng/g, respectively, in peanut butter. Recoveries were obtained at 0.5, 1, 2, and 3 times the LOQ. At 1, 2, and 3 times the LOQ, the recoveries ranged from 89.4 to 108%, and the relative standard deviations ranged from 3.3 to 17.3% for all the matrixes. For apple juice, chicken broth, and infant formula, the averaged coefficients of determination from the linear regression analyses were &gt;0.99 with each food fortified at 0.5, 1, 2, and 3 times the LOQ. The coefficients of determination were &gt;0.99 for green beans and 0.96 for peanut butter with the foods fortified at 1, 2, and 3 times the LOQ. Within-laboratory precision was determined by comparing the amounts of furan found in 18 samples by 2 analysts on different days with different instruments. For most of the foods, the difference between the amounts found by each analyst was &lt;18%. The method was used to conduct a survey of &gt;300 foods. The furan levels found ranged from none detected to 174 ng/g.


2007 ◽  
Vol 90 (5) ◽  
pp. 1340-1345 ◽  
Author(s):  
Gianluca Dimartino

Abstract A convenient method is presented for determination of vitamin D in natural cheese, processed cheese, milk, cereals, noncarbonated soft drinks, and juice by liquid chromatography/mass spectrometry (LC/MS). Samples were saponified, extracted, evaporated, redissolved in acetonitrile, and injected into an LC-atmospheric pressure chemical ionization-MS system with no preparative chromatographic steps. Vitamin D was determined by selected ion monitoring. MS response was linear for vitamin D3 and its internal standard vitamin D2, and overall average recoveries ranged from 98 to 105. A blending experiment in which shredded vitamin D3-fortified cheddar was mixed with control nonfortified cheddar showed linearity. The limit of detection for vitamin D was 1.3 ng and the limit of quantitation was 3 ng. The method gave good accuracy and precision, with a standard deviation of 9.5 and relative standard deviation of 6.7. Results for vitamin D3 obtained with this method for different food matrixes, at different levels, were in agreement with those obtained with the reference LC/UV method currently used by many laboratories and derived from AOAC Official Method 982.29.


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