scholarly journals Determination of Residues of Alachlor and Related Herbicides in Crops by Liquid Chromatography with Electrochemical Detection

1997 ◽  
Vol 80 (5) ◽  
pp. 1104-1110 ◽  
Author(s):  
David A Nortrup
Keyword(s):  
Liquid Chromatography ◽  
Steam Distillation ◽  
Solid Phase ◽  
Base Hydrolysis ◽  
Phase Extraction ◽  
Test Portion ◽  
Strong Base ◽  
Relative Standard ◽  
Limit Of Quantitation

Abstract A method is described for determining residues of 3 acetamide herbicidesalachlor [2-chloro-N(2,6- diethylphenyl)-N(methoxymethyl)acetamide], acetochlor [2-chloro-N(2-ethyl-6-methylphenyl)-N (ethoxymethyl)acetamide), and butachlor [2-chloro-N(2,6-diethylphenyl)-N(butoxymethyl)- acetamide)by liquid chromatography (LC). Currently no published method determines metabolites from all 3 herbicides in crops. Strong-base hydrolysis after extraction of a test portion with water-acetonitrile results in the formation of 2,6- diethylaniline (DEA) and 2-(1-hydroxyethyl)-6-ethylaniline from alachlor metabolites, 2-ethyl-6-methylaniline and 2-(1-hydroxyethyl)-6-methylaniline from acetochlor metabolites, and DEA from butachlor. The anilines are isolated by steam distillation, partitioned with Supelclean ENVI-Chrom P solid-phase extraction columns, and methylated prior to LC analysis. The limit of quantitation of aniline moieties is about 0.01 ppm. Recoveries of 0.01- 0.40 ppm aniline moieties are generally 74-103%, with relative standard deviations of 2.2 to 14.0%.

scholarly journals Determination of Niacin in Infant Formula by Solid-Phase Extraction/Liquid Chromatography: Peer-Verified Method Performance–Interlaboratory Validation

2002 ◽  
Vol 85 (3) ◽  
pp. 654-664 ◽  
Author(s):  
Denis E LaCroix ◽  
Wayne R Wolf ◽  
G William Chase
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Reference Material ◽  
Infant Formula ◽  
Solid Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Interlaboratory Validation ◽  
Extraction Liquid

Abstract This paper reports the results of the interlaboratory peer validation study of AOAC Peer-Verified Method (PVM) 1:2000 for the determination of niacin in infant formula by solid-phase extraction/liquid chromatography. We have used a Data Quality Objectives (DQO) approach to address not only method variability and robustness but also accuracy of data through the use of an appropriate reference material in conjunction with the interlaboratory validation study. Our DQO included the following: (1) statistical agreement of analytical results and quantitative recovery between 2 collaborating laboratories; (2) the repeatability relative standard deviation (RSDr) values and the HORRAT (Horwitz ratio) obtained (1.07), which satisfied the criteria of the Horwitz “limits of acceptability” at the analyte level present; (3) validation of lack of interference; and (4) accuracy agreement within assigned values for a certified reference material. National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1846 Infant Formula, with a certified value of 63.3 ± 7.6 μg/g for niacin content, was used as a test material for collaborative study and accuracy assessment. Niacin values obtained by the originating laboratory were 59.7 ± 4.0 μg/g (95% confidence interval [CI] = 1.4 μg/g with a relative standard deviation [RSD] of 6.7%) and by the peer laboratory were 56.6 ± 6.6 μg/g (95% CI = 4.1 μg/g, with an RSD of 11.7%). Statistical evaluation using the means equivalence test showed that nicotinic acid values obtained by the peer laboratory were equivalent to those values obtained by the originating laboratory. Linear calibration curves and quantitative recovery were obtained. Integration of the PVM process with a readily available certified reference material gives the user confidence in the accuracy of the data generated by the method through traceability to the reference material used.

scholarly journals Simultaneous Determination of 23 Mycotoxins in Broiler Tissues by Solid Phase Extraction UHPLC-Q/Orbitrap High Resolution Mass Spectrometry

Separations ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 236
Author(s):  
Youyou Yang ◽  
Zhuolin He ◽  
Lei Mu ◽  
Yunfeng Xie ◽  
Liang Wang
Keyword(s):  
Mass Spectrometry ◽  
Solid Phase Extraction ◽  
Simultaneous Determination ◽  
Solid Phase ◽  
Harmful Effect ◽  
Phase Extraction ◽  
External Standard Method ◽  
Relative Standard ◽  
Limit Of Quantitation

Mycotoxins are a type of toxins harmful for not only animal but also human health. Cooccurrence of multi-mycotoxins could occur for food infected by several molds, producing multi-mycotoxins. It is necessary to develop corresponding determination methods, among which current mass spectrometry (MS) dominates. Currently, the accurate identification and quantitation of mycotoxins in complex matrices by MS with low resolution is still a challenge since false-positive results are typically obtained. Here, a method for the simultaneous determination of 23 mycotoxins in broiler tissues using ultra-high performance liquid chromatography-quadrupole/orbitrap HRMS was established. After the extraction by acetonitrile-water-formic acid (80:18:2, v/v/v), the purification by multifunctional purification solid phase extraction cartridges and the chromatographic separation on a C18 column, representative mycotoxins were determined by HRMS in full scan/data-dependent MS/MS acquisition mode. The quantitation was based on the external standard method. An MS/MS database of 23 mycotoxins was established to achieve qualitative screening and simultaneous quantification. Mycotoxins had a good linear relationship within a certain concentration range with correlation coefficients (r2) larger than 0.991 as well as the limit of quantitation of 1.80–300 μg/kg. The average recoveries at three different levels of low, medium and high fortification were 61–111% with relative standard deviations less than 13.5%. The method was fast, accurate, and suitable for the precise qualification of multiple mycotoxins in broiler tissues. 15 μg/kg zearalenone (ZEN) was detected in one liver sample among 30 samples from markets including chicken breast meat, liver, and gizzards. The result illustrated that the pollution of ZEN should not be neglected considering its harmful effect on the target organ of liver.

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.

On-Line Solid Phase Extraction Using the Prospekt-2 Coupled with a Liquid Chromatography/Tandem Mass Spectrometer for the Determination of Dextromethorphan, Dextrorphan and Guaifenesin in Human Plasma

2005 ◽  
Vol 11 (2) ◽  
pp. 199-208 ◽  
Author(s):  
Debbie L. Kuhlenbeck ◽  
Thomas H. Eichhold ◽  
Steven H. Hoke ◽  
Timothy R. Baker ◽  
Robert Mensen ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Human Plasma ◽  
Solid Phase ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass ◽  
On Line

An on-line liquid chromatography/tandem mass spectrometry (LC-MS/MS) procedure, using the Prospekt-2 system, was developed and used for the determination of the levels of the active ingredients of cough/cold medications in human plasma matrix. The experimental configuration allows direct plasma injection by performing on-line solid phase extraction (SPE) on small cartridge columns prior to elution of the analyte(s) onto the analytical column and subsequent MS/MS detection. The quantitative analysis of three analytes with differing polarities, dextromethorphan (DEX), dextrorphan (DET) and guaifenesin (GG) in human plasma presented a significant challenge. Using stable-isotope-labeled internal standards for each analyte, the Prospekt-2 on-line methodology was evaluated for sensitivity, suppression, accuracy, precision, linearity, analyst time, analysis time, cost, carryover and ease of use. The lower limit of quantitation for the on-line SPE procedure for DEX, DET and GG was 0.05, 0.05 and 5.0 ng mL−1, respectively, using a 0.1 mL sample volume. The linear range for DEX and DET was 0.05–50 ng mL−1 and was 5–5,000 ng mL−1 for GG. Accuracy and precision data for five different levels of QC samples were collected over three separate days. Accuracy ranged from 90% to 112% for all three analytes, while the precision, as measured by the %RSD, ranged from 1.5% to 16.0%.

scholarly journals Development and Validation of a High-Performance Liquid Chromatography Assay for Voriconazole

2003 ◽  
Vol 47 (7) ◽  
pp. 2348-2350 ◽  
Author(s):  
Gennethel J. Pennick ◽  
Martin Clark ◽  
Deanna A. Sutton ◽  
Michael G. Rinaldi
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
High Performance ◽  
Solid Phase ◽  
Phase Extraction ◽  
Extraction Technology ◽  
Limit Of Quantitation ◽  
Development And Validation

ABSTRACT An analytical method for the determination of voriconazole (UK-109,496; Pfizer) in plasma was developed and validated. The method utilizes solid-phase extraction technology and high-performance liquid chromatography. The lower limit of quantitation is 0.2 μg/ml, and the range of linearity tested was 0.2 to 10 μg/ml.

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 Single Laboratory Validation of a Method for the Determination of Hydroxymethylfurfural in Honey by Using Solid-Phase Extraction Cleanup and Liquid Chromatography

2005 ◽  
Vol 88 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Malcolm Driffield ◽  
Danny Chan ◽  
Roy Macarthur ◽  
Susan MacDonald ◽  
Paul Brereton ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Standard Uncertainty ◽  
Phase Extraction ◽  
Temperature Changes ◽  
Absorbance Detection ◽  
Relative Standard ◽  
Array Detection

Abstract A method is described for the determination of hydroxymethylfurfural (HMF) in honey. The method, which is based on solid-phase extraction cleanup followed by liquid chromatography (LC) with UV absorbance detection, was tested on a variety of different honey types: liquid, set, blended, filtered, crystalline, and comb honey. A sample of honey fortified with a known amount of HMF acted as an in-house reference material. LC with diode-array detection showed that the HMF peak did not contain any peaks of coeluting interfering species. Stability studies showed that honey samples should not be repeatedly frozen and thawed because the temperature changes caused a gradual increase in the HMF concentration. It was also shown that aqueous HMF standard solutions should be kept in the dark at 4°C to avoid degradation of the HMF. The method was internally validated, and the measurement uncertainty was estimated to be ±9.0 at 40 mg/kg, the legal limit. A comparison of the relative standard uncertainty with the Horwitz relative standard deviation showed that the method was suitable for its purpose and should be validated by a collaborative trial.

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

2005 ◽  
Vol 88 (3) ◽  
pp. 679-683 ◽  
Author(s):  
Matthew J Gramse ◽  
Paul E Jacobson
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Reversed Phase ◽  
Penicillin G ◽  
Phase Extraction ◽  
Solid Phase Extraction Cartridge ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for the determination of penicillin G in feeds. The method involves extraction of penicillin G with methanol, concentration under a stream of nitrogen, and cleanup using Phenomenex Strata-X solid-phase extraction cartridge. Analyte separation and quantification were achieved by gradient reversed-phase liquid chromatography and ultraviolet absorbance at 230 nm. Average spike recoveries for samples prepared at 3 spiking levels (25, 50, and 200 g/ton) were 96.3, 92.1, and 88.6%, respectively. The overall method precision at each of the 3 spiking levels was ≤5.39% relative standard deviation. The limits of detection and quantititation (g/ton formulation) were 3.89 and 13.0 g/ton, respectively.

scholarly journals Determination of Amoxicillin Residues in Animal Tissues by Solid-Phase Extraction and Liquid Chromatography with Fluorescence Detection

2000 ◽  
Vol 83 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Wenhong Luo ◽  
Catharina Y W Ang
Keyword(s):  
Liquid Chromatography ◽  
Sample Preparation ◽  
Solid Phase Extraction ◽  
Fluorescence Detection ◽  
Solid Phase ◽  
Fluorescence Analysis ◽  
Phase Extraction ◽  
Animal Tissues ◽  
Relative Standard

Abstract Trace levels of amoxicillin residues were determined in animal tissues by liquid chromatography (LC) with fluorescence detection. An improved solid-phase extraction (SPE) procedure requiring less flammable solvent (diethyl ether) was developed for sample preparation. Muscle samples of beef, pork, chicken, and tilapia were extracted with a phosphate buffer followed by the modified SPE procedure for cleanup and concentration prior to the LC–fluorescence analysis. Average recoveries of fortified amoxicillin at 5, 10, and 20 μg/kg ranged from 83.9 to 85.8% in beef, 86.1 to 88.1% in pork, 81.7 to 82.9% in chicken, and 92.5 to 95.4% in tilapia. Relative standard deviations were <4%.

scholarly journals Simultaneous Determination of 16 Sulfonamides in Honey by Liquid Chromatography/TandemMass Spectrometry

2005 ◽  
Vol 88 (5) ◽  
pp. 1304-1311 ◽  
Author(s):  
Guo-Fang Pang ◽  
Yan-Zhong Cao ◽  
Jin-Jie Zhang ◽  
Guang-Qun Jia ◽  
Chun-Lin Fan ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Solid Phase ◽  
Phosphoric Acid Solution ◽  
Tandem Mass ◽  
Phase Extraction ◽  
Chromatography Tandem Mass Spectrometry ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass ◽  
Oasis Hlb

Abstract A method is described for the determination of 16 sulfonamides in honey. Samples are dissolved in phosphoric acid solution (pH2), cleaned up with 2 solid-phase extraction (SPE) cartridges, an aromatic sulfonic cation-exchange cartridge and an Oasis HLB SPE cartridge, and analyzed both qualitatively and quantitatively by liquid chromatography/tandem mass spectrometry (LC/MS/MS) under the selected conditions. Without exception, calibration curves were linear (r = >0.995), when sulfamethizole was between 1.0 and 25.0 μg/kg; sulfacetamide, sulfapyridine, sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfamerazine, sulfisoxazole, sulfamonomethoxine, and sulfadoxine were between 2.0 and 50.0 μg/kg; sulfamethoxypyridazine, sulfadimethoxine, and sulfathiazole were between 4.0 and 100.0 μg/kg; sulfamethazine and sulfameter were between 8.0 and 200.0 μg/kg; and sulfaphenazole was between 12.0 and 300.0 μg/kg. Average recoveries at 4 fortification levels in the range of 1.0–300 μg/kg in honey were 70.9–102.5%, and relative standard deviations were 2.02–11.52%. The limits of quantitation for the 16 sulfonamides were between 1.0 and 12.0 μg/kg, with the LC/MS/MS method.

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