scholarly journals Taurine Analysis in Milk and Infant Formulae by Liquid Chromatography: Collaborative Study

1997 ◽  
Vol 80 (4) ◽  
pp. 860-866 ◽  
Author(s):  
David C Woollard ◽  
Harvey E Indyk ◽  
G Angyal ◽  
J Borbon ◽  
W Chase ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Infant Formula ◽  
Lower Limit ◽  
Fluorescence Detection ◽  
Collaborative Study ◽  
Dansyl Derivative ◽  
Infant Formulae ◽  
Limit Of Determination ◽  
Liquid Chromatographic

Abstract A collaborative study was conducted on a liquid chromatographic (LC) method for determination of taurine in infant formula and milk powders. Twenty laboratories participated in the analysis of 8 blind duplicates over the range of approximately 3–60 mg/100 g sample. The method involved protein removal, conversion to the dansyl-derivative, and isocratic LC separation with UV and/or fluorescence detection. Following outlier treatment, overall mean RSDR has been estimated at 7.00% for sup. plemented products with a HORRAT value of 1.1. The poorer precision at endogenous levels establishes a lower limit of determination of about 5 mg/100 g. An overall mean RSDr:RSDR value of 0.7 for all products demonstrated acceptable performance.

Determination of Total Taurine in Pet Foods by Liquid Chromatography of the Dansyl Derivative: Collaborative Study

2000 ◽  
Vol 83 (4) ◽  
pp. 784-788 ◽  
Author(s):  
Kieran McCarthy ◽  
Claudia Hischenhuber ◽  
Neil Joyce ◽  
G Cherix ◽  
C Hischenhuber ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Collaborative Study ◽  
Gradient Elution ◽  
Taurine Concentration ◽  
Dansyl Derivative ◽  
Relative Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for the determination of total taurine in pet foods was evaluated in a collaborative study. Ten laboratories assayed 6 blind duplicate pairs of wet and dry pet foods. The taurine in the 6 sample pairs ranged from low (170 mg/kg) to high (2250 mg/kg) concentrations as is. Collaborators also assayed a sample of known taurine concentration for familiarization purposes. Samples were hydrolyzed to release bound taurine, which was subsequently converted to the dansyl derivative and quantitated by gradient-elution LC with fluorescence detection. Repeatability relative standard deviations, RSDr, ranged from 3.2 to 10.0%; reproducibility relative standard deviations, RSDR, ranged from 6.1 to 16.1%. The method has been adopted Official First Action status by AOAC INTERNATIONAL.

scholarly journals Determination of Vitamins A (Retinol) and E (alpha-Tocopherol) in Foods by Liquid Chromatography: Collaborative Study

2002 ◽  
Vol 85 (2) ◽  
pp. 424-434 ◽  
Author(s):  
Jonathan W DeVries ◽  
Karlene R Silvera ◽  
S Al-Hasani ◽  
J Alfiere ◽  
C Berge ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Water Solution ◽  
Collaborative Study ◽  
Alpha Tocopherol ◽  
Food Matrix ◽  
Peak Areas ◽  
Liquid Chromatographic

Abstract A collaborative study was conducted for the determination of vitamins A and E. Existing AOAC liquid chromatographic (LC) methods are suited for specific vitamins A and E analytical applications. This method differs from existing methods in that it can be used to assay samples in all 9 sectors of the food matrix. Standards and test samples are saponified in basic ethanol–water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters and tocopherol esters to retinol and tocopherol, respectively. Retinol and alpha-tocopherol are quantitated on separate LC systems, using UV detection at 313 or 328 nm for retinol, and fluorescence detection (excitation 290 nm, emission 330 nm) for alpha-tocopherol. Vitamin concentrations are calculated by comparison of the peak heights or peak areas of vitamins in test samples with those of standards.

Determination of Diacetyl in Butter as 2,3-Diaminonaphthalene Derivative, Using a Fluorometric Procedure or Reverse Phase Liquid Chromatography with Fluorescence Detection

1988 ◽  
Vol 71 (3) ◽  
pp. 462-465
Author(s):  
Pietro Damiani ◽  
Giovanni Burini
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
The Other ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Fluorescence Characteristics ◽  
Chromatographic Procedure ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Two procedures, one fluorometric and the other reverse phase liquid chromatographic, for determination of a derivative of diacetyl are described. Exploratory work on diacetyl standard solutions to establish the best conditions for the derivatization with 2,3-diaminonaphthalene (DAN) to yield 2,3-dimethylbenzo[g]-quinoxaline (DMBQ) is discussed, as well as the fluorescence characteristics of the DMBQ derivative. Diacetyl was determined in 10 commercial butter samples by the proposed procedures and by other known methods (determination of o-phenylenediamine and 3,3-diaminobenzidinederivatives). Recoveries from butter samples spiked with known amounts of diacetyl ranged from 96.9 to 101.8% (with CVs ranging from 0.3 to 2.1%) for the fluorometric procedure and from 96.9 to 102.7% (with CVs ranging from 0.5 to 2.4%) for the chromatographic procedure. These results agree well with those obtained with o-phenylenediamine and 3,3-diaminobenzidine methods on the same butter samples. The proposed methods have the advantages of improved detectability and specificity.

scholarly journals Determination of Halofuginone and Amprolium in Chicken Muscle and Egg by Liquid Chromatography

2001 ◽  
Vol 84 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Yuzo Yamamoto ◽  
Fusao Kondo
Keyword(s):  
Lower Limit ◽  
Solid Phase ◽  
Lauryl Sulfate ◽  
Ultraviolet Detection ◽  
Chicken Egg ◽  
Chicken Muscle ◽  
Limit Of Determination ◽  
Cleanup Procedure ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed for simultaneous measurement of halofuginone (HFN) and amprolium (APL) in chicken muscle and egg. HFN and APL were extracted from chicken muscle and egg with acetonitrile. In chicken egg, they were partially purified by solid-phase extraction (SPE) to separate them from impurities. The LC separation was performed on a 4.6 mm id × 250 mm TSK-gel ODS-80TM column using acetonitrile–McIlvaine buffer, pH 3.4, containing 0.01M sodium lauryl sulfate (42 + 58) as the mobile phase. Ultraviolet detection of HFN and APL was performed at wavelengths of 242 and 265 nm, respectively. Recoveries of HFN and APL from chicken muscle spiked at 0.5 μg/g were 74.8 ± 17.7 and 94.2 ± 5.0%, respectively (mean ± standard deviation [SD], n = 10). In chicken muscle, the lower limit of determination for both APL and HFN was 0.03 μg/g. Recoveries of HFN and APL from chicken egg spiked at 0.5 μg/g by a cleanup procedure using SPE were 54.6 ± 3.4 and 85.0 ± 2.4%, respectively (mean ± SD, n = 5). In chicken egg, the lower limit of determination for both APL and HFN was 0.04 μg/g.

Determination of Cymiazole Residues in Honey by Liquid Chromatography

1993 ◽  
Vol 76 (1) ◽  
pp. 92-94 ◽  
Author(s):  
Paolo Cabras ◽  
Marinella Melis ◽  
Lorenzo Spanedda
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Analysis ◽  
Mobile Phase ◽  
Chromatographic Method ◽  
Reversed Phase ◽  
Limit Of Determination ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic ◽  
Control Samples

Abstract A liquid chromatographic method is described for the determination of cymiazole residues in honey. This acaricide is determined on a reversed-phase (C18) column, with a CH3CN-O.OOIN HCI-NaCI mixture (950 mL + 50 mL + 0.3 g/L) as the mobile phase, and UV detection at 265 nm. Cymiazole is extracted with n-hexane from aqueous alkalinized (pH 9) honey solutions. No further cleanup of the honey extract was required before chromatographic analysis. Recoveries on control samples fortified with 0.01,0.10, and 1.00 ppm cymiazole ranged from 92 to 102%. The limit of determination was 0.01 ppm.

Determination of iV-Methylcarbamate Pesticides in Liver by Liquid Chromatography

1989 ◽  
Vol 72 (4) ◽  
pp. 586-592 ◽  
Author(s):  
Sher M Ali
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Fluorescence Detection ◽  
Methylene Chloride ◽  
Gel Permeation Chromatography ◽  
Purification Technique ◽  
Coefficients Of Variation ◽  
Gel Permeation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method using a 2-step purification technique for the simultaneous determination of 10 carbamates in bovine, swine, and duck livers has been developed. Carbamates are extracted from liver samples with methylene chloride. After evaporation, the residues from the extract are dissolved in methylene chloride- cyclohexane (1 + 1) and cleaned up by gel permeation chromatography. The eluate containing carbamate residues is evaporated to dryness, reconstituted in methylene chloride, further purified by passing it through an aminopropyl Bond Elut extraction cartridge, and analyzed by liquid chromatography using post-column derivatization with orthophthalaldehyde and fluorescence detection. Excitation and emission are set at 340 and 418 nm, respectively. Liver samples for beef, pork, and duck were fortified with 5, 10, and 20 ppb of mixed carbamate standards. The average of 10 recoveries of 10 carbamates at all 3 levels of fortification was greater than 80% with coefficients of variation less than 17%.

Determination of Cinnamyl Anthranilate in Perfume, Cologne, and Toilet Water by Liquid Chromatography with Fluorescence Detection

1987 ◽  
Vol 70 (6) ◽  
pp. 958-960
Author(s):  
Francois X Demers ◽  
Ronald L Yates ◽  
Henry M Davis
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Fluorescence Detection ◽  
Chromatographic Method ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method with fluorescence detection was developed for the determination of cinnamyl anthranilate in perfumes and other fragrance compositions. The method was evaluated by conducting recovery studies of 10 different commercial fragrance compositions to which cinnamyl anthranilate had been added at levels of 0.1, 0.5, and 1.0 mg/mL. Recoveries ranged from 91 to 103% with a mean of 97% and a standard deviation of ±3.3%.

Determination of Vitamin A (Retinol) in Infant Formula and Adult Nutritionals by Liquid Chromatography: First Action 2011.15

2012 ◽  
Vol 95 (2) ◽  
pp. 322-328
Author(s):  
Jonathan W DeVries ◽  
Karlene R Silvera ◽  
Elliot McSherry ◽  
Dawn Dowell
Keyword(s):  
Liquid Chromatography ◽  
Vitamin A ◽  
Infant Formula ◽  
Collaborative Study ◽  
Alpha Tocopherol ◽  
Powdered Infant Formula ◽  
Food Matrix ◽  
Validation Data ◽  
Method Performance

Abstract During the “Standards Development and International Harmonization: AOAC INTERNATIONAL Mid- Year Meeting,” held on June 29, 2011, an Expert Review Panel (ERP) reviewed the method for the “Determination of Vitamins A (Retinol) and E (alpha-Tocopherol) in Foods by Liquid Chromatography: Collaborative Study,” published by Jonathan W. DeVries and Karlene R. Silvera in J. AOAC Int. in 2002. After evaluation of the original validation data, an ERP agreed in June 2011 that the method meets standard method performance requirements (SMPRs) for vitamin A, as articulated by the Stakeholder Panel on Infant Formula and Adult Nutritionals. The ERP granted the method First Action status, applicable to determining vitamin A in ready-to-eat infant and adult nutritional formula. In an effort to achieve Final Action status, it was recommended that additional information be generated for different types of infant and adult nutritional formula matrixes at varied concentration levels as indicated in the vitamin A (retinol) SMPR. Existing AOAC LC methods are suited for specific vitamin A analytical applications. The original method differs from existing methods in that it can be used to assay samples in all nine sectors of the food matrix. One sector of the food matrix was powdered infant formula and gave support for the First Action approval for vitamin A in infant and adult nutritional formula. In this method, standards and test samples are saponified in basic ethanol–water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters to retinol. Retinol is quantitated by an LC method, using UV detection at 313 or 328 nm for retinol. Vitamin concentration is calculated by comparison of the peak heights or peak areas of retinol in test samples with those of standards.

scholarly journals Liquid chromatographic determination of glyphosate and aminomethylphosphonic acid residues in rapeseed with MS/MS detection or derivatization/fluorescence detection

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Piotr Kaczyński ◽  
Bożena Łozowicka
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Correlation Coefficients ◽  
Chromatographic Determination ◽  
Triple Quadrupole ◽  
Ms Detection ◽  
Aminomethylphosphonic Acid ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

AbstractGlyphosate and AMPA determinations in rapeseed extracts by (a) liquid chromatography with triple quadrupole MS detection (LC-MS/MS), or (b) liquid chromatography with post-column OPA derivatization and fluorescence detection (LC-FLD) were developed. Mean recoveries for glyphosate and AMPA were (a) 88.8–95.0% and 82.1–86.1%, and (b) 70.8–74.1% and 62.4–72.6%. RSD were below (a) 11% and (b) 22%. Correlation coefficients were above 0.997 for both methods. LOD were 0.01 mg kg

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