Determination of Amino Acids in Food and Feed by Derivatization with 6-Aminoquinolyl-N-Hydroxysuccinimidyl Carbamate and Reversed-Phase Liquid Chromatographic Separation

1995 ◽  
Vol 78 (3) ◽  
pp. 736-743 ◽  
Author(s):  
Hong Ji Liu ◽  
Bi Ying Chang ◽  
Hui Wen Yan ◽  
Feng Hua Yu ◽  
Xing Xiang Liu
Keyword(s):  
Amino Acids ◽  
Reversed Phase ◽  
Exchange Chromatography ◽  
Cysteic Acid ◽  
Precolumn Derivatization ◽  
Methionine Sulfone ◽  
Relative Standard ◽  
Food And Feed ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A study of a new amino acid analysis method using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as a precolumn derivatization reagent for the analysis of food and feed is described. All amino acids, including methionine sulfone and cysteic acid, were well separated on a liquid chromatographic system using the optimized chromatographic conditions. Salts in food and feed interfered very slightly with the derivatization yields of all amino acids. Several typical agricultural products and animal feeds, including 2 AOAC test samples, were analyzed with the method. The results agreed well with the data generated by using the classical postcolumn method with ion-exchange chromatography. The average relative standard deviations for corn and broiler starter feed were 0.74 and 0.70%, respectively. Good recoveries of all amino acids were demonstrated (average, 101%), even for a sample with a very complex matrix.

Comparison of Liquid Chromatographic Method to AOAC Microbiological Method for Determination of L-Tryptophan in Tablets and Capsules

1993 ◽  
Vol 76 (2) ◽  
pp. 414-417 ◽  
Author(s):  
Henry S Kim ◽  
Gerald Angyal
Keyword(s):  
Reversed Phase ◽  
Precolumn Derivatization ◽  
Microbiological Method ◽  
Test Portion ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Phase Liquid ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A reversed-phase liquid chromatographic (LC) method coupled with precolumn derivatization of L-tryptophan with phenylisothiocyanate was compared to the AOAC microbiological method for determining L-tryptophan in tablets and capsules. For the microbiological method, the concentrations of L-tryptophan were 4-8% lower in autoclaved test samples (hot method) than in test samples that were not autoclaved (cold method). When L-tryptophan values obtained by the LC method were compared to those obtained by the cold microbiological method, no significant differences were observed (P > 0.05). The mean relative standard deviations were 2.9% for the LC method and 1.6% for the cold microbiological method. The mean recoveries of standard L-tryptophan added before analysis were 99% for the LC method and 101 % for the cold microbiological method. These results demonstrate that both methods are reliable for determining free L-tryptophan contained in tablets and capsules. However, the LC method has the advantages of using a smaller test portion and having a shorter analysis time.

Reversed-Phase Liquid Chromatographic Determination of Hypoglycin A (HG-A) in Canned Ackee Fruit Samples

1994 ◽  
Vol 77 (5) ◽  
pp. 1175-1179 ◽  
Author(s):  
Ghulam Sarwar ◽  
Herbert G Botting
Keyword(s):  
Amino Acids ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Precolumn Derivatization ◽  
Edible Portion ◽  
Fruit Samples ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reversed-phase liquid chromatographic (LC) method involving precolumn derivatization with phenylisothiocyanate (PITC) was developed for determining levels of hypoglycin A (HG-A) in canned ackee fruit samples. HG-A was extracted by homogenizing the drained fruit in 80% ethanol. By using a Waters Pico-Tag amino acid analysis 15-cm-long column (which is also used for analyzing protein hydrolysates and biological samples) and an LC system, the baseline separation of HG-A from other amino acids was completed in about 6 min. The total time for analysis and equilibration was 16 min. HG-A levels in the edible portion of fruit in 18 cans varied from 18.27 to 87.50 mg HG-A/can. Recoveries of added standard HG-A averaged 101%. To our knowledge, this is the first report of the use of this method to determine HG-A in ackee fruit.

scholarly journals Application of Liquid Chromatography to the Simultaneous Determination of Acetylsalicylic Acid, Caffeine, Codeine, Paracetamol, Pyridoxine, and Thiamine in Pharmaceutical Preparations

2001 ◽  
Vol 84 (3) ◽  
pp. 676-683 ◽  
Author(s):  
Natividad Ramos-Martos ◽  
Francisco Aguirre-Gómez ◽  
Antonio Molina-Díaz ◽  
Luis F Capitán-Vallvey
Keyword(s):  
Salicylic Acid ◽  
Acetylsalicylic Acid ◽  
Simultaneous Determination ◽  
Pharmaceutical Preparations ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract This paper describes a rapid reversed-phase liquid chromatographic method, with UV detection, for the simultaneous determination of acetylsalicylic acid, caffeine, codeine, paracetamol, pyridoxine, and thiamine in pharmaceutical preparations. A reversed-phase C18 Nucleosil column is used. The mobile phase consists of 2 successive eluants: water (5 min) and acetonitrile–water (75 + 25, v/v; 9 min), both adjusted to pH 2.1 with phosphoric acid. Before determination acetylsalicylic acid is completely converted to salicylic acid by alkaline hydrolysis. Salicylic acid, caffeine, paracetamol, pyridoxine, and thiamine are all detected at 285 nm, whereas codeine is detected at 240 nm. Calibration curves were linear for salicylic acid, caffeine, paracetamol, and pyridoxine in the range of 50–500 mg/L, and for codeine and thiamine in the range of 50–1000 mg/L. The method was applied to the analysis of 13 fortified commercial pharmaceutical preparations. Recoveries ranged from 92.6 to 105.5%, with relative standard deviations of 1.1–5.8%.

Separation of Proteic Primary Amino Acids under Several Reversed‐Phase Liquid Chromatographic Conditions

2006 ◽  
Vol 29 (17) ◽  
pp. 2521-2536 ◽  
Author(s):  
V. Concha‐Herrera ◽  
J. R. Torres‐Lapasió ◽  
G. Vivó‐Truyols ◽  
M. C. García‐Álvarez‐Coque
Keyword(s):  
Amino Acids ◽  
Reversed Phase ◽  
Primary Amino ◽  
Phase Liquid ◽  
Liquid Chromatographic

Quantitative Analysis of Methionine, Cysteine, and Lysine in Feeds by Reversephase Liquid Chromatography Using Precolumn Derivatization with 9- Fluorenylmethyl Chloroformate: Preliminary Study

1990 ◽  
Vol 73 (6) ◽  
pp. 935-939 ◽  
Author(s):  
Angel Cubedo Fernández-Trapiella
Keyword(s):  
Amino Acids ◽  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
Performic Acid ◽  
Cysteic Acid ◽  
Precolumn Derivatization ◽  
Fluorescence Detector ◽  
Reverse Phase ◽  
Reverse Phase Liquid Chromatography ◽  
Phase Liquid

Abstract An Improved analytical method based on precolumn derivatization with 9-fluorenylmethyl chloroformate (9-FMC) and reverse- phase liquid chromatography was developed for quantitative analysis of methionine, cysteine, and lysine In feeds. Samples of corn, whey powder, soybean meal, meat meal, and fish meal were selected for an accurate determination of these 3 amino acids. A portion of each finely ground sample was weighed and subjected to oxidation with performic acid for 16 h before hydrolysis with 6N HCI for 24 h. An aliquot of each hydrolysate was evaporated, dissolved, and diluted with 0.2M pH 7.85 borate buffer. An aliquot of each final solution was derlvatlzed with 9-FMC and analyzed by reverse- phase liquid chromatography using a fluorescence detector with a 254 nm excitation filter and a 313 nm emission filter. The 2 sulfur amino acids and lysine were perfectly separated from all other amino acids with a simple binary gradient. Cysteine (analyzed as cysteic acid), methionine (as methionine sulfone), and lysine were quantltated using internal standard calibration. Hydrolysates were also analyzed by conventional Ion-exchange chromatography (IEC). Amino acid values as obtained by the proposed LC method were close to IEC data. Considering IEC results as reference values, the differences In recovery of amino acids In feedstuffs determined by both methods were not more than 7.5%. Precision of the LC method was evaluated within a single hydrolysate and between different hydrolysates of a single sample. Coefficients of variation (CV) were not more than 4.1 and 5.9%, respectively.

scholarly journals Simultaneous Determination of Bioactive Xanthone Glycosides and Norlignans from Ethanolic Extract of Anemarrhena asphodeloides by Liquid Chromatography

2008 ◽  
Vol 91 (6) ◽  
pp. 1271-1277 ◽  
Author(s):  
M Nurul Islam ◽  
Hye Hyun Yoo ◽  
Jun Lee ◽  
Joo Won Nam ◽  
Eun Kyoung Seo ◽  
...  
Keyword(s):  
Ethanolic Extract ◽  
Reversed Phase ◽  
Linear Behavior ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Aggregation Inhibition ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Anemarrhena Asphodeloides

Abstract The rhizomes of Anemarrhena asphodeloides Bunge (Liliaceae) are prescribed as crude drugs in herbal medication for the treatment of various diseases such as diabetes, inflammation, and platelet aggregation inhibition. A simple, sensitive, and precise reversed-phase liquid chromatographic method was developed to study the quantitative determination of 5 bioactive compounds from these rhizomes, namely, neomangiferin, mangiferin, isomangiferin, nyasol, and methylnyasol. Chromatographic analysis was performed on Capcell Pak C18 column (150 4.6 mm, 3 m) with a mobile phase consisting of acetonitrile, methanol, and 0.1 formic acid at a flow rate of 1.00 mL/min. Quantitation was performed using a UV-visible detector at 260 nm. The method for the determination of reported medicinal agents was accurate and reproducible. Excellent linear behavior was observed over the investigated concentration range of 2.5100.0 g/mL for neomangiferin; 1.560.0 g/mL for mangiferin; 0.520.0 g/mL for nyasol; and 0.220.0 g/mL for methylnyasol; correlation coefficient >0.99. The intraday and interday precision over the concentration range of compounds was <6.6 (relative standard deviation) and accuracy was between 94.9 and 109.3. This method can be successfully applied for the analysis of medicinal compounds from the ethanolic extract of A. asphodeloides Bunge.

Liquid Chromatographic Determination of 2-Chloro-4-nitroaniline, 2-Naphthol, and 2,4-Dinitroaniline in D&C Red No. 36

1993 ◽  
Vol 76 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Alan L Scher ◽  
Nicholas C Adamo
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Calibration Data ◽  
Reversed Phase Liquid Chromatography ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Cellulose Column

Abstract A method is described for the determination of the intermediates and a related impurity in D&C Red No. 36 by reversed-phase liquid chromatography. This method may be used to ensure that limits set forth in the Code of Federal Regulations on the amounts of these 3 impurities in the color are not exceeded. The pigment is dissolved in boiling dioxane and then precipitated. The filtrate is chromatographed by isocratic elution, and then the column is washed and reequilibrated. Impurities were identified as 2-chloro-4-nitroaniline (2-CI-4-NA), 2-naphthol, and 2,4-dinitroaniline (2,4-DNA) by comparison of their retention times and spectra with those of standards. Peak area calibrations were linear to at least 0.375% 2-CI-4-NA, 1.25% 2-naphthol, and 0.025% 2,4-DNA, all with zero intercepts. At the specification levels, 99% confidence limits were 0.30 ± 0.006% for 2-CI-4-NA, 1.0 ± 0.03% for 2-naphthol, and 0.020 ± 0.0004% for 2,4-DNA. The limits of determination calculated from calibration data were 0.019% for 2-CI-4-NA, 0.10% for 2-naphthol, and 0.0014% for 2,4-DNA at the 99% confidence level. Recoveries were 100-104% for 2-CI-4-NA added to purified D&C Red No. 36,100% for 2-naphthol, and 100-110% for 2,4-DNA; relative standard deviations were 0.8-3.4%. A survey of certified D&C Red No. 36 samples showed that the batches contained higher levels of intermediates than were determined previously by a cellulose column method in which the pigment was not dissolved.

scholarly journals Reversed-Phase Liquid Chromatographic Profile of Free Amino Acids in Strawberry-tree (Arbutus unedo L.) Honey

2009 ◽  
Vol 92 (4) ◽  
pp. S1145-S1156 ◽  
Author(s):  
Nadia Spano ◽  
Irene Piras ◽  
Marco Ciulu ◽  
Ignazio Floris ◽  
Angelo Panzanelli ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Reversed Phase ◽  
Arbutus Unedo ◽  
Strawberry Tree ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract The typical profile of the free amino acids contained in strawberry-tree (Arbutus unedo L.) honey is reported for the first time. An optimized reversed-phase liquid chromatographic (RP-LC) method with phenyl isothiocyanate precolumn derivatization was used. Fourteen free amino acids were identified and quantified in 16 analytical samples. Proline (65.63) was found to be the most abundant free amino acid, followed by glutamic acid (6.49), arginine (5.21), alanine (5.17), and phenylalanine (4.97). The total free amino acid content of strawberry-tree honey (average value, 436 mg/kg) was found to be low in comparison to amounts cited in the literature concerning unifloral honeys. The analytical method was optimized and fully validated in terms of detection and quantitation limits, precision (by testing repeatability and reproducibility), linearity, and bias (by means of recovery tests). The acceptability of the validation protocol results was verified using Horwitz's mathematical model and AOAC guidelines.

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