Determination of selected amino acids in milk using dispersive liquid-liquid microextraction and GC-MS

Quigley, Andrew and Connolly, Damian and Cummins, Wayne (2019) Determination of selected amino acids in milk using dispersive liquid-liquid microextraction and GC-MS. Analytical Methods, 11 (28). pp. 3538-3545. ISSN 1759-9660

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Abstract

An ethyl chloroformate derivatisation followed by dispersive liquid-liquid microextraction (DLLME) method combined with GC-MS was developed for the analysis of free amino acids in various milk products. The method was applied to milk samples to investigate any changes in the free amino acid concentration during the shelf life of the product. Both the derivatisation and DLLME procedures were optimised using a design of experiments approach. The optimum derivatisation conditions were determined: 600 μL of both ethyl chloroformate and pyridine for a sample volume of 1 mL. The optimum DLLME conditions were 100 μL of chloroform, 0.89 mL of ACN, and 5 mL of H2O. Under these optimal conditions the method provided linearity in the range of 0.5-9.12 μg mL-1, with R2 values of >0.98. Interday reproducibility ranged from 7.8-10.30% RSD. The LOD ranged from 0.31-0.84 μg mL-1 while the LOQ ranged from 0.95-2.56 μg mL-1. The amino acid concentration was shown to increase significantly for 3 amino acids during the storage period: alanine, glycine, and glutamic acid.

Item Type: Article
Additional Information: Funding Information: The authors wish to thank the Irish Research Council for nancial support of this study [grant number: GOIPG/2015/ 3681]. Publisher Copyright: This journal is © The Royal Society of Chemistry.
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/1600/1602
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Depositing User: Admin SSL
Date Deposited: 19 Oct 2022 23:05
Last Modified: 07 Jun 2023 18:43
URI: http://repository-testing.wit.ie/id/eprint/3983

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