Ricciutelli M, Moretti S, Galarini R, Sagratini G, Mari M, Lucarini S, Vittori S, Caprioli G. Identification and quantification of new isomers of isopropyl-malic acid in wine by
LC-IT and LC-Q-Orbitrap.
Food Chem 2019;
294:390-396. [PMID:
31126479 DOI:
10.1016/j.foodchem.2019.05.068]
[Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 11/18/2022]
Abstract
Organic acids of wine comprise one of the main taste groups, that of sourness. Two isomeric compounds with molecular weight of 176 u have been identified in wine using two LC-MS systems, LC-IT (ion trap) and LC-Q-Orbitrap. The two isomers are organic acids, 3-isopropylmalic acid (3-IPMA) never identified in wines, and 2-isopropylmalic acid (2-IPMA), never quantified in wines. After the definitive identification against the authentic standards, an analytical method for their determination in wines was optimised and validated using the LC-IT platform. Linearity was verified in the range 5-320 mg L-1 (correlation coefficients higher than 0.9914) and the recoveries obtained spiking the samples at two fortification levels were higher than 86.7%, with RSDs (n = 9) lower than 15.1%. Finally, the two compounds were quantified in ten red and white Italian wines, and average concentrations were determined at 1.78 mg L-1 (0.56-4.13) and 23.0 mg L-1 (6.7-41.6) of 3-IPMA and 2-IPMA, respectively.
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