Simultaneous GC-MS quantitation of phosphoric, aliphatic and aromatic carboxylic acids, proline and hydroxymethylfurfurol as their trimethylsilyl derivatives: In model solutions II

Abstract

Fragmentation patterns and quantitation possibilities of gas chromatography-mass spectrometry (GC-MS) with Ion Trap Detection (ITD) are reported for the trimethylsilyl (TMS) derivatives of selected aliphatic and aromatic/cyclohexanoic, mono-, di- and polyhydroxy/methoxy carboxylic acids,o-phosphoric acid, proline and 5-hydroxymethylfurfurol (HMF)— (common in natural matrices, such as fruits, honey etc.). In order to maintain stability of derivatives, their stock solutions were diluted with hexamethyldisilazane. Quantitation was carried out simultaneously on the basis both of the total ion current (TIC) and selective fragment ion (SFI) values. Data obtained proved that (i) the fragmentation of different TMS acids provided very informative, utilizable characteristics, that were also suitable for quantitation; (ii) the type of fragments do not differ in their m/z values compared to those obtained in the Mass Spectral Database; (iii) the advantages of ITD due to its ‘soft’ fragmentation feature resulted in higher abundance of characteristic ions\([M]^{_ \cdot ^ + }\), ([M−CH3]+, [M+1]+, [M+TMS]+, [M+2TMS]+) compared to the non characteristic reagent ones (at m/z=73,147). Determination of oxalic, glycolic, pyruvic, levulinic, succinic, malic, pimelic, tartaric, citric, palmitic, oleic, stearic, arachidic, shikimic, quinic, chlorogenic acids, as well as those ofo-phosphoric acid, HMF and proline have been carried out in the concentration range of 1–20 ng of compounds. Reproducibility on the basis of TIC and SFI values, in the order listed, proved to be 0.8–8.6% and 1.3–16.0% (relative standard deviation percentages).