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  • Use of ammonium sulfite as a post-column derivatization reagent for rapid detection and quantification of aldehydes by LC-MS.

Use of ammonium sulfite as a post-column derivatization reagent for rapid detection and quantification of aldehydes by LC-MS.

Talanta (2019-09-14)
Yu-Ning Hu, Di Chen, Tian-Yi Zhang, Jun Ding, Yu-Qi Feng
ABSTRACT

Derivatization is frequently used in liquid chromatography-mass spectrometry (LC-MS) to improve the ionization characteristics of analytes, and facilitate their structural elucidation and quantification. However, the off-line derivatization process usually requires more analysis time. Therefore, the present work develops a novel LC/post-column derivatization (PCD)/MS (LC-PCD-MS) method for rapid detection of aldehydes in complex samples. The PCD method is based on a bisulfite addition reaction with aldehydes that can be easily conducted by mixing the LC elute with an (NH4)2SO3 solution via a tee. The resulting derivatives readily produce diagnostic HSO3- ions under collision induced dissociation (CID) in the negative ion mode of MS, even at an extremely low CID energy such as 1 eV, which can significantly improve the detection selectivity of aldehydes and reduce the occurrence of false positives. The limits of detection (LODs) of hexanal and heptanal were 3 nM and 2 nM, respectively. Moreover, good linearity in the concentration range of 0.01-1 μM for hexanal and heptanal was obtained with the determination coefficient (R2) being greater than 0.996 and the intra- and inter-day relative standard deviations (RSDs) were lower than 13.5% and 17.9%, respectively, indicating the acceptable reproducibility of the method. The LC-PCD-MS method was successfully applied for the rapid quantification of aldehydes in human urine and solvent extracts of traditional Chinese medicines (TCMs). Furthermore, a precursor ion scan strategy based on the diagnostic HSO3- ion was also developed and applied for the preliminary screening of aldehydes in complex samples of cinnamon and lemongrass.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
trans-2-Hexen-1-al, 98%
Sigma-Aldrich
Ammonium sulfite solution, technical, 34%
Sigma-Aldrich
Hexanal, ≥97%, FCC, FG
Sigma-Aldrich
trans-2-Heptenal, ≥95%, stabilized, FG