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Chemical derivatization-based liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) technique is an effective analytical tool for trace small-molecular weight compounds analysis present in complex samples. Chemical derivatization technique can improve the detection sensitivity, selectivity, chromatographic separation and identification capability of LC-ESI-MS analysis. In this review, we summarized the progress of chemical derivatization-assisted LC-MS methods in the period of 2014–2018, according to the functional groups of analytes, such as carboxyls, amines, carbonyls, thiols, hydroxyls, phosphates, modified nucleic acids, conjugated dienes and carbon-carbon double bonds. We mainly focused on the reaction principles of representative derivatization reagents with some application cases highlighting the impact of chemical derivatization-assisted LC-MS technique, which would be helpful for the designing and synthesis of new derivatization reagents for the analysis of small-molecular weight compounds in complex samples. • We provide a comprehensive review of derivatization-based LC-MS in the period from 2014 to 2018. • We summarize the principles and properties of representative derivatization reagents. • We discuss the typical application cases of derivatization to highlight their impact. • We describe the advantages and prospects of derivatization based LC-MS. [ABSTRACT FROM AUTHOR]

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 (NH 4) 2 SO 3 solution via a tee. The resulting derivatives readily produce diagnostic HSO 3 − 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 HSO 3 − ion was also developed and applied for the preliminary screening of aldehydes in complex samples of cinnamon and lemongrass. Image 1 • The PCD can be realized by mixing the LC elute and (NH 4) 2 SO 3 solution. • The PCD process enables the on-line derivatization and rapid detection of aldehydes by LC-MS. • Both PCD and ionization efficiency are almost unaffected by interferences. • The diagnostic HSO 3 − ion enabled preliminary screening of aldehydes in complex samples. [ABSTRACT FROM AUTHOR]

A fully automated in-tube solid phase microextraction/liquid chromatography-post column derivatization-mass spectrometry (in-tube SPME/LC-PCD-MS) method was developed for the analysis of urinary hexanal and heptanal. Online in-tube SPME enabled effective enrichment of the low level aldehydes and elimination of matrix interferences. PCD could be simply realized by mixing the LC elute and hydroxylamine hydrochloride (HAHC) solution with just a tee. The peak broadening and loss in separation efficiency associated with post column dead-volume could be ignored and even completely eliminated by employing suitable PCD configuration. What’s more, HAHC is commercially available and quite cheap, and shows no contaminations to MS. The entire procedure, including the extraction of aldehydes by in-tube SPME, LC separation, post column derivatization and MS detection were integrated together and completely automated, offering competitive advantages in terms of rapidity, economy, reproducibility and simplicity. The developed protocol was then successfully performed to determine lung cancer biomarkers (hexanal, heptanal) levels in urine samples. [ABSTRACT FROM AUTHOR]