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The determination of polyamines and their N-acetylated forms was performed by ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The polyamines efficiently reacted with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) in 0.1 M borax (pH 9.3) at 60 °C for 30 min. The resulting derivatives were analyzed by electrospray ionization (ESI)-MS and sensitively detected by selected reaction monitoring (SRM). Furthermore, a rapid separation of the polyamine derivatives within 10 min was performed by UPLC using an antipressurized column packed with 1.7-μm octadecylsilyl (ODS) silica gel. The limits of detection (S/N = 3) on the SRM chromatograms were at the attomole level (9-43 amol). This procedure was used to successfully determine 11 polyamines, including their N-acetylated forms, in the saliva of patients with primary and relapsed breast cancer and healthy volunteers. The level of several polyamines (Ac-PUT, Ac-SPD, Ac-SPM, DAc-SPD, and DAc-SPM) increases in breast cancer patients. Furthermore, the levels of three polyamines (Ac-SPM, DAc-SPD, and DAc-SPM) were significantly higher only in the relapsed patients. The present method proved highly sensitive and is characterized by specificity and feasibility for sample analysis. Consequently, the proposed method is useful for the noninvasive salivary diagnosis of cancer patients and could be applied to determine polyamines in several specimens of biological nature.

A simultaneous determination method for the enantiomers of chiral carboxylic acids by the combination of ultraperformance liquid chromatography and mass spectrometry (UPLC-MS/MS) has been developed. (S)(+)-1-(2-Pyrrolidinylmethyl)-pyrrolidine (S-PMP) was used as the derivatization reagent for the high-throughput determination of biological chiral carboxylic acids, i.e., lactic acid (LA) and 3-hydroxybutyric acid (HA). The S-PMP efficiently reacted with the carboxylic acids under mild conditions at room temperature in the presence of 2,2'-dipyridyl disulfide and triphenylphosphine. The resulting S-PMP derivatives were highly responsive in the electrospray ionization (ESI)-MS operating in the positive-ion mode and gave characteristic product ions during the MS/MS, which enabled the sensitive detection using selected reaction monitoring. The derivatization was effective for the enantiomeric separation of the chiral carboxylic acids, and the resolution values of DL-LA and DL-HA were 4.91 and 9.37, respectively. Furthermore, a rapid separation of the derivatives of DL-LA and DL-HA within 7 min was performed using the UPLC system. The limits of detection on the column were in the low femtogram range (5-12 fg). The proposed procedure was successfully applied for the determination of the D- and L-isomers of LA and HA in the saliva of diabetes mellitus (DM) patients and healthy volunteers. The D-LA in DM patients was clearly higher than that in normal subjects. The derivatization followed by UPLC-ESI-MS/MS enabled the enantiomeric separation and detection of trace amounts of LA and HA in human saliva with a simple pretreatment and small sample volume.

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