Risk assessment of diabetes mellitus using dried saliva spot followed by ultra-performance liquid chromatography with fluorescence and mass spectrometry

摘要

The dried saliva spot (DSS) seems to be a convenient sampling technique for bioanalysis. In our previous research, the DSS sampling was used for the determination of DL-lactic acid (DL-LA) and the D/L ratio of diabetic, pre-diabetic and healthy persons. However, the method required an expensive tandem MS/MS apparatus to obtain a highly sensitive detection. To avoid the use of such instrument, this paper proposes cheaper determination systems by ultra-performance liquid chromatography (UPLC) with fluorescence (FLR) and/or single mass spectrometry (MS). The carboxylic acids including DL-LA in the DSS were labeled with a chiral fluorescence reagent, (S)(+)-4-nitro-7-(3-aminopyrrolidin-1-yl)-2,1,3-benzoxadiazole (NBD-(5)(+)-APy), and determined by UPLC-FLR-MS. The limits of detection of LA by FLR and MS were approximately 1.0 mu M (0.1 pmol) and 0.20 mu M (0.02 pmol), respectively, whereas the limits of quantification were 5.0 mu M (0.5 pmol) by FLR and 1.0 mu M (0.1 pmol) by MS. The proposed DSS method was used for the determination of the enantiomers of LA of diabetic, pre-diabetic and healthy persons. The D/L-LA ratios obtained from the FLR were correlated with those of MS, although the ratios of the FLR were slightly lower than those of MS. Furthermore, the D/L-LA ratios of the present FLR or single MS were well correlated with those of the tandem MS/MS obtained from our previous study. The results indicated that the UPLC-FLR-MS was alterable to the previous UPLC-MS/MS method. Consequently, the proposed UPLC-FLR and/or UPLC-MS seem to be applicable as a cheaper screening method for diabetes mellitus using the DSS sampling.