关键词: 超高效液相色谱-三重四极杆质谱, 母离子扫描, 酰基肉碱, 质谱特征

Abstract:

A parent ion scan driven untargeted method was developed for the determination of acylcarnitines in the urine samples by ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-QqQ MS). The acylcarnitines were extracted with methanol and 1% (v/v) formic acid aqueous solution. After pretreatment, the samples were analyzed without derivatization. The data were acquired by scanning parent ions of three common fragment ions of acylcarnitines, which were m/z 60, 85 and 144. The three obtained chromatograms and their corresponding mass spectra were compared with the recognized acylcarnitine signals. Each parent ion that presented in all the three mass spectra was selected. The chromatograms of these ions were extracted. The generated peaks that had the same retention times in the three chromatograms were considered as candidate acylcarnitines. The structures of these candidates were identified by high resolution MS and MS/MS combined with searching against databases. Authentic standards were employed to confirm the results if they were available. A total of 37 acylcarnitines were identified in the urine samples by the method, including nine short-, 26 medium- and two long-chain acylcarnitines. A number of 14 acylcarnitines of them were unknown compounds which had not been included in the databases. This method could be extended to detect other biological samples, such as blood and tissues, for qualitative or quantitative analysis of acylcarnitines.

Key words: acylcarnitines, mass spectral characteristics, parent ion scan, ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-QqQ MS)