牙菌斑有机酸的气相色谱-质谱分析

Analysis of Organic Acids in Human Dental Plaque by Means of Gas Chromatography/Mass Spectrometry

采用 Ｇ Ｃ／ Ｍ Ｓ联用技术分析了正常人牙菌斑内有机酸成分。发现了 １４ 种有机酸，其中有 ８ 种直链饱和脂肪酸、４ 种直链非饱和脂肪酸、２ 种芳香酸。含量最多的是 Ｃ１６∶０， Ｃ１８∶０， Ｃ１８∶１３ 种脂肪酸。其中苯乙酸、苯丙酸及十五碳酸等 ３ 种成分是第 １ 次在牙菌斑中检测出。

The purpose of this study was to investigate the composition of plaque fatty acids in the healthy population.The study was made on 10 volunteers over the age of 18 who were divided into three sub\|groups (3\|4 individuals). Neither subject exhibited clinical evidence of salivary gland disorder and any medication affecting salivary functions were not used.A sensitive GC/MS method with VG7070E mass spectrometer was developed in our study. The sample separation was carried out on a fused silica capillary column with OV\|1. The column size was 23 m×0.23 mm. The temperature program was as follows:from 40 ℃ to 120 ℃ fast, then from 120 ℃ to 240 ℃ at 6 ℃/min.The results showed that there were 14 organic acids and isomers present in plaque. They were C 12∶0 ,C 14∶0 ,C 15∶0 ,C 16∶0 ,C 16∶1 ,C 18∶0 ,C 18∶1 ,C 18∶2 ,C 20∶0 and phenylacetic acid, phenylpropionic acid. The higher content of fatty acids in the sample were C 16∶0 ,C 18∶0 ,and C 18∶1 . The aromatic acids were detected only in some samples. The odd\|numbers fatty acids and aromatic acids were for the first time detected.The origin of organic acids in plaque is an ongoing area of research. Our data clearly identify the bacterial contribution to the organic acids of plaque matrix, which may have a special relationship with bacteria metabolism.The research will help us to understand fatty acids metabolism of dental plaque and to determine their role in the microbial homeostasis of dental plaque.