Capillary electrophoresis with capacitively coupled contactless conductivity detection for the determination of urinary ethylmalonic acid for the diagnosis of ethylmalonic aciduria

Ethylmalonic acid is a metabolic organic acid, and its accumulation in urine is diagnostic of ethylmalonic aciduria. In this study, a simple and fast method employing capillary electrophoresis equipped with capacitively coupled contactless conductivity detection was developed for the detection of ethylmalonic acid in urine samples. The optimized electrophoretic separation was performed in 50 mmol/L 2‐(N‐morpholino)ethanesulfonic acid solution, buffered at a pH of 6.5, and contained 0.13 mmol/L cetyltrimethylammonium bromide as an electroosmotic modifier. Electrophoresis was run at 28 kV in reversed polarity. The linear range of ethylmalonic acid concentration was between 1 and 100 mg/L with a regression coefficient of 0.9998. This method had good intra‐ and interday precision with <5% relative standard deviations. The detection limit (signal‐to‐noise ratio = 3) and the quantification limit (signal‐to‐noise ratio = 10) values were 0.139 and 0.466 mg/L, respectively. Using our optimized conditions, the method was successfully employed for the detection of ethylmalonic acid in urine sample of ethylmalonic aciduria patient.     

固相微萃取-气相色谱-质谱法鉴别海南黄花梨木与越南黄花梨木

采用固相微萃取-气相色谱-质谱法(SPME-GC-MS)研究了海南黄花梨木与越南黄花梨木中的挥发性成分,并对二者进行了鉴别。用电钻在黄花梨木上钻取少量粉末,采用SPME富集挥发性成分,经AB-FFAP极性毛细管气相色谱柱分离,共鉴定出20种挥发性成分,并发现了可用于鉴别海南黄花梨木与越南黄花梨木的两对特征成分:2-(1,1-二甲基乙基)-5-庚基-5-甲基-1,3-二氧戊环-4-酮与2,6,10-三甲基-7,10-环氧-2,11-十二碳二烯-6-醇、2-甲基亚丁基-环戊烷与2-(5-甲基-2-呋喃基)丙醛,并利用其相对含量的关系对海南黄花梨木与越南黄花梨木进行鉴别。该方法具有样品用量小、操作简便快速、不损害整体结构等特点,可用于黄花梨木挥发性成分的分析研究,亦适用于海南黄花梨木与越南黄花梨木的树种鉴别,在家具、工艺品及原木等的鉴别中具有广泛的应用前景。