非抑制离子色谱法测定水产品中氧化三甲胺及其分解产物的方法

建立了一种能够同时测定水产品中氧化三甲胺及其分解产物二甲胺和三甲胺的非抑制性离子色谱方法.样品使用10％三氯乙酸溶液浸提,浸提液通过离心,稀释过滤后直接进样；方法使用4mmol/L硝酸+3％乙腈作为淋洗液,色谱分离柱为Metrosep C4 150(150mm×4mm)；二甲胺、氧化三甲胺和三甲胺的保留时间分别为6.22、8.21、9.09min,检出限分别为0.025、0.050、0.050mg/kg;该方法具有较好的线性相关性(r＞0.999),RSD为1.41％～3.83％(n=5),加标回收率为91.5％～100.3％.通过比较,含有内源性甲醛的水产品样品中检出二甲胺,而不含有内源性甲醛的样品没有检测到二甲胺.

Determination of trimethylamine N oxide and its decomposition in fishery products by non suppressed ion chromatography

An ion chromatography method with non suppressed conductivity detection was developed for the simultaneous determination of trimethylamine N oxide (TMAO) and its decomposition products (trimethylamine, TMA, and dimethylamine, DMA) in fishery products. Fishery samples were treated with 10% trichloroacetic acid, afterwards the extracted solution was centrifuged and diluted before injection to the ion chromatography device. The targeted compounds were eluted from a Metrosep C4 150 (150mm×4mm) column by 4mmol/L nitric acid with 3% acetonitrile (v/v). The retention time of DMA, TMAO and TMA were 6.22min, 8.21min and 9.09min, and the detection limits were 0.025mg/kg, 0.050mg/kg and 0.050mg/kg, respectively. The coefficients of linear equations were all above 0.999. The RSD were between 1.41% and 3.83% (n=5), and the recoveries were between 91.5%~100.3%. DMA was found in the samples which contain endogenous formaldehyde, while sample without endogenous formaldehyde was DMA free.