Speciation of organomercury compounds by capillary electrophoresis with pre-column derivatization and on-line stacking

Simultaneous separation and detection of three organomercury species, namely methylmercury(MeHg),ethylmercury(EtHg), and phenylmercury(PhHg), was performed by using capillary electrophoresis(CE)with UV detection. Pre-column derivatization with thiosalicylic acid and on-line salt-induced stacking significantly improved the detection performance. Buffer pH, ion strength, and additive were optimized for CE separation, concentration of NaCl in sample solution and injection time were optimized for on-line stacking. The limits of detection were 76.9,83.0 and 76.4 μg/L for PhHg, EtHg and MeHg, respectively. The developed method was validated by certified reference material and liquid chromatography-atomic fluorescence spectroscopy, which suggests this method could be useful in the speciation of organomercury compounds in biological samples.

免疫亲和柱净化-在线柱后光化学衍生HPLC-FLD检测莲子中黄曲霉毒素B_1,B_2,G_1,G_2及其液质确证

目的:建立高效液相色谱-在线柱后光化学衍生-荧光检测器检测药食同源中药材莲子中黄曲霉毒素B1,B2,G1,G2的含量,并采用液质联用法进行确证。方法:样品以甲醇-水(80∶20)溶液提取,经免疫亲和柱净化后,利用在线柱后光化学衍生-HPLC-FLD进行分析测定。并进一步采用LC-MS/MS对阳性样品进行确证。结果:在优化条件下,黄曲霉毒素B1,G1在0.3～30μg.L-1,黄曲霉毒素B2,G2在0.09～9.0μg.L-1线性关系良好,r>0.999 9,回收率86.7%～99.1%,RSD<4.87%。黄曲霉毒素B1,B2,G1,G2的检测限(LOD)分别为0.08,0.03,0.10,0.03μg.kg-1。所测的20批莲子样品中,有14批样品的黄曲霉毒素检测结果呈阳性,其中黄曲霉毒素B1的污染水平为0.40～586μg.kg-1,黄曲霉毒素总量(B1+B2+G1+G2)的污染水平为0.40～602.5μg.kg-1。通过LC-MS/MS确证,在与对照品相同的保留时间处,样品与对照品有相同的特征离子碎片,排除了样品假阳性的可能。结论:该方法简便快速,灵敏度高,重复性好,适用于莲子中黄曲霉毒素的检测。