Direct competitive enzyme-linked immunosorbent assay for the determination of the highly polar short-chain sulfophenyl carboxylates
Direct competitive enzyme-linked immunosorbent assay for the determination of the highly polar short-chain sulfophenyl carboxylates
复制标题
DOI：
10.1021/ac0502910
复制
发表时间：
2005-08-15
影响因子：
7.4
通讯作者：
Marco, MP
中科院分区：
文献类型：
--
作者：
Estévez, MC;Galve, R;Marco, MP
据报道，一种用于检测直链烷基苯磺酸盐的主要代谢物短链磺基苯基羧酸（SPC）的直接酶联免疫吸附测定法。六个 SPC（2C(3)、2C(4)、X-4、2C(5)、3C(5)、3C(6)），烷基长度不同。已合成了链（C-3 和 C-6 之间）以及苯磺酸基与羧基的位置。已经针对通过将羧酸与赖氨酸氨基酸残基偶联而制备的相应鲎血蓝蛋白缀合物的混合物产生了抗体。使用六种 SPC 的等摩尔混合物作为标准分析物，免疫测定 As115/3C(4)-HRP 的 IC50 值为 23 nM (6.67 mu g L-1)，检测限为 0.85 nM (0.24 mu g L-1)。已发现免疫测定在低或中等离子强度 (4-30 mS cm(-1)) 的介质中效果更好。通过将测定介质的 pH 值降低到 SPC 羧基的 pKa 值以下并使用具有螯合特性的缓冲液（例如柠檬酸盐缓冲液），可以防止因与二价阳离子（例如 Ca2+）形成 SPC 盐而导致的可检测性降低。该测定可被认为是针对短链 SPC 的特异性分析，因为具有较长烷基链的同源物和结构中含有磺酸基的其他污染物不会显着干扰该测定。旨在评估该测定在环境水样中的潜在应用的初步实验证明了该测定的有用性。
A direct enzyme-linked immunosorbent assay for the detection of the short-chain sulfophenylcarboxylic acids (SPCs), the main metabolites of the linear alkylbenzenesulfonates, is reported. Six SPCs (2C(3), 2C(4), X-4, 2C(5), 3C(5), 3C(6)), differing in the length of the alkyl. chain (between C-3 and C-6) and in the position of the phenylsulfonic group versus the carboxylic group, have been synthesized. Antibodies have been raised against a mixture of the corresponding horseshoe crab hemocyanin conjugates prepared by coupling the carboxylic acid to the lysine amino acid residues. The immunoassay As115/3C(4)-HRP achieves an IC50 value of 23 nM (6.67 mu g L-1) and a detection limit of 0.85 nM (0.24 mu g L-1), using as standard analyte an equimolar mixture of the six SPCs. The immunoassay has found to work better in media with low or moderate ionic strength (4-30 mS cm(-1)). The decrease in the detectability produced by the potential formation of SPC salts with divalent cations such as Ca2+ can be prevented by lowering the pH of the assay medium below the pKa value of the SPC carboxylic group and using a buffer chelating with properties such as citrate buffer. The assay can be considered specific for short-chain SPCs since congeners with longer alkyl chains and other pollutants containing sulfonic groups in their structure do not interfere significantly in the assay. Preliminary experiments addressed to evaluate the potential application of this assay to environmental water samples demonstrate the usefulness of the assay.