Saurina J, Hernández-Cassou S, Alegret S, Fàbregas E
Department of Chemistry, Autonomous University of Barcelona, Spain.
Biosens Bioelectron. 1999 Jan 1;14(1):67-75. doi: 10.1016/s0956-5663(98)00097-9.
A new potentiometric method is proposed to determine lysine in pharmaceutical samples. This method is based on a lysine biosensor consisting of a chemically immobilized lysine oxidase membrane attached to an all-solid-state ammonium electrode. Lysine is degraded in the sensor to release ammonium, which is detected by means of the ammonium electrode. The presence of endogenous ammonium in the samples interferes with these determinations, since the response measured corresponds to the sum of the ammonium generated enzymatically and that present in the sample. This is a general drawback for all biosensors based on the detection of ammonium. Study of samples containing both lysine and ammonium showed that concentration ranges exist in which a near-logarithmic relationship between potentials measured and lysine concentrations is found. Therefore, within these ranges, lysine can be determined by using the standard addition method, with the subsequent data treatment involving an iterative linearization procedure. Results obtained with the proposed potentiometric method are consistent with those given by the standard method for amino acid analysis.
提出了一种新的电位分析法来测定药物样品中的赖氨酸。该方法基于一种赖氨酸生物传感器，它由附着在全固态铵电极上的化学固定化赖氨酸氧化酶膜组成。赖氨酸在传感器中被降解以释放铵，铵通过铵电极进行检测。样品中内源性铵的存在会干扰这些测定，因为测得的响应对应于酶促产生的铵和样品中存在的铵的总和。这是所有基于铵检测的生物传感器的一个普遍缺点。对含有赖氨酸和铵的样品的研究表明，存在这样的浓度范围，即测得的电位与赖氨酸浓度之间存在近似对数关系。因此，在这些范围内，可以使用标准加入法测定赖氨酸，随后的数据处理涉及迭代线性化程序。所提出的电位分析法得到的结果与氨基酸分析标准方法给出的结果一致。
