Correia Daniela P A, Magalhães Júlia M C S, Machado Adélio A S C
LAQUIPAI, Chemistry Department, Faculdade de Ciências do Porto, R. Campo Alegre 687, Porto, Portugal.
Talanta. 2005 Oct 15;67(4):773-82. doi: 10.1016/j.talanta.2005.04.003.
Urea biosensors based on urease immobilized by crosslinking with BSA and glutaraldehyde coupled to ammonium ion-selective electrodes were included in arrays together with potassium, sodium and ammonium PVC membrane ion-selective electrodes. Multivariate calibration models based on PCR and PLS2 were built and tested for the simultaneous determination of urea and potassium. The results show that it is possible to obtain PCR and PLS2 calibration models for simultaneous determination of these two species, based on a very small set of calibration samples (nine samples). Coupling of biosensors with ion-selective electrodes in arrays of sensors raises a few problems related to the limited stability of response and unidirectional cross-talk of the biosensors, and this matter was also subjected to investigation in this work. Up to three identical urea biosensors were included in the arrays, and the data analysis procedure allowed the assessment of the relative performance of the sensors. The results show that at least two urea biosensors should be included in the array to improve urea determination. The prediction errors of the concentration of urea and potassium in the blood serum samples analyzed with this array and a PLS2 calibration model, based on nine calibration samples, were lower than 10 and 5%, respectively.
基于脲酶通过与牛血清白蛋白交联并与戊二醛偶联固定在铵离子选择性电极上的尿素生物传感器，与钾、钠和铵聚氯乙烯膜离子选择性电极一起被纳入阵列中。建立了基于主成分回归（PCR）和偏最小二乘判别分析（PLS2）的多变量校准模型，并对尿素和钾的同时测定进行了测试。结果表明，基于非常少量的校准样品（九个样品），有可能获得用于同时测定这两种物质的PCR和PLS2校准模型。生物传感器与传感器阵列中的离子选择性电极耦合会引发一些与生物传感器响应稳定性有限和单向串扰相关的问题，这项工作也对该问题进行了研究。阵列中最多包含三个相同的尿素生物传感器，数据分析程序允许评估传感器的相对性能。结果表明，阵列中应至少包含两个尿素生物传感器以改善尿素测定。使用该阵列和基于九个校准样品的PLS2校准模型分析的血清样品中尿素和钾浓度的预测误差分别低于10%和5%。
