Construction and application of phenytoin anion-selective electrode based on bulk acoustic wave (BAW) sensing technique

This paper describes the construction of an anion-selective bulk acoustic w ave (BAW) sensor for the direct determination of phenytoin sodium for the f irst time. Based on the sensitive mass response of a piezoelectric quartz c rystal (PQC) and selective adsorption-desorption across the modified film, the BAW sensor was fabricated by coating a polyvinylchloride (PVC) film con taining activator on one side of a PQC. The method was found to be sensitiv e, rapid and easy to handle without pretreatment of the sample. The logarit hm of the frequency shift of the PQC shows a linear relationship to the log arithm of the concentration of phenytoin over the range 6.7 x 10(-8)-8.0 x 10(-4) M with a detection limit of 1.0 x 10(-8) M at pH 10.0. Recoveries we re in the range 98.5-102.0%. Influencing factors were examined and optimize d. Also discussed is the preliminary application of the phenytoin BAW senso r in serum and injection. The results for real samples obtained by the prop osed method agreed with those obtained by conventional methods.