Carbon Paste Electrode Modified Imprinted Zeolite as a Selective Sensor for Creatine Analysis by Potentiometry

Carbon paste electrode modified imprinted zeolite have been developed as a sensor to analyze creatine by potentiometry. Zeolite used in this study was TS-1 type zeolite that was synthesized with mole ratio of TEOS, TBOT, TPAOH, and H ₂ O of 1:0.017:0.24:21.2. Imprinted zeolite (IZ) was synthesized by mole ratio of creatine/Si of 0.0306. The developed electrode showed the optimum performance on pH 5, range of measurement of 10 ^-9 -10 ^-4 M, linearity of 0.973, and Nernst factor of 27.31 mV/decade. The upper and lower detection limits were 5.5×10 ^-5 M and 1.3×10 ^-8 M, respectively. The electrode showed a good precision which is expressed by coefficient of variation of 1.13%-1.43%. The response time of the electrode in 10 ^-9 -10 ^-4 M creatine was 82-199 seconds, while its life time was 7 weeks (83 times used). Urea, glucose, and uric acid in various concentrations did not interfere on creatine analysis by potentiometry using the modified electrode. Application of the modified electrode in two serum samples with spiking technique resulted in recovery of 76.8% and 81.8%. Comparative testing with the standard clinical laboratory method showed accuracy of 73%.