Imprinted zeolite modified carbon paste (carbon paste-IZ) electrode had been developed as a sensor to analyze blood glucose content by potentiometry. The used zeolite was Lynde Type A (LTA) that synthesized with a mole ratio of Na2O, Al2O3, SiO2 and H2O of 4:1:1.8:270, respectively while non-imprinted zeolite was prepared with a mole ratio of glucose/Si of 0.0306. Glucose was then extracted from the zeolite framework using hot water (80 °C) to produce imprinted zeolite (IZ). The carbon paste-IZ electrode prepared from activated carbon, paraffin pastilles, and IZ with a mass ratio of 5:4:1 showed the best performance. The modified electrode demonstrated the measurement range of 10–4-10–2 M, the Nernst factor of 29.55 mV/decade, the response time less than 120 s, and the detection limit of 5.62 × 10–5 M. Ascorbic acid, uric acid, urea and creatinine did not interfere on the glucose analysis by potentiometry. Comparison test with spectrophotometry showed an accuracy of (90.7 ± 1.4)% (n = 5), while the application of the electrode to analyze five spiked serum samples showed recovery of (92.2 ± 1.3)% (n = 5). The electrode was stable for up to 9 weeks (168 times usage). Based on its performance, the developed electrode can be applied to analyze glucose in human serum sample and recommended for used in the medical field.

Imprinted zeolite modified carbon paste electrode as a potentiometric sensor for glucose analysis in blood serum sample has been developed. In this study, the type of used zeolite was TS-1. Imprinted zeolite (IZ) was synthesized with mole ratio of glucose/Si of 0.0306. The modified electrode prepared by mixing activated carbon, imprinted zeolite, and paraffin granule with mass ratio 9:4:7 from the measurement in range of 10 -5 -10 -2 M is with Nernst factor of 28.6 mV/decade, and the detection limit of 4.79 x 10 -5 M. The electrode was able to respond the glucose molecules in solution quickly (<30 s), stable for more than 9 weeks (130 times usage) and selective to glucose molecules. The urea, uric acid, and creatine with various concentrations did not interfere to glucose analysis by potentiometry using the electrode. Applying of the electrode for glucose analysis in spiked blood serum samples showed that it had recovery of 91.73±3.48% (n=5), while its accuracy against spectrophotometry method as commonly used method in medical field was 90.58±4.65% (n=5). Based on its performance, potentiometry using the imprinted zeolite modified carbon paste electrode is recommended as an alternative method for routine blood glucose analysis in the medical field.

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A research on the analysis of copper metal in the cooking oil saponification by AAS method. This study aimed to validate analytical methods, including precision and accuracy in the determination of copper metal in cooking oils through saponification and knowing destructed Cu content in cooking oils on the market. This research was done by creating a simulation of cooking oils and then added with a solution with various concentrations of Cu2+, reacted with KOH for saponification, then destructed dried, and absorbance was measured using an atomic absorption spectrometer. Results of accuracy (recovery) be obtained average of 96.88, 97.35, and 97.36% and precision values of 0.8233, 0.3154, and 0.4803%. It can be concluded that this method is very well used to determine the concentration of copper metal contained in cooking oils, and Cu content in cooking oils on the market for bulk cooking oil 1 at 11.5 mg/kg, bulk cooking oil 2 at 10.9 mg/kg, and for branded cooking oil at 7.4 mg/kg.________________________________________GRAPHICAL ABSTRACT

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