Noriyoshi Tamura

Polyvinylhcloride membrane for a glucose sensor

Abstract Glucose oxidase (20 mg/g of carrier) was immobilized on a porous polyvinylchloride membrane (PVC). The stability of the glucose oxidase was improved with immobilization. The glucose oxidase—PVC membrane was applied as a glucose sensor. As assay, reproducible within ± 7% relative error, was completed within 1 min by the steady state method and within 15 s by the kinetic method. Glucose concentrations of fresh sera were determined by the sensor which remained viable for more than 2 months.

Determination of urea in blood serum with use of immobilized urease and a microwave cavity ammonia monitor

Abstract The system for urea determination consists of urease immobilized on porous PVC coated on the inside of a test tube, and a dissolved ammonia monitor comprising a dialyzer and a Stark microwave cavity resonator. The total time required for the determination of urea in serum is 18 min (the enzymatic reaction requires 10 min) and the calibration graph for urea—nitrogen is linear from 10 to 750 mg l00−1. The relative standard deviation is 5%; there are very few interferences.

Preparation and properties of β-glucuronidase immobilized on a polyvinylchloride membrane

Abstract β-Glucuronidase [from bovine liver, EC, 3.2.1.31] was immobilized on various carriers. β-Glucuronidase immobilized on a polyvinylchloride (PVC) membrane showed the highest activity (300 mU/g wet carrier). Then, β-glucoronidase was immobilized on various PVC membranes. The highest activity was observed when β-glucuronidase was immobilized on a swollen PVC membrane. The membrane prepared from the casting solution of 8% PVC was suitable for the immobilization of β-glucuronidase. The activity yield of β-glucuronidase—PVC membrane was from 30 to 50%. No significant difference in pH and temperature stabilities was observed between immobilized β-glucuronidase and native β-glucuronidase. The β-glucuronidase—PVC membrane retained its original activity for two months at 5 °C.