Abstract:
Research on the optimization of modified chitosan membrane based on immobilized enzymes on optical
biosensors has been carried out. The aim of the study was to determine the optimum conditions and characterization of
natural zeolite-modified chitosan membrane in immobilized chitin deasetylase enzyme and determine the
characterization of optical biosensors using modified chitosan membrane to monitor Cd (II) ions in water samples. The
method used in this study is the design of chitosan membrane by dissolving 12 mg of deasetylase into a buffer solution
and then part of the solution is dripped into a circular membrane. The membrane is then dried. all processes were carried
out by comparison of chitosan: natural zeolite: chitin deasetylase (1; 1; 1 ; 1; 1; 2 dan 1; 2;1 dan 1 ; 2;2 ) until the
covalent bond between chitin deasetylase and chitosan is well formed. after immobilization of chitin deasetylase is
complete, the membrane is attached to the pH of the paper which is also in the form of a circle, which is the same as the
membrane and then placed in a flow. Characterization of chitosan membrane and optical biosensor was carried out
including testing of membrane permeability properties, percentage of inhibition and measurement concentration range as
well as detection limit value. The results showed that the optimum conditions of chitosan membrane were obtained in the
ratio of chitosan: natural zeolite concentration: chitin deasetylase of 1: 2: 2, where membrane permeability increased the
concentration of natural zeolite. percentage of inhibition on optical biosensors of 27,126 % dan29,461% with a
measurement concentration range of 1,0 x 10-8 – 1.0 x 10-5 M or equivalent 0,0830 - 8,30 ppm (10-3 Cd (II) 83,0 ppm).
The detection limit value generated is equal to 6,5 and 6,8 or equivalent 5 x 10-6 M (0,028 ppm) and 5,3 x 10-6 M (0,033
ppm). this value is relatively small for the measurement of Cd (II) ions when compared with the AAS measurement
technique with the detection limit value 0,001 –
