PENGEMBANGAN BEADS PVA-NATRIUM ALGINAT SEBAGAI MATRIKS IMOBILISASI 1,5-DIFENILKARBAZIDA UNTUK DETEKSI Cr(VI); DEVELOPMENT OF PVA-SODIUM ALGINATE BEADS AS IMMOBILIZATION MATRICES OF 1,5–DIPHENYLCARBAZIDE FOR THE DETECTION OF Cr(VI)

Habibah, Nur, Dwi Siswanta

2016 | Disertasi | FMIPA

PVA–sodium alginate beads have been synthesized as a matrix for the immobilization of 1,5–diphenylcarbazide (DPC) as a sensor for the detection of Cr(VI). The aims of this research were to develop Cr(VI) sensor based on solid matrix beads, to study the optimum condition of sensing, to determine the interference of any ions and applying beads sensors for the detection of Cr(VI) in waste water samples. In the presence of Cr(VI), the color of beads sensor changed from pale pink into purple as a result of reaction between Cr(VI) with DPC. Beads were prepared by using PVA–boric acid method. The total concentration of PVA, sodium alginate and DPC is 10% (w/w), 1% (w/w), and 4.53 mg DPC g–1 beads. The resulted beads were characterized by using FTIR spectrometer. The interaction between PVA, sodium alginate, DPC and Cr(VI)–DPC complex proved by the FTIR spectra. The absorbance measurement was carried out at a wavelength of 546.67 nm. The optimum response of the beads sensor was obtained at pH 2, for 8 minutes sensing. The linearity of the calibration curve was obtained in the concentration range of 2–8 mg L–1, with a coefficient correlation of 0.999, limit of detection and limit of quantification for 25 mL sample are 0.11 and 0.34 mg L–1, respectively. The beads sensor has a good precision and accuracy with the relative standard deviation was less than 5% and the % recovery value between 84-119%. The beads sensor exhibited good stability for 30 days. The existence of Hg (II) with the concentration ? 20 mg L–1 could increase the absorbance up to 5.44%, but does not interfere the visual detection process. The beads sensor were applied for determination of Cr(VI) in waste water samples and was able to detect the presence of Cr(VI). The satisfactory results were obtained by measuring the absorbance of beads after sensing in a waste water sample with the accuracy value between 80-96% relative to the reference method.

Kata Kunci : PVA–sodium alginate beads, beads sensors, Cr(VI) detection, DPC