Mudasir

In vitro hemocompatibility of PVA-alginate ester as a candidate for hemodialysis membrane.

Alginate based biopolymer with improved physical and chemical properties after esterification using polyvinyl alcohol (PVA) has been studied for possible application as a hemodialysis membrane. The alginic acid to vinyl alcohol molar ratio was predetermined at 0, 0.1, 0.5 and 1. Mechanical strength, hydrophilicity and Ca(2+) adsorption of the membrane before and after modification were evaluated. The obtained PVA-alginate (PVA-Alg) ester membrane was also confirmed using FTIR and SEM. It shows that the PVA-Alg membrane tensile strength is higher than that of native alginate. The water contact angle of the membrane was found to be around 33-50°. The Ca(2+) adsorption capacity tends to decrease with the increase in molar ratio. Furthermore, the modified PVA-Alg ester membrane achieves better protein adsorption and platelet adhesion than the unmodified one. It also exhibits a dialysis performance of 47.1-50.0% for clearance of urea and 42.2-44.6% for clearance of creatinine, respectively. It is expected that this PVA-Alg ester may challenge cellulose acetate for potential application as hemodialysis membranes.

Synthesis 3,4-Dimethoxybenzyl-2,4-Dihydroxyphenyl Ketone from Eugenol

The synthesis of 3,4-dimethoxybenzyl-2.4-dihydroxyphenyl ketone from eugenol have been done by several steps. The first step, methyiation of eugenol to methyleugenol. Then, oxydation of methyleugenol with KMn04 to 3,4-dimethoxy-phenyl acetic acid. The acylation of 3,4-dimethoxy-phenyl acetic acid with resorcinol in BF3 etherate as a catalyst and solvent to furnish compound 3,4-dimethoxybenzyl-2.4-dihvdroxvphenvl ketpne. As further, the ketone compound was usea as precursor for isoflavone synthesis

THE INFLUENCE OF PVA.cl.CITRIC ACID/CHITOSAN MEMBRANE HYDROPHICILITY ON THE TRANSPORT OF CREATININE AND UREA

The influence of cross-linking and membrane hydrophilicity on the transport rate had been studied using a membrane prepared from a mixture of chitosan/PVA cross-linked citric acid (PVA.cl.CA) for creatinine and urea transport. The optimum mole ratio of PVA:citric acid as well as the best composition of chitosan:PVA.cl.CA were determined using creatinine transport study. Using the optimum compositions, further study was done using different thickness of the membrane in transporting creatinine, urea and a mixture of 3 species (creatinine, urea and vitamin B12). Membrane characterization was done using FT-IR spectrophotometer, water absorption test, TG/DTG and SEM. The results showed that the optimum composition PVA:citric acid was obtained to be 90:1, having % WU of 113.74% and creatinine transport percentage of 18.16%. Meanwhile, the optimum composition of chitosan:PVA.cl.CA was found at 4:6 ratio having % WU and % transport of 136.67% and 24.26%, respectively. The optimum transport capacity was found for membrane thickness of 50 μm with WU% at 139.61% and the percent transport of creatinine and urea each was 38.93% and 60.36%. The presence vitamin B12 in the solution of is proved to disturb the transport of creatinine and urea through the membrane. Finally, hydrophilicity seemed to give substantial contribution in the transport process as well as the mechanical strength of the membrane.

EXTRACTION AND SPECIATION OF CHROMIUM(VI) AND CHROMIUM(III) AS ION-ASSOCIATION COMPLEXES OF TETRAMETHYLAMMONIUM-CHROMATE

A specific, selective and simple method for speciation of chromium(VI) and chromium(III) has been developed. This method is based on the quantitative extraction of chromium(VI) and chromium(III) as an ion association of tetramethylammonium-chromate in methyl isobutyl ketone (MIBK), followed by back extraction and preconcentration with an acidic diphenylcarbazide (DPC) solution. Back extraction was applied to achieve further preconcentration by a final factor of 20. The chromium(VI)-DPC complex was determined by a UV-Visible spectrophotometer. The optimum conditions of this method are as follows, optimum wavelength at 545 nm, MIBK as organic solvent, 7.5 mL of nitric acid (65%) for each 100 mL sample, mole ratio of TMAC to Cr(VI) of 2x104:1, 5 min shaking time, mole ratio of DPC to chromium(VI) of 8:1, and immediate UV-Vis measurement after obtaining of backextract. The calibration curve was linear in the concentration range 0.00-0.40 g.mL of chromium(VI) with a regression equation of Abs=0.0038+1.7427x, in which x was the chromium species concentration (g.mL). The correlation coefficient (r) for the curve was 0.9991 and the detection limit was found to be 0.946 ng.mL -1 . The result of analysis and speciation of chromium in water samples from a river near a leather processing plant in Yogyakarta area showed that the total content of chromium was in the range of 0.04 0.05 g.mL consisting of 0.03 0.04 g.mL of chromium(VI) and 0.002 0.01 g.mL of chromium(III). This result indicates that the concentration of chromium in the river is still below the safety limit.