Devoting turbidity measurements via absorptiometry: glutathione determination

The study included estimation of glutathione (GSH) as an important biomarker using turbidimetric method based on reaction of GSH with Ce(IV) in acidic medium to form turbid solution. More than twenty metal ions were used to test their interaction with GSH in acidic medium, it was obtained that only Ce(IV) forms turbid product. Instead of using turbidimeter to conduct measurements, a single beam spectrophotometer was used for this purpose. The measurements were studied at three wavelengths via 500, 700 and 900nm, but a near infrared wavelength, i.e. 900nm, shows the best results. In addition, the effect of temperature, time, type of acid, sequence addition as an optimum conditions required for the product to form were studied. Then the effect of the interferences was studied at two concentrations. A calibration curve in µg.mL-1 was constructed and its trending lies on points of concentrations ranged from 20 to 180µg.mL-1 with a correlation coefficient of 0.9994, and detection limit of 0.0005 µg.mL-1 and slope is (0.0014). The analytical method was applied on samples of human blood serum. The obtained results were compared with the results of the referenced (kit) method. The results obtained by the method followed, some of them were close and the others were far.