Abstract
This research work is based on the study of different redox species of iron present in Brassica oleracea var. capitata by using recommended analytical methods reported for UV-Visible spectrophotometer with few modifications. Two methods viz 1,10-Orthophenonthrolein (opt) and potassium thiocyanate (KSCN) methods were applied to determine total and ferric iron form, respectively, and the ferrous was calculated from difference of these two forms. For opt method hydroxylamine hydro chloride was used to reduce all ferric into ferrous. Buffer solution of sodium acetate was used to maintain pH between 5 and 9 and opt was the complexing agent to give orange red Fe (II)-opt complex. Amount of all reagents were set with respect to time for complexation. KSCN method, potassium thiocyanate was used as complexing agent and it gives blood red Fe (III)-SCN complex, so its amount was set with respect to time. Calibration curves drawn for both the Fe (II)-opt and Fe (III)-SCN methods in which correlation coefficients (r2 ) showing good precision of the method was applied for sample analysis. Samples of Brassica oleracea were collected from Malir and Thatta fields irrigated with sewage and fresh water, respectively. Fresh and sewage water samples showed that total iron, ferric and ferrous was 17.0-49.5mg/100g, 9.5-27.4mg/100g, 7.5-14.3mg/100g, 5.18- 12.8mg/100g, 1.00-3.24mg/100g, 2.89-9.4mg/100g, respectively. The results revealed that total iron is found to be high in fresh water samples whereas ferrous is found to be high in the samples irrigated in sewage water collected from Malir fields.
