Assessment of Vegetables Using Wavelength Dispersive X-ray Fluorescence (WDXRF) Spectrometer

The objectives of the research were to determine the heavy metals in the vegetable samples in industrial wastewater irrigated areas. Results of vegetables from Dar es Salaam were obtained using Wavelength Dispersive X-Ray Fluorescence (WDXRF). The sample analyzer machine is equipped with Rh anode tube with spot focus operating under vacuum conditions. The operating voltages vary from 20 kV to 60 kV with a current from 50 mA to 5 mA. The characteristic x-rays from the sample were collimated before arriving at the analyzing crystal under a vacuum of 0.05mB and detected using a proportional counter and NaI (Tl) x-ray detector biased at -1000V. The net peak areas of the characteristic lines were determined using a non-linear least square fitting procedure. The whole detection and crystal system was shielded by a 10 mm lead shield. Analysis time ranged between 20-50 seconds for each element and about 100s for the standard sample. Elements in the material range from C, N, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Ni, Mn, Fe, Cu, Zn, Br, Rb, and Sr. The values obtained are within range of those published as essential as foodstuff.