PubMed1997
Concentrations of elements, especially of trace elements toxic as well as non-toxic in biological materials show a high degree of biological, seasonal and spatial variability. These factors should be taken care of while sampling. Samples, even though collected at a great distance of time and space, should be representative and quantitatively comparable which is important for biomonitoring. Reference Materials (RM's) from biological materials such as leaves acquire importance in Analytical Quality Assurance work. A knowledge of element concentrations in highly consumed leafy samples is of interest. A large number of medicinally important leafy samples (50) have been analysed for elemental concentrations such as Zn, Cu, Ni, Co, Pb, As, Se, K, Cr, Na, P, S, Fe, Ca Mg, Mn and Fe. The concentrations of macro nutrients such as Ca, P, Mg, K, Fe and S range from 9.62 to 4174, 1.00-8.630, 3.53-35.50, 12.04-56.28, 0.111-3.845 g/kg and 1.124-5.843 mg/kg, of micro nutrients such as Cr, Co, Cu, Mn, Na and Zn range from 0.360-8.630, 0.050-3.470, 17.60-57.30, 10.5-81.6, 1.47-27.10 and 10.06-145.6 mg/kg whereas those of trace metals such as Pb, Cd, Ni, As and Se range from 1.19-16.30, 0.0036-0.453, 1.23-19.60, 0.12-7.360 and 0.654-3.50 mg/kg respectively. Influence of sampling parameters such as season and spatial variations has been assessed and the results are interpreted. Spatial variation and seasonal variation are observed to be statistically significant for Cu, Zn and Mn. Preparation of Secondary Reference Materials (SRM's) from the samples analysed is explored. Nutritive values of the leaves and intercorrelation between the metals are also discussed.