Simultaneous Determination of Mineral Nutrients and Toxic Metals in M. stenopetala from Southern Ethiopia: A Comparative Study of Three Cultivating Areas Using MP-AES

Table 3

Optimization of digestion temperature for 0.5 g of leaf and seed samples at a constant acid mixture volume and digestion time.

Volume ratio (HNO3 : HClO4 : H2O2)	Total volume (mL)	Temp. (°C)	Digestion time (hrs)	Observations
2.5 : 0.75 : 0.5	3.75	60	2:30	Light yellow
2.5 : 0.75 : 0.5	3.75	120	2:30	Colorless and turbid
2.5 : 0.75 : 0.5	3.75	180	2:30	Colorless with suspension
2.5 : 0.75 : 0.5	3.75	240	2:30	Clear and colorless
2.5 : 0.75 : 0.5	3.75	280	2:30	Clear and colorless

The optimal digestion temperature.