Micronutrition in the kernel
After oven-drying to a constant weight, the kernel was triturated. The
triturations from peanuts grown in each district were mixed and used as
one repetition. After adding 6 ml of 15 M nitric acid, the trituration
was stored overnight. Then, 2 ml of 30%
H2O2 was added and the mixture was
digested using a microwave oven high-pressure digestion system (Mars 6
Classic; CEM Corp., USA). The micronutrient contents in the kernel were
determined by ICP–OES.