2.5. HNO3 decomposition in open system with cold finger (Procedure 1)
Different parameters may affect the efficiency of decomposition of
samples with a high content of organic compounds: acid volume,
amount of sample used, time, and temperature of decomposition
using the digester block. This efficiency in the decomposition is an important
factor to let the analytes free in the solution, without interfering
or losing analyte and reagent by volatilization. Thus, HNO3 decomposition
in open system with cold finger has been explored for the determination
of volatile elements (Cd, Pb, As and Se) in WR samples using
surface response methodology (SRM). A central composite design