Experiments to determine the sample loading volume
were performed by passing increasing volumes between
250-2000mL at increments of 250mL until 1500mL and at
increments of 50 mL up to 2000 mL) of aqueous solutions
at pH 7 containing 50 g of all ions, through the solid phase
column filled with 1.0 g of alumina, 50 mg of SDS (hemimicellar/
admicellar region), and 20mg BMPBDA, then determining
the amount of all analyte ions eluted with nitric
acid. This trait gives the feasibility of determination of the
sample with different analytes concentration levels. However,
it should be pointed out that the larger amount of the
sample solution, the more time (for passing it through solid
phase) was required in the procedure. To trade off the enrichment
factor and analytical speed, 1800 mL sample and
6.0 mLHNO3 were used; therefore, an enrichment factor of
300 was obtained.