Aqueous standards were prepared from Custom- Grade Multi-element Solution Var Cal 2 (Inorganic Ventures, Inc.) and from 1,000 mg/L and 10,000 mg/L single element standards (Spectrosol, BDH Chemicals). The standards were made up in 18MW Milli-Q water with 1% v/v high purity HNO3 (Mallinckrodt, AR SELECT PLUS) and 0.01% v/v Triton X100 prepared from a 1% w/v Triton X100 solution. Scandium was added to each solution as an internal standard with a final concentration of 0.5 mg/L.
The following calibration standards were prepared.
Rinse and calibration blank solutions were prepared from 18MW Milli-Q water with 1% HNO3 and 0.01% Triton X100.
Solutions were prepared from Seronorm Trace Elements Serum, batch no. 311089.
The serum was reconstituted by removing the screw cap and carefully lifting the rubber stopper without removing it completely. Air was allowed to enter the vial through the grooves on the lower part of the stopper. The stopper was removed and 3.00 mL of 18MW Milli-Q water was added. Care must be taken when removing the stopper to avoid loss of dried material. The vial was closed and allowed to stand for 30 minutes. The contents were completely dissolved by swirling gently. Shaking of the vial will result in the formation of foam. Long term contact between the liquid and the rubber stopper should be avoided, particularly for the determination of zinc or aluminium, to prevent contamination from the rubber stopper.
Three solutions with dilution factors of 5, 20 and 100 were prepared in 1% HNO3 and 0.01% Triton X100.
Scandium was added to each solution as an internal standard with a final concentration of 0.5 mg/L.