High-Accuracy Determination of Potassium and Selenium in Human Serum by Two-Step Isotope Dilution ICPMS

Table 1

Instrument parameters.

Parameter	K	Se
ICP RF power (W)	1100	1100
Gas flows (L/min)	0.97	0.97
Lens voltage (V)	6.75	6.75
Analog stage voltage (V)	−1700	−1700
Pulse stage voltage (V)	900	900
Dwell time per AMU	2ms	2ms
Scan mode	Peak hopping	Peak hopping
Sweeps/reading	25	25
Readings/replicate	20	25
Replicates	15	25
Cell gas A : CH4 (mL/min)	1.5	0.8
RP q: Ar (mL/min)	0.8	0.45