Effect of radio frequency power and carrier gas flow rate on signal-to-background ratio in ICP-AES

Dependence of SBR (signal-to-background ratio) on rf power as a function of carrier gas flow rate in ICP-AES was investigated on the spectral lines of Cr I 425.435 nm and Ca I 442.673 nm as a soft analytical line, and Zn I 213.856 nm, La II 408.671 nm, Ti II 336.121 nm, Fe II 259.940 nm and Zn II 202.548 nm as a hard analytical line, respectively. In the case of the soft analytical lines, the SBRs decreased continuously with an increase in the rf power regardless of the carrier gas flow rate. On the other hand, in the case of hard analytical lines, the maximum point of the SBR appeared with an increase in the rf power when a higher carrier gas flow rate was applied. In particular, the SBR increased with an increase in the rf power on Zn II 202.548 nm at 0.60 l/min of carrier gas flow rate. Thus, the rf power and the carrier gas flow rate should be carefully selected for the hard analytical lines in order to obtain the best SBR values.