Table 5 Operating conditions and analytical lines for the SPECTRO CIROS ^CCD ICP optical emission spectrometer

Generator

Free-running 27.12 MHz operated at 1400 W

Plasma torch

Axial viewing, torch positioning (mm) X = - 3.9, Y = + 3.6, Z = + 2.6.

Argon flow rates:

Outer gas 12 l/min

Intermediate gas 0.6 l/min

Nebulizer gas 1 l/min

Sample introduction system

Four channels peristaltic pump, K2 cross-flow nebulizer, double pass Scott type spray chamber, 2 ml/min sample uptake rate

Polychromator

160 – 600 nm double grating Paschen-Runge mounting, chamber filled with Ar

Detector

22 CCDs

Data processing

Background correction: linear and square two points models, best SNR strategy, integration time 48 s and three successive measurements for each sample.

Analytical wavelengths

Ag 328.068 nm; Cd 214.438 nm; Co 228.615 nm; Cr 267.716 nm; Cu 324.754 nm; Ni 305.082 nm; Pb 220.351 nm; Zn 213.856