Multivariate Optimization of an Axially‐Viewed Inductively Coupled Plasma Multichannel‐Based Emission Spectrometer for the Analysis of Environmental Samples

Abstract

An experimental design procedure was applied to optimize the operating conditions of an axially-viewed inductively coupled plasma emission spectrometer instruments equipped with echelle optics with cross dispersion and charge transfer device. The multivariate effect of carrier gas flow rate and r.f. power on several analytical figures was investigated and discussed. Both ultrasonic and pneumatic nebulization were used. For the final choice of the optimum, different criteria were taken into account, mainly plasma robustness, instrumental precision, analyte and background net emission, detection limits and signal-to-background ratios. It was found that the use of moderate power (1100W) and mean carrier gas flow rate (0.75 L/min) allows to obtain sufficient plasma robustness, satisfactory precision, and excellent signal-to-background ratios and limits of detection, favorable for ultratrace element determinations in environmental matrices.

Effect of operating conditions on excitation temperature and electron number density in axially-viewed ICP-OES with introduction of vapours or aerosols

“…By increasing the carrier gas flow rate from 0.5 to 1.2 L min À1 both excitation temperature and Mg ratio increased, passing through a maximum (at 0.7-0.85 L min À1 , depending on the power), and then decreased. Similar trends have already been reported in literature 20,34 and seem to indicate that a minimum amount of solvent reaching the ICP source is necessary in order to improve its thermal conductivity. However, a further increase in the carrier gas flow rate results in a shorter residence time because of the higher speed of the gas flowing towards the source.…”

Inductively coupled plasma optical emission spectrometry with axially viewed configuration: an overview of applications

“…Factorial designs are proposed in several works for optimization of operating conditions of axially viewed systems, leading to bidimensional graphs with information about interactions in instrumental parameters. [63][64][65] Equations could be established for several elements, allowing the proper adjustment of nebulizer gas flow rate in order to improve analytical signals. The work evaluated the efficiency of a decomposition procedure performed in a focused-microwave oven with six reaction vessels Samples were decomposed in a cavity-microwave oven using HNO 3 + H 2 O 2 .…”

Multivariate study in chemical vapor generation for simultaneous determination of arsenic, antimony, bismuth, germanium, tin, selenium, tellurium and mercury by inductively coupled plasma optical emission spectrometry

“…The ICP-OES parameters were chosen in order to have sufficient plasma robustness and to maximize the signal to background ratios. 29,30 Plasma excitation conditions were monitored by measuring the Pb II 220.353 nm/Pb I 217.000 nm ratio, as discussed below. The selection of wavelengths is reported in Table 2.…”

“…Similar trends were observed when studying the effect of the nebulizer gas flow rate on MgR with both pneumatic and ultrasonic nebulization. 30,38,39 These trends seem to indicate that a minimum amount of solvent, in the case of pneumatic or ultrasonic nebulization, and of vapors (e.g. hydrogen) in the case of CVG reaching the ICP source is necessary in order to improve its thermal conductivity.…”