Ultrasonic nebulization and arsenic valence state considerations prior to determination via inductively coupled plasma mass spectrometry

Differences in sensitivity between As(iii) and As(v) measured by inductively coupled plasma spectrometry and the factors affecting the incoherent molecular formation (IMF) effect in the plasma

“…7 Some studies on sensitivity differences between As(III) and As(V) were also reported by other groups. Creed and co-workers reported that the As(III) response was suppressed approximately 20% relative to As(V) when they were determined by ICP-OES with an ultrasonic nebulizer (USN), 8,9 whereas Yu and co-workers reported that As(V) was about 8% more sensitive than As(III) by ICP-OES even when a pneumatic nebulizer was installed on an instrument. 10 Budi c reported on the signal behaviors of As and Se species when they were determined by ICP-OES with an ultrasonic nebulizer, 11 and Gammelgaard and co-workers described the signal characteristics of Se compounds when they were determined by ICP-MS with both ultrasonic and cross flow nebulizers.…”

Sulfate and sulfide sulfur isotopes (δ 34 S and δ 33 S) measured by solution and laser ablation MC-ICP-MS: An enhanced approach using external correction

“…In addition to the measured isotopic fractionation potentially related to the valence state of an analyte, the reduction in the sensitivity (ion transfer) for As by ICP-optical emission spectroscopy (OES) and ICP-MS relative to the oxidation state of As +3 and As +5 have also been reported (Larson and Stürup, 1994;Creed et al, 1995;Yu et al, 2006). Yu et al (2006) reported a difference of 8% in signal response between As +3 and As +5 when using ICP-OES and similar results when using an ICP-MS, and within error to the accepted value when oxidizing the standard solution to As +5 .…”

IC-ICP-MS and IC-ICP-HEX-MS determination of arsenic speciation in surface and groundwaters: preservation and analytical issues

“…Such matrix-dependent sensitivities of the order of 10-20% have been observed by Polya et al (1998), albeit with the use of a USN, which would tend to accentuate such problems compared to the use of a CGN. Creed et al (1995) noted that the use of an ultrasonic nebulizer (USN) resulted in significant differences in the sensitivity forAs(III) and As(V) by ICP-MS analysis. The As(III) signal was found to be suppressed by -20% compared to the signal for an equivalent concentration of As(V).…”

“…Such effects may be eliminated by quantitatively converting all the arsenic to one or other species prior to introduction to the nebulizer. Creed et al (1995) used treatm ent with 1 mg/l sodium hypochlorite, whilst Lythgoe et al (1999) found that mixing the sample solution prior to nebulization with a post column reaction (PCR) solution containing transition metals at 100 mg/l concen trations was effective at suppressing species fractionation in the USN/MDS, presumably by oxidizing As and Se to As(V) and Se(VI), respectively. Alternatively, the use of a CGN instead of a USN appears to minimize these fractionation effects.…”