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This paper describes experiments aimed at discriminating the different effects of ion energy in collision/reaction cell ICP-MS. It is demonstrated that the input ion energy, as determined by the plasma offset potential and ion energy distribution, is a key determinant of cell reactivity and this is termed the ion kinetic energy effect (IKEE). The ion kinetic energy is varied by alteration of the potential difference between the plasma and the hexapole cell. The plasma offset potential and ion energy distribution are not accurately known but are inferred from ''stopping curves'' produced by varying the pole bias of the quadrupole analyser. Kinetic energy discrimination (KED), where the difference in bias potentials between the quadrupole mass analyser and the hexapole cell is exploited to reject slow cell-formed ions, is shown to be a different effect. It can be used to change the relative levels of polyatomic ions arriving at the detector. The influence of IKEE and KED on the levels of plasma and analyte oxide (MO 1 ) ions and on the 21 (H 3 O) 1 / 36 Ar 1 reactivity indicator ratio are considered. It is shown that IKEE can be used to influence the reactive attenuation of argide ions and the production of MO 1 in the cell. KED is shown to preferentially reject cell-formed MO 1 from the mass analyser.

The measurement of mercury vapour in ambient air is required in order to ensure the quality life of the general public. New legislation introduced recently by the European Commission has mandated that sampling and analysis be performed in situ at monitoring sites, and that mass concentration of mercury vapour in ambient air is determined within a maximum uncertainty. This paper presents a novel and innovative automatic method for such in situ measurements of mercury vapour in ambient air using atomic fluorescence spectrometry, where calibration, sampling and analysis are all performed fully automatically without manual intervention. A robust measurement equation and uncertainty budget for this automatic method is developed, and the overall relative expanded uncertainty for an exemplar measurement has been found to be 21%, well below the target expanded uncertainty of 50% set by the European Commission for these measurements. The uncertainty of a semi-automatic method (automatic sampling and analysis, but manual calibration) has also been assessed, and compared with the uncertainty of the novel automatic method, and the uncertainty of a manual (remote sampling and manual calibration and analysis) method presented in a previous study.

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Correct handling and preservation of water samples is crucial to ensure their integrity for arsenic speciation measurements. ISO TS 19620:2018 is a method for the determination of arsenic(III) and arsenic(V)...

The manual and semi-automatic methods for the measurement of total gaseous mercury in ambient air have been compared in a field trial for the first time. The comparison results have shown that whilst the expected random scatter is present, there was no significant systematic bias between the two methods, whose operational differences have also been outlined and analysed in this work. Furthermore it has been observed that because variation in instrument sensitivity is largely random in nature there is little effect on the results of the comparison if the period between instrument calibrations is altered. When the manual and semi-automatic methods are compared according to guidelines produced by the European Commission the results presented here, taken together with other supporting evidence, strongly suggest that the two methods are equivalent.

Abstract. Atmospheric mercury speciation is of paramount importance for understanding the behavior of mercury once it is emitted into the atmosphere as gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM) and particulate-bound mercury (PBM). GOM and PBM can also be formed in the atmosphere; their sampling is the most problematic step in the atmospheric mercury speciation. GOM sampling with speciation traps composed of KCl sorbent materials and KCl trapping solutions are commonly used sampling methods, although the research conducted with them at ambient air concentrations is limited. The results of the specificity test demonstrated that the KCl sorbent traps are highly specific when using new traps, while their specificity drops dramatically when they are reused. The results of the stability test indicated that the highest Hg2+ losses (up to 5.5 % of Hg2+ loss) occur when low amounts of Hg2+ (< 1 ng) are loaded, due to a reduction of Hg2+ to Hg0. KCl trapping solutions have also been considered as a selective trapping media for GOM in atmospheric samples. A dimensionless Henry law constant was experimentally derived and was used to calculate the solubility of elemental Hg in KCl solution. The degree of GEM oxidation was established by purging elemental Hg calibration gas into a KCl solution and determining the GOM trapped using aqueous-phase propylation liquid–liquid extraction and gas chromatography–atomic fluorescence spectrometry (GC-AFS) measurement. A positive GOM bias was observed due to the solubility and oxidation of GEM in KCl trapping solutions, strongly suggesting that this approach is unsuitable for atmospheric mercury speciation measurements.