High irradiance laser ionization mass spectrometry for direct speciation of iron oxides

Abstract

A novel method has been developed that allows the direct speciation analysis of iron oxides based on a modified laser ionization orthogonal time-of-flight mass spectrometer. Time resolved mass spectra were acquired for the investigation of elemental ions and oxide ions generated by a laser ionization source. Speciation methodologies, including the identification of characteristic ions and the use of ion abundance ratios were evaluated for the differentiation of the oxides. The influence of operating parameters on the distribution of cluster ions was investigated, and their mechanism of formation discussed.

Source and mixing state of iron-containing particles in Shanghai by individual particle analysis

“…The higher number fraction of these iron oxides in Fe-containing particles, comparing with other detected particles (Fig. S3), indicates the accumulation of iron oxide clusters in Fe-containing particles (Yan et al, 2010).…”

Laser Ionization Mass Spectrometry at 55: Quo Vadis?

“…The study has shown that high correlations between the elemental concentrations and the signal intensities were achieved with limits of detection (LODs) in the 10 −7 -10 −8 mol/g range and a dynamic range of 6 orders of magnitude for most nonmetallic elements (Figure 27). The same instrument was tested for isotope ratio measurements, achieving less than 4% error for 7 molybdenum isotopes at low 10 −5 mol/g (Yu et al, 2009c), as well as used for direct speciation analysis of iron oxides (Yan et al, 2010).…”

On Applicability of a Miniaturised Laser Ablation Time of Flight Mass Spectrometer for Trace Elements Measurements

“…On the other hand, the plasma temperature increase can result in a destabilisation of clusters or even disable larger cluster formation [34]. For low laser irradiances (<10 7 W/cm 2 ), the clusters can be formed via desorption/ionisation mechanism, but at larger irradiances, plasma chemistry is essential [35,36]. When UV radiation will be used for ablation, further reduction of cluster abundances is to be expected owing to an enhancement of the rate of photodissociation processes induced by more energetic UV photons [37].…”

“…They do not follow strictly the elemental abundance distribution. The knowledge of the isotopic distribution of clusters can be helpful for conducting the quantitative control and is of considerable interest in speciation analysis [36].…”