Determination of ultra-trace amounts of Fe in AgNO 3 solutions by means of isotope dilution analysis applying an inductively coupled plasma mass spectrometer equipped with a dynamic reaction cell

Abstract

The development of an ICP-MS method for the determination of ultra-trace amounts of Fe in AgNO(3) solutions using isotope dilution for calibration is described. AgNO(3) solutions are used as raw materials in the production of traditional photographic materials, and it is known that contamination with metal traces can influence the quality of the films thus produced. After adding an appropriate amount of an (54)Fe-enriched spike and permitting isotopic equilibration to take place, Ag was selectively removed from the solutions by precipitation as AgBr. Although to some extent, co-precipitation of Fe is possible under the given circumstances, an incomplete recovery of the analyte element did not affect the accuracy of the results, owing to the use of isotope dilution for calibration. NH(3) was used as a reaction gas in a quadrupole-based ICP-MS instrument, equipped with a dynamic reaction cell (DRC), providing interference-free measurement of the (54)Fe/(56)Fe ratio. The limit of detection (LOD) obtained using this procedure was approximately 0.01 micro g g(-1). This is an excellent value in comparison with the detection limit obtained with the more traditional approach: sample dilution and external calibration with a Fe standard solution (LOD ~1 micro g g(-1)). To validate the method, recovery experiments were carried out. In all instances, a quantitative recovery was established. Finally, the method was applied to the analysis of AgNO(3) solutions. A large variation in Fe concentration was observed. Depending on the Fe content in the samples, relative standard deviations typically ranged between 1 and 14%.

Determination of Total Silicon and SiO2 Particles Using an ICP-MS Based Analytical Platform for Toxicokinetic Studies of Synthetic Amorphous Silica

“…If trace concentrations of Si are to be determined, any sample contamination during the whole analytical procedure is a source of bias and results in the increase of the LoD; on the other hand, the LoD can be improved by reducing background noise and ensuring that the contribution from method blanks is low and stable [31][32][33]. When the decontamination procedure described in Section 2.3.1 was applied, Si concentration in digestion blanks decreased by a factor of~10 ( Figure 2) and the variability of Si background associated with labware contamination or carryover effects from previous samples was reduced to negligible levels.…”

Analysis of twenty five impurities in uranium matrix by ICP-MS with iron measurement optimized by using reaction collision cell, cold plasma or medium resolution

“…Different gases were tested to try to overcome the 40 Ar 16 O þ interference on 56 Fe þ in order to improve the detection limit in HNO 3 solution and also for trace analysis in uranium: CH 4 [26], NH 3 [34,36] and He [44].…”

“…Iron measurements by ICP-MS with a collision and/or reaction cell have been performed on various matrices and instruments. Gases such as CH 4 , NH 3 , N 2 O, H 2 , H 2 in He have been tested to resolve the 40 Ar 16 O þ / 56 Fe þ interference and achieve the lowest detection limit [26,[34][35][36][37].…”

Use of single-collector and multi-collector ICP-mass spectrometry for isotopic analysis

“…Balcaen et al used isotope dilution for quantification of trace amounts of Fe in highly concentrated AgNO 3 solutions, used as starting material in the photographic industry. 80 In order to avoid a high dilution factor and the corresponding deterioration of the LOD, selective precipitation of the matrix element as AgBr was opted for. The effect of coprecipitation of Fe on the final result was counteracted by the use of isotope dilution, whereby the 54 Fe spike was added prior to addition of highly pure HBr.…”