A Rapid Acid Digestion Technique for the Simultaneous Determination of Bromine and Iodine in Fifty‐Three Chinese Soils and Sediments by ICP‐MS

Abstract

Bromine and iodine are important tracers for geochemical and environmental studies. In this study, a rapid acid digestion (HNO3 + HF) with ammonia dilution for the simultaneous determination of bromine and iodine in soils and sediments using ICP‐MS was developed. The recoveries of Br and I were controlled by the synergic effect of temperature and time. It took only 15 min at 140 °C for the complete recovery of Br and I in sediment (GSD‐2) and soil (GSS‐24) reference materials, which is a process that needs 2–6 h at 90 °C. A serious loss of Br and I was found at a higher digestion temperature of 190 °C. A 5% v/v NH4OH dilution effectively eliminated the memory effects and stabilised the signals of Br and I. Moreover, ammonia dilution also avoided the corrosiveness of HF on the sample introduction system and torch of ICP‐MS. Tellurium is a more suitable internal standard element than In in the ammonia medium. To avoid the adsorption of residues of dissolution on Te, addition of Te should be carried out after centrifuging the solution. The developed method was successfully applied to determine Br and I in fifty‐three Chinese soil and sediment reference materials. This simple method shows great potential for the rapid determination of Br and I in large batches of geological and environmental samples commonly analysed for mineral exploration and environmental geochemistry studies.

Challenges and trends for halogen determination by inductively coupled plasma mass spectrometry: A review

“…64 Although fluorine is less prone to this issue, 22 chlorine, bromine, and iodine can suffer major memory effects depending on the characteristics of digests and washing solution. 22,52,53,65 Furthermore, the volume of the spray chamber can influence the extent of memory effects, as spray chambers with lower capacity require shorter washing times. 66 The material of the spray chamber and tubing can also contribute to memory effects (e.g.…”

“…66 Regarding washing solutions, several studies have used alkaline solutions such as NH 4 OH and tetramethylammonium hydroxide (TMAH) that have been also used as a medium to prepare the standard calibration solutions. 22,49,52,[64][65][66][67][68][69][70][71][72] It has been reported that, when using 5% HNO 3 as a washing solution, 200 s were necessary for iodine counts to be reduced to 10% of their original value. When using 5% NH 4 OH as washing solution, only 20 s were necessary for iodine counts to return to the original value.…”

“…When using 5% NH 4 OH as washing solution, only 20 s were necessary for iodine counts to return to the original value. 65 Another study found that it took 120 s for halogen signal intensities to be reduced to their original value when using 5% NH 4 OH as washing solution. 22 This is probably due to the formation of volatile halogen species, such as X 2 or HX (X = bromine or iodine), in an acidic medium, while the analytes remain in their ionic forms, which are more stable, when in an alkaline solution.…”

“…47,52,70,73 In this sense, several studies have used alkaline solutions such as NH 4 OH and TMAH as washing solutions for halogen determination by ICP-MS, as well as a medium to prepare the standard calibration solutions. 22,49,52,[64][65][66][67][68][69][70][71][72] Alternatively, the use of a 2% alcohol acidic solution 74 Another concern is regarding analyte stability during ICP-MS determination. Signal suppression and analyte losses when using acidic solutions can occur, especially for iodine.…”

Geostandards and Geoanalytical Research Bibliographic Review 2018

“…Recently, there have been studies to fill this gap (e.g., Marks et al ). In 2018, there are two substantial publications providing data for halogens: Kendrick et al () publish data for F, Cl, Br and I in thirteen RMs mainly from the USGS, NIST and GSJ, whereas He et al () present Br and I values for fifty‐three Chinese RMs.…”