Feasibility of microwave‐induced combustion combined with inductively coupled plasma mass spectrometry for bromine and iodine determination in human nail

• Published in: Rapid communications in mass spectrometry 2020-09, Vol.34 (S3), p.e8675-n/a
• Main Authors: Novo, Diogo La Rosa, Henn, Alessandra Schneider, Flores, Erico Marlon Moraes, Mesko, Marcia Foster
• Format: Article
• Language: English
• Subjects: Ammonium hydroxide; Analytical chemistry; Biological samples; Bromine; bromine determination; Carbon content; Chemical reduction; Combustion; Emission spectroscopy; ICP‐MS; Inductively coupled plasma mass spectrometry; Iodine; iodine determination; Mass spectrometry; Mathematical analysis; Methods; Physiology; Reagents; sample preparation; Scientific imaging; Selectivity
• ISSN: 0951-4198; 1097-0231
• DOI: 10.1002/rcm.8675

Rationale Bromine and iodine have important physiological functions; however, in inadequate concentration, they can also cause several physiological problems. Their mobility assessment in human organisms through biological sampling may help clarify some doubts related to metabolic routes, which are still not well elucidated. In this context, a suitable analytical method for this purpose should be developed. Methods An analytical method for determining ultratrace levels of bromine and iodine in human nail samples was developed. Inductively coupled plasma mass spectrometry (ICP‐MS) using a conventional nebulization system was immediately chosen as the determination tool because of its powerful sensitivity and selectivity. Sample preparation methods including microwave‐induced combustion (MIC), microwave‐assisted extraction, and microwave‐assisted digestion were evaluated. The compatibility of the final solutions with ICP‐MS analysis was considered while the method was developed. Results MIC was chosen as the most suitable method for the sample preparation for determining the levels of bromine and iodine in human nail samples using ICP‐MS. Unlike other sample preparation methods, this one fully eliminated interferences related to the carbon content and memory effects. Sample masses up to 100 mg were efficiently digested, and the analytes were quantitatively absorbed using only 50 mmol L−1 NH4OH solution. Recoveries ranged from 93% to 102%, and the relative standard deviation was < 8%. Conclusions The proposed analytical method presents important characteristics for routine analysis. It allows ultratrace determination even when low sample masses are used because of the low blank values, reduced volume of reagents, and powerful detectability using ICP‐MS.