Ion chromatography coupled to mass spectrometry as a powerful technique for halogens and sulfur determination in egg powder and its fractions

A simple, low cost and fast sample preparation method for fluorine determination by ISE in leguminous seeds and oilseeds

This work presents the first report of the application of microwave-induced combustion in disposable vessels (MIC-DV) as a simple and fast sample preparation step for fluoride determination by ion-selective electrode (ISE) in leguminous seeds and oilseeds samples. Several experimental conditions of MIC-DV were evaluated, such as sample mass, absorbing solution, volume of combustion igniter, purging time with oxygen, and the use of successive combustion cycles. The accuracy of MIC-DV/ISE method was evaluated by comparing the results obtained by microwave-induced combustion and determination by ion chromatography, with agreements ranged from 94 to 106%. The method allowed to achieve relatively low limits of quantification (8.3 to 16 µg g-1) comparing to AOAC method (40 µg g-1), besides the use of small amounts of reagents, less handling of digests, making the method greener and with portable features comparing to other methods.

Determination of Halogens by Ion Chromatography in Edible Mushrooms after Microwave-Induced Combustion for Sample Preparation

In this study, the microwave-induced combustion (MIC) method was evaluated for the sample preparation of the most consumed mushroom species in Brazil (Champignon, Shiitake, and Shimeji) and further halogen determination by ion chromatography (IC). For this, sample mass, combustion aid mass, and absorbing solution (H₂O and 50 mmol·L^-1, 100 mmol·L^-1, or 150 mmol·L^-1 NH₄OH) were evaluated. Bromine and iodine concentrations, determined by IC, were lower than the limits of detection (LODs, Br: 6 mg·kg^-1 and I: 24 mg·kg^-1). Inductively coupled plasma mass spectrometry (ICP-MS) was also used for Br and I determination, and the LODs were lower (Br: 0.066 mg·kg^-1 and I: 0.014 mg·kg^-1) than those obtained by IC. Concentrations of Cl, obtained by IC, ranged from 523 mg·kg^-1 to 13053 mg·kg^-1 with LOD of 40 mg·kg^-1. In turn, Br and I concentrations, obtained by ICP-MS, ranged from 2.49 mg·kg^-1 to 5.50 mg·kg^-1 and from <0.014 mg·kg^-1 to 0.047 mg·kg^-1, respectively. Fluorine concentrations, determined by IC, were always lower than LOD (23 mg·kg^-1). The trueness of the proposed methods was evaluated by recovery tests using standard solutions and a reference material (RM NIST 8435). When using the standard solution, recoveries ranged from 95% to 103% for halogen determination by IC and from 105% to 109% for Br and I determination by ICP-MS. When using the RM, recoveries of 102% for Cl by IC and of 87% and 86% for Br and I by ICP-MS, respectively, were obtained.