Institute of Chemistry, University of Bialystok, K. Ciołkowskiego 1K, 15-245 Bialystok, Poland.
Molecules. 2019 Mar 25;24(6):1172. doi: 10.3390/molecules24061172.
The aim of this work was to study by a hyphenated HPLC-ICP MS technique the chromium species released during alkaline extraction of various soils collected from a contaminated area of an old tannery. An ultrasound-assisted extraction procedure using 0.1 mol L Na₂CO₃ solution was developed for the release of chromium species from the soil. The chromium species in the soil extracts were separated on a C₈ column using EDTA and TBAH solution as a mobile phase. The use of an ICP-QQQ MS spectrometer in tandem mass configuration (MS/MS) combined with an octopole reaction system (ORS³) pressurized with helium allows one to eliminate spectral interferences during Cr determination in the soil extracts. The detection limit of the procedure was 0.08 µg L for Cr(III) and 0.09 µg L for Cr(VI) species. The trueness of the IP RP HPLC-ICP MS method was proved by an analysis of CRM 041 and CRM 060. The advantage of the proposed method is the analysis of soil extracts without their preliminary neutralization, which limits the losses of Cr(VI) due to the reduction process. The analysed soils mainly contained chromium in immobile forms (94.6⁻98.5% of the total Cr content). In all alkaline soil extracts mostly the Cr(VI) form was found, but in the extract of organic soils Cr(III) was also present. This arose from the reduction of Cr(VI) species by organic matter (humic acids) and Fe(II). The amount of formed Cr(III) species was dependent on the type of soil (content of organic matter, Mn and Fe) and its moistness. For the first time, the presence of neutral and non-polar chromium fractions in the soil extracts was also demonstrated. It was found that reliable speciation analysis results could be obtained for mineral soils.
本工作旨在采用 HPLC-ICP-MS 联用技术研究从旧制革厂污染区采集的不同土壤在碱性提取条件下释放的铬形态。建立了超声辅助提取法，采用 0.1mol/LNa₂CO₃溶液提取土壤中的铬形态。采用 EDTA 和 TBAH 溶液作为流动相，在 C₈ 柱上分离土壤提取物中的铬形态。采用 ICP-QQQ MS 串联质谱仪（MS/MS）结合氦气加压的八极反应系统（ORS³），可以消除土壤提取物中 Cr 测定时的光谱干扰。该方法的检测限为 0.08μg/L 的 Cr(III)和 0.09μg/L 的 Cr(VI)。通过对 CRM 041 和 CRM 060 的分析，证明了 IP RP HPLC-ICP MS 方法的准确性。该方法的优点是无需对土壤提取物进行预先中和，从而减少了 Cr(VI)因还原过程造成的损失。所分析的土壤主要含有固定形态的铬（总铬含量的 94.6⁻98.5%）。在所有碱性土壤提取物中，主要发现了 Cr(VI)形态，但在有机土壤提取物中也存在 Cr(III)。这是由于有机物质（腐殖酸）和 Fe(II)将 Cr(VI)还原。形成的 Cr(III)形态的量取决于土壤类型（有机物、Mn 和 Fe 的含量）及其湿度。首次证明了土壤提取物中存在中性和非极性铬形态。研究发现，对于矿物土壤，可以获得可靠的形态分析结果。
