The aim of this study was to conduct multi-elemental speciation of As(III), dimethylarsinic acid (DMA), monomethylarsenic acid (MMA), As(V) and Cr(VI) in water samples using high performance liquid chromatography coupled to inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) in a single analytical run. Chromatographic parameters, spectral interference identification, and elimination and the performance characteristics of the method were successfully optimized for quantification of As(III), DMA, MMA, As(V), Cr(VI) and Cr(III) in water samples. The percentage errors of 6.93–43.2% for identified potential interferences were eliminated by applying the inter-element mathematical correction method. The limit of detection (LOD) and limit of quantification (LOQ) of As species and Cr(VI) were varied from 0.040 to 0.298 μg L⁻¹ and 0.133–2.98 μg L⁻¹, respectively. The LOD and LOQ of total As, Cr and Pb determined using ICP-MS were ranged from 0.013 to 0.203 μg L⁻¹ and 0.045–0.675 μg L⁻¹, respectively. The accuracy of the method was confirmed by achieving the percentage recovery of 83.4% for As species, 90.2% for Cr(VI) and 110–118% for total concentrations of As, Cr and Pb using standard reference material for trace elements in water (SRM 1643f). Furthermore, the accuracy of the speciation analysis method was checked using the spiking and recovery studies and yielded percentage recoveries in the range of 78.3–95.4% for the analyte species. The quantities of species determined in water samples were in the range of 0.314–0.402 μg L⁻¹ for As(III), 0.168–0.533 μg L⁻¹ for DMA, 0.226–0.312 μg L⁻¹ for MMA, 0.191–0.459 μg L⁻¹ for As(V), 0.500–3.28 μg L⁻¹ for Cr(VI) and 0.390–12.6 μg L⁻¹ for Cr(III) in high-flow seasonal state of the river. In the low-flow seasonal state, concentrations varied from 0.314 to 0.391 μg L⁻¹ for As(III), <0.094 μg L⁻¹ for DMA, 0.315–26.7 μg L⁻¹ for MMA, 0.290–0.744 μg L⁻¹ for As(V), 0.426–5.42 μg L⁻¹ for Cr(VI) and 0.424–96.8 μg L⁻¹ Cr(III). Total concentrations of As, Cr and Pb in water samples of high-flow seasonal state ranged from 0.949 to 1.88 μg L⁻¹, 1.08–14.9 μg L⁻¹ and 0.190–33.8 μg L⁻¹, respectively. In low-flow seasonal state, the total concentrations of As, Cr and Pb in water samples varied from 1.13 to 26.5 μg L⁻¹, 3.28–97.5 μg L⁻¹ and 0.455–0.610 μg L⁻¹, respectively. The variations between analytes species and total As, Cr and Pb in seasonal states of the river were statistically insignificant (p ˃ 0.05) at a 95% confidence level except for DMA. The nonpoint sources pollution such as atmospheric deposition of dust released from coal mining, power stations, sewage effluents discharge and agricultural activities are presumably the sources of potentially toxic elements in the Mokolo River.

这项研究的目的是使用高效液相色谱-电感耦合技术对水样中的砷（III），二甲基砷酸（DMA），一甲基砷酸（MMA），砷（V）和铬（VI）进行多元素形态分析。一次分析运行中的等离子质谱联用（HPLC-ICP-MS）。成功地优化了色谱参数，光谱干扰识别和消除方法的性能特征，用于定量分析水样中的As（III），DMA，MMA，As（V），Cr（VI）和Cr（III）。通过使用元素间数学校正方法，可以消除已识别出潜在干扰的6.93–43.2％百分比误差。As物种和Cr（VI）的检出限（LOD）和定量限（LOQ）在0.040至0.298μgL之间变化^-1和0.133-2.98μgL ^-1。使用ICP-MS测定的总砷，铬和铅的LOD和LOQ分别为0.013至0.203μgL ^-1和0.045-0.675μgL ^-1。使用标准参考物质测定水中的痕量元素（As（As），Cr（VI）的总回收率分别为80.2％，Cr（VI）的90.2％和As，Cr和Pb的总浓度为110–118％（％， SRM 1643f）。此外，使用加标和回收率研究检查了形态分析方法的准确性，得出分析物种类的回收率百分比为78.​​3–95.4％。在水样中测定的物种数量在0.314–0.402μgL ^-1的范围内对As（III），0.168-0.533微克大号^-1为DMA，0.226-0.312微克大号^-1为MMA，0.191-0.459微克大号^-1对As（V），0.500-3.28微克大号^-1为铬（VI ）和在河流高流量季节状态下的Cr（III）0.390–12.6μgL ^-1。在低流量的季节性状态，浓度变化范围为0.314到0.391微克大号^-1对As（III），<0.094微克大号^-1为DMA，0.315-26.7微克大号^-1为MMA，0.290-0.744微克大号^-1对于As（V），Cr（VI）为0.426–5.42μgL ^-1，对于Cr（III）为0.424–96.8μgL ^-1 Cr（III）。高流量季节性水质样品中As，Cr和Pb的总浓度范围为0.949至1.88μgL^-1，1.08-14.9微克大号^-1和0.190-33.8微克大号^-1，分别。在低流量的季节性状态，总浓度砷，铬和铅的水样中的变化从1.13到26.5微克大号^-1，3.28-97.5微克大号^-1和0.455-0.610微克大号^-1分别。除DMA以外，在95％的置信度下，河流季节性状态中分析物种类与总As，Cr和Pb之间的变化在统计学上不显着（p˃0.05）。非点源污染，例如从煤矿，发电厂排放的尘埃在大气中的沉积，发电厂的污水排放和农业活动，可能是莫科洛河中潜在有毒元素的来源。