Institute of Materia Medica, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250062, China.
Molecules. 2022 Jan 18;27(3):590. doi: 10.3390/molecules27030590.
Ligands plays an important role in the extraction procedures for the determination of cadmium in rice samples by using flame atomic absorption spectrometry (FAAS). In the present study, comparative evaluation of 10 commercially available ligands for formation of Cd(II)-ligand complex and determination of cadmium in rice samples by ultrasound-assisted dispersive liquid-liquid microextraction (UADLLME) combined with FAAS was developed. Sodium diethyldithiocarbamate (DDTC) provided a high distribution coefficient as well as a good absorbance signal, therefore DDTC was used as a ligand in UADLLME. A low density and less toxic solvent, 1-heptanol, was used as the extraction solvent and ethanol was used as the disperser solvent. In addition, the experimental conditions of UADLLME were optimized in standard solution first and then applied in rice, such as the type and volume of extractant and dispersant, pH, extraction time, and temperature. Under the optimal experimental conditions, the detection limit (3σ) was 0.69 μg/L for Cd(II). The proposed method was applied for the determination of Cd(II) in three different rice samples (polished rice, brown rice, and glutinous rice), the recovery test was carried out, and the results ranged between 96.7 to 113.6%. The proposed method has the advantages of simplicity, low cost, and accurate and was successfully applied to analyze Cd(II) in rice.
配体在使用火焰原子吸收光谱法（FAAS）测定大米样品中镉的提取程序中起着重要作用。在本研究中，对 10 种市售配体进行了比较评估，用于形成 Cd(II)-配体络合物，并通过超声辅助分散液-液微萃取（UADLLME）与 FAAS 联合测定大米样品中的镉。二乙基二硫代氨基甲酸钠（DDTC）提供了高分配系数和良好的吸光度信号，因此 DDTC 被用作 UADLLME 中的配体。使用 1-庚醇作为萃取溶剂，其密度低且毒性较小，乙醇作为分散溶剂。此外，首先在标准溶液中优化了 UADLLME 的实验条件，然后将其应用于大米中，例如萃取剂和分散剂的类型和体积、pH 值、萃取时间和温度。在最佳实验条件下，Cd(II) 的检测限（3σ）为 0.69 μg/L。该方法用于测定三种不同大米样品（精米、糙米和糯米）中的 Cd(II)，进行了回收试验，结果在 96.7%至 113.6%之间。该方法具有简单、低成本、准确的优点，并成功应用于分析大米中的 Cd(II)。
