Department of Chemistry, Faculty of Science and Technology, Thammasat University, Pathumthani, 12120, Thailand.
Department of Chemistry, Faculty of Natural Sciences, National University of Laos, P. O. Box 7322, Vientiane, Lao PDR.
Sci Rep. 2021 Nov 29;11(1):23073. doi: 10.1038/s41598-021-02516-4.
In this study, we customized magnetic sorbents by functionalizing silica coated magnetite with octadecyl(C)silane (FeO@SiO@C). This sorbent was intended for the determination of trace orthophosphate (o-PO) in unpolluted freshwater samples. The o-PO was transformed to phosphomolybdenum blue (PMB), a known polyoxometalate ion. Then the PMB were coupled with cetyl trimethyl ammonium bromide (CTAB), cationic surfactant, in order to hydrophobically bound with the FeO@SiO@C particles through dispersive magnetic solid-phase extraction (d-MSPE) as part of sample preconcentration. The PMB-CTAB-magnetic particles are simply separated from the aqueous solution by the external magnet. The acidified ethanol 0.5 mL was used as PMB-CTAB eluent to produce an intense blue solution, which the absorbance was measured using a UV-Vis spectrophotometer at 800 nm. The proposed method (employing 2 mg of FeO@SiO@C) yielded an enhancement factor of 32 with a linear range of 1.0-30.0 µg P L. Precision at 6.0 µg P L and 25.0 µg P L were 3.70 and 2.49% (RSD, n = 6) respectively. The lower detection limit of 0.3 µg P L and quantification limit of 1.0 µg P L allowed trace levels analysis of o-PO in samples. The reliability and accuracy of the proposed method were confirmed by using a certified reference material. Our method offers highly sensitive detection of o-PO with simple procedures that can be operated at room temperature and short analysis time.
在这项研究中，我们通过用十八烷基（C）硅烷（FeO@SiO@C）对硅涂层磁铁矿进行功能化来定制磁性吸附剂。该吸附剂用于测定未污染淡水样品中的痕量正磷酸盐（o-PO）。o-PO 被转化为磷钼蓝（PMB），一种已知的多金属氧酸盐离子。然后，PMB 与十六烷基三甲基溴化铵（CTAB），阳离子表面活性剂结合，通过分散磁固相萃取（d-MSPE）将其与 FeO@SiO@C 颗粒疏水结合，作为样品预浓缩的一部分。PMB-CTAB-磁性颗粒通过外部磁铁从水溶液中简单分离。酸化的 0.5 mL 乙醇用作 PMB-CTAB 洗脱液，产生强烈的蓝色溶液，使用紫外-可见分光光度计在 800nm 处测量其吸光度。该方法（使用 2mg 的 FeO@SiO@C）得到 32 的增强因子，线性范围为 1.0-30.0µg P L。在 6.0µg P L 和 25.0µg P L 时的精密度分别为 3.70%和 2.49%（RSD，n=6）。0.3µg P L 的检测限和 1.0µg P L 的定量限允许对样品中的 o-PO 进行痕量分析。通过使用认证参考材料证实了该方法的可靠性和准确性。我们的方法提供了具有高灵敏度的 o-PO 检测，具有简单的程序，可在室温下操作，分析时间短。
