Abstract：
A new and accurate method using resin enrichment of Ga, combined with isotope dilution, was developed to determine its dissolved concentrations in natural waters. The extraction properties of Chelex-100, Nobias Chelate PA-1, and Presep® PolyChelate resins for Ga from river water and seawater were compared. Experiments were conducted to determine the optimal pH range, capacity to eliminate matrix and interference, extraction and elution times, and ideal quantity of resin beads. The Chelex-100 resins were determined to be inferior to the other resins in their ability to remove the matrix and interference. The properties of Nobias Chelate PA-1 and Presep® PolyChelate were comparable, whereas Presep® PolyChelate resins were ultimately chosen for sample analysis owing to their wide range for extracting Ga at low pHs compared to Nobias Chelate PA-1 resins. The optimal isotope dilution conditions for Ga concentration measurements in natural water are discussed. The procedural blank of the method was 0.42 ± 0.18 pmol/kg (N = 12, 1 SD) and the detection limit was 0.6 pmol/kg. Intercalibration samples of GS were analyzed, with results of 41.6 ± 1.06 pmol/kg (N = 6, 1 SD), which agreed with previously reported data. Other intercalibration samples (GSP, GSC, NASS-6, NASS-7, SAFe D1, and SAFe D2) were also measured. The Ga, sampled using the contamination-free X-Vane method and conventional CTD rosette samplers, were compared and showed no statistical difference. Ga concentrations in different natural waters were determined. The Ga concentrations in rainwater were extremely low, whereas those in river water and seawater were in good agreement with existing knowledge.
摘要：
一种使用树脂富集Ga的新的准确方法，结合同位素稀释，用于确定其在天然水中的溶解浓度。比较了Chelex-100，Nobias螯合物PA-1和Presep®PolyChelate树脂对河水和海水中Ga的提取性能。进行实验以确定最佳pH范围，消除矩阵和干扰的能力，提取和洗脱时间，和理想的树脂珠的数量。确定Chelex-100树脂在去除基质和干扰的能力方面不如其他树脂。Nobias螯合物PA-1和Presep®PolyChelate的性质相当，而Presep®PolyChelate树脂最终选择用于样品分析,因为与Nobias螯合物PA-1树脂相比,它们在低pH下提取Ga的范围宽。讨论了天然水中Ga浓度测量的最佳同位素稀释条件。该方法的程序空白为0.42±0.18pmol/kg（N=12，1SD），检出限为0.6pmol/kg。分析了GS的校准样本，结果为41.6±1.06pmol/kg（N=6，1SD），与先前报告的数据一致。其他相互校准样本(GSP，GSC,还测量了NASS-6，NASS-7，SAFeD1和SAFeD2）。Ga,使用无污染的X-Vane方法和常规CTD花环采样器采样，进行比较，无统计学差异。测定了不同天然水域中的Ga浓度。雨水中的Ga浓度极低，而河水和海水中的那些与现有知识非常吻合。
