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氟离子电极用于测定矿物、岩石,土壤中的氟已有大量报道。对于测定中的关键问题——铝的掩蔽,前人作过大量工作。应用最广泛的掩蔽剂是钛铁试剂,柠檬酸盐及磺基水杨酸—EDTA。就掩蔽效果而论,当推钛铁试剂为好,可惜该试剂价格贵,用量又较大。磺基水杨酸—EDTA对于微量氟的测定又不适宜。有的人在碱熔水浸后加入酸或碳酸氢钠。降低溶液pH值,使铝沉淀分离。大量酸或碳酸氢钠的加入及大量沉淀产生对分析也觉不便。我们从化探样品数量多的特点出发,选用了柠檬酸钠作络合物的缓冲液,并试验了相应的条件,制定了一个简便、成本不高、准确度符合要求的分析方法。适用于一般岩石、土壤中0.01％以上氟的分析。
Fluoride ion electrode for the determination of minerals, rocks, soil fluorine has been a lot of reports. For the determination of the key issues - aluminum masking, predecessors have done a lot of work. The most widely used masking agents are ilmenite, citrate and sulfosalicylic-EDTA. In terms of masking effect, when the push titanium agent is good, but the reagent is expensive, the dosage is larger. Sulfosalicylic acid-EDTA for the determination of trace fluorine is not appropriate. Some people add acid or sodium bicarbonate after alkali water immersion. Lower the pH of the solution to precipitate the aluminum. The addition of a large amount of acid or sodium bicarbonate and the precipitation of a large amount also cause inconvenience to the analysis. Based on the large number of geochemical samples, we selected sodium citrate as complex buffer and tested the corresponding conditions to develop a simple, low-cost and accurate analytical method that meets the requirements. For general rock, soil analysis of more than 0.01% fluorine.