离子色谱法测定蚀刻槽废氢氟酸中的六氟硅酸

建立了一种新的检测蚀刻槽废氢氟酸中六氟硅酸的离子色谱方法。色谱柱为Metrosep A Supp 7阴离子交换柱,流动相为3.2 mmol/L碳酸钠-1.0 mmol/L碳酸氢钠,流速为0.7 m L/min。六氟硅酸经过抑制型电导检测器后进行衍生化反应,在360 nm波长下用紫外检测器检测。六氟硅酸的线性范围为2.4~120 mg/L,相关系数r2大于0.999,定量限为0.24 mg/L,平均加标回收率为97.2%。本方法还可以同时利用电导检测器检测废氢氟酸中的氢氟酸、醋酸、盐酸、硝酸、磷酸和硫酸的含量。该方法快速、准确,适用于蚀刻槽液中六氟硅酸的检测。

Determination of hexafluorosilicic acid in the wasted hydrofluoric acid in the etching bath solution with ion chromatography

A new method for the determination of the hexafluorosilicic acid in the wasted hydrofluoric acid by ion chromatography (IC) with UV-Vis (ultraviolet-visible) detector after post column reaction was investigated. The wasted hydrofluoric acid was produced in the silicon etching bath. The separation was achieved on a Metrosep A Supp 7 column with 3.2 mmol/L sodium carbonate and 1.0 mmol/L sodium bicarbonate at a flow rate of 0.7 mL/min. In this thesis, the derivatization reaction temperature, reagent adding rate and the UV detector wavelength were studied. The other mineral acids in the etching bath, such as hydrofluoric acid, chloric acid, nitric acid, phosphoric acid, acetic acid and sulfuric acid also could be determined in the same time by the suppressed conductivity detection. The method showed that hexafluorosilicic acid had good linearities in the range of 2.4-120 mg/L. The average recovery of the hexafluorosilicic acid in the real sample was 97.2%. The limit of quantification of hexafluorosilicic acid was 0.24 mg/L. The method is accurate, fast and suitable for the determination of hexafluorosilicic acid in the etching bath solution.