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在富燃性空气-乙炔火焰状态下测定不同钢种中铬时,存在许多共存元素干扰,尤其是铝钛的干扰最为严重,铁的负干扰变化亦相当可观。本法改用贫燃性空气-乙炔焰测定,在不必专门加入干扰抑制剂的条件下,可有效地消除钢中共存元素的干扰,结果准确,方法简单,实用效果十分理想。 一、主要仪器设备与试剂 GFU-202型原子吸收光谱仪;AS-1铬空心阴极灯。仪器工作条件:双光束吸收,平均值方式,积分时间3s,量程扩展×1;波长选择357.9nm,狭缝宽度0.1mm;灯电流6mA,负高压-270V;稍燃火焰,空气流量7.5L/min,乙炔流量1.6L/min;光束中心位于燃烧器上方9mm。 硝酸、高锰酸钾、亚硝酸钠均为分析纯。
There are many coexisting elements in the determination of chromium in different steel grades in rich air-acetylene flame state, especially the interference of aluminum-titanium is the most serious, and the variation of iron negative interference is considerable. The method uses the lean air-acetylene flame instead of the interfering inhibitor, which can effectively eliminate the interference of the coexisting elements in the steel. The result is accurate, the method is simple and the practical effect is very satisfactory. First, the main equipment and reagents GFU-202 atomic absorption spectrometer; AS-1 chromium hollow cathode lamp. Instrument operating conditions: double beam absorption, the average mode, the integration time 3s, range expansion × 1; wavelength selection 357.9nm, slit width 0.1mm; lamp current 6mA, negative high voltage -270V; slightly flame, air flow 7.5L / min, acetylene flow 1.6L / min; beam center is located above the burner 9mm. Nitric acid, potassium permanganate, sodium nitrite were of analytical grade.