根据二价铁与邻菲啰啉显色反应的原理,试验将粉末状的氨基磺酸、邻菲啰啉、盐酸羟胺和乙酸钠依次按0.2,0.003,0.03,0.3 g的比例充分混匀后,用压片机在5 MPa压力下压制成直径为10 mm,厚度为0.3~0.4 cm的试剂片,专用于环境水体中铁的现场快速检测。使用时,于10 mL水样中投入试剂片一片,摇动溶液待试剂片溶解完全后5 min,在波长510 nm处测量其吸光度。用铁标准溶液制作工作曲线,曲线的线性范围为0.2~4.0 mg·L-1。方法的检出限(3σ)为0.07 mg·L-1。对1.5 mg·L-1铁标准溶液进行6次重复测定,计算得其相对标准偏差为0.57%。应用所提出的方法测定了3种水样中的铁量,所得测定值与国家标准方法的测定值相符。

Based on the principle of color reaction of Fe(Ⅱ) with o-phenanthroline, a reagent tablet used specifically for rapid field analysis of water samples for iron contents was prepared and tested. Powdered reagents of sulfamic acid, o-phenanthroline, hydroxylamine hydrochloride and sodium acetate with their mass ratio of 0.2 g∶0.003 g∶0.03 g∶0.3 g respectively were mixed thoroughly and pressed into a tablet having its diameter of 10 mm and thickness of 0.3-0.4 cm under a pressure of 5 MPa with a tabletting press. When in use, one piece of the tablet was added into 10 mL of water sample, measure the absorbance of the solution at 510 nm 5 min after complete dissolution of the tablet. Standard working curve with linearity range between 0.2 to 4.0 mg·L-1 was prepared by using Fe(Ⅲ) standard solution. Detection limit (3σ) found was 0.07 mg·L-1, and value of RSD (n=6) found was 0.57% at the concentration of 1.5 mg·L-1 of Fe(Ⅲ). Three kinds of water samples were analyzed by this method, giving values of Fe-contents in consistency with those obtained by the GB standard method.