抗坏血酸还原-钼蓝分光光度法测定环境空气中五氧化二磷

Determination of phosphorus pentoxide in ambient air by molybdenum blue ascorbiaccid to deoxidize spectrophotometric method

建立了氯乙烯滤膜采样,抗坏血酸还原-钼蓝分光光度法测定环境空气中五氧化二磷的方法,确定了测定最佳波长和比色皿规格,比较了反应体系不同的酸度,钼酸铵、抗坏血酸及酒石酸锑钾的试剂用量,显色温度和时间等对方法的影响,同时分别对氯乙烯滤膜、玻璃纤维滤膜和石英滤膜进行了对比,发现氯乙烯滤膜具有较低的本底空白;经条件优化后,标准曲线相关系数为0.9999,当采样体积为5 m3时,方法的检出限和测定下限分别为0.15μg/m3和0.60μg/m3,高低两种浓度的空白滤膜和实际样品加标,方法的精密度均在10%以内,加标回收率在97%～110%之间。分别研究了As,Hg,Cr,Si和氟化物等对方法的干扰和消除,当As含量大于0.2μg/m3,Cr（Ⅵ）含量大于200μg/m3时对方法负干扰,Na SO3溶液和Na2S2O3溶液的混合还原剂可以消除,使用混合还原剂先配制再加入的方法可以在一定程度上消除含硅化合物的正干扰,Hg和氟化物对方法不产生干扰。

Determination of phosphorus pentoxide in ambient air by molybdenum blue ascorbiaccid to deoxidize spectrophotometric method has been established. In order to acquire the optimal conditions,various parameters were studied,such as wavelength,cuvette specifications,different acidities of reaction system,the amount of the reagent ammonium molybdate,ascorbic acid and potassium antimony tartrate,color temperature and time. At the same time, three different filters vinyl chloridefilter, glass fiber filter and quartz filter were compared respectively,and it was found that vinyl chloride filter has low background. Results show that this method has a good performance,a wide range of the standard curve,the linear correlation coefficient of 0. 9999,the detection limit and low determination limit are 0. 15 and 0. 60 μg / m3,respectively when the sampling volume is 5 m3; In addition the recoveries of different concentrations in blank quartz filters and actual samples are in the range of97%- 110%,precision is less than 10%. Combined with practical work, effects of arsenic, mercury,chromium,silicon and fluoride on the method were studied. When the arsenic content is more than 0. 2 μg / m3 and chromium（ VI） content is more than 200 μg / m3,negative interference on this method is found,the mixed solution of sodium sulfite and sodium thiosulfate could eliminate the interference. The interference of silicon can be eliminated by first preparation of the mixed reductants and then added,and mercury and fluoride does not generate interference on this method.