单扫描极谱法测定居室内空气中甲醛

Measuring Formaldehyde in Air Inside Living Quarters by Single-sweep Polarography

目的探索用单扫描极谱法测定居室内空气中的甲醛浓度。方法在0.07mol/L盐酸苯肼溶液—0.2mol/LNaCl溶液体系中,甲醛在-700mV处出现灵敏而清晰的波峰。于JP-303极谱分析仪上测定,原点点位-350mV,终止点位-1000mV,三电极,二次导数,在-700mv处读其二次导数波峰。根据峰电流与相应甲醛含量绘制标准曲线,再根据样品峰电流大小,计算样品中甲醛含量。结果其峰高与甲醛的含量成正比。在0.4ml盐酸苯肼、1.0ml氯化钠底液条件下,本方法检出范围为0.02～12.0μg/10ml,在15min～4h内峰电流稳定不变。本法与GB/T18204.25-2000相比较,相对标准偏差<3.5%,回收率为94%～102%。结论本法具有简便、快速、易操作、精密度好、灵敏度高等优点。

Objective To introduce the method to measure the content of formaldehyde in air inside the living quarters by single-sweep polarography. Methods In system with phenyl hydrazine hydrochloride 0. 07 mol/ L and NaCl 0. 2 mol/L, the formaldehyde would reveal sensitive and clear wave crest at-700 inV. JP-303 polarograph, with electric potential from original-350 mV to terminate-1 000 mV, three electrodes and quadric differential coefficient used. In measurement, the wave crests of quadric differential coefficient at the places of -700 millivohs is read, and the normal curve according to apex electric current with correspond content of the formaldehyde is drawn, then the content of formaldehyde in the sample is calculated based on the size of apex electric current. Results The kurtosis becomes the direct proportion with the content of the formalde- hyde. Checking out-range of this method is from 0. 021 to 2.0 μg/10 ml. Compared with GB/T18204. 25- 2000, the standard deviation is less than 3.5%. Conclusion The advantage of this method is simple, fast, easy operation, good sophistication, high intelligent degree etc.