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本文介绍了用玻璃纤维滤膜涂上2,4-二硝基苯肼(DNP),有泵或无泵采集空气中甲醛,3.0 ml乙腈从滤膜上洗脱甲醛的衍生物,并用高压液相色谱法测定。高压液相色谱条件:使用配有紫外分光光度计的液相色谱仪,波长365 nm,C-18(10μm)柱(100×5 mmi.d.),流动相为60％乙腈水溶液,流速为0.8 ml/分,进样10 μl。有泵采样滤膜的制备:取300 mg DNP(4M HCl重结晶两次)加5 ml 10％磷酸和5 ml除甲醛的乙腈,边加热边搅拌混合液,将直径13 mm的玻璃纤维滤膜浸于热溶液内几秒钟。然后置于用饱和氯化钠溶液保持恒定相对湿度的干燥器内。以这种方式涂十张滤膜平均重量增加8.3 mg,为了避免高速采样(0.5～1升/分)时的穿透,涂层不应少于8 mg。
This article describes the use of glass fiber membrane coated with 2,4-dinitrophenylhydrazine (DNP), with or without a pump to collect formaldehyde in the air, 3.0 ml of acetonitrile to elute formaldehyde from the filter derivatives, and high pressure liquid Determination by phase chromatography. High-pressure liquid chromatography conditions: A liquid chromatograph equipped with an ultraviolet spectrophotometer was used. The mobile phase was a 60% aqueous solution of acetonitrile at a wavelength of 365 nm and a C-18 (10 μm) column 0.8 ml / min, injection 10 μl. Preparation of pump sampling filter: Take 300 mg of DNP (4M HCl recrystallization twice) plus 5 ml of 10% phosphoric acid and 5 ml of formaldehyde in addition to acetonitrile, while heating the mixture was stirred, the diameter of 13 mm glass fiber membrane Dip in hot solution for a few seconds. Then placed in a desiccator maintained at a constant relative humidity with saturated sodium chloride solution. The average weight of the ten membranes coated in this manner increased by 8.3 mg and the coating should not be less than 8 mg in order to avoid penetration at high sampling rates (0.5-1 liter / min).