测定水溶性酚醛树脂胶粘剂中游离甲醛含量方法的改进

Improved Analytical Method for Free Formaldehyde in Adhesive of Water-Soluble Phenol-Formaldehyde Resin

改进了乙酰丙酮分光光度法测定水溶性酚醛树脂胶粘剂中游离甲醛含量的方法。研究了方法的影响因素,确定了测定条件。本方法采用添加乙酸-乙酸铵缓冲溶液后,过滤来制备试样液。排除了树脂和样品颜色的干扰。与传统的蒸馏法相比,回收率高,操作方便。回收率可达97.7%～99.3%。而蒸馏法的回收率是91.1%。方法的相对标准偏差小于2.1%。研究发现含缓冲溶液的标准溶液和试样液,在室温下稳定。不必现配现用或储存在冰箱中。2 000倍苯酚对甲醛测定不产生干扰。与化学滴定法相比,检测限低,试剂用量少。在测定低含量的甲醛时准确度高。适合于水溶性酚醛树脂中游离甲醛含量的测定。

An improved analytical method(acetylacetone spectrophotometry) for the determination of free formaldehyde in adhesive of water-soluble phenol-formaldehyde resin was established.The influencing factors were studied and the testing conditions were determined.The sample solutions used in this method were prepared by adding buffer solution of acetic acid-ammonium acetate and filtrating.The interferences from resin and sample color were eliminated.Good recoveries from 97.7% to 99.3% were obtained.They were higher than the ones obtained by traditional straight-run distillation process,which were 91.1%.The relative standard deviations obtained by this method were lower than 2.1%.This research discovered that the sample solution and the formaldehyde standard solution were stable when the buffer solution was added.The formaldehyde determination with this analytical method wasn′t disturbed by the phenol when its concentration was 2 000 times as high as the formaldehyde.Compared with chemical titrimetric methods,this analytical method has many advantages such as low detection limit,reagent and sample usages in small amount,high accuracy when the formaldehyde content in the sample is low.It was suitable for the determination of free formaldehyde in water-soluble phenol-formaldehyde resin.