In view of the fact that a large amount of formaldehyde was involved in the production of urea–formaldehyde fertilizer, and the residual and decomposed formaldehyde has never been paid attention to. In this paper, the determination method of free formaldehyde content in urea–formaldehyde fertilizer was studied. A simple and accurate method for the determination of formaldehyde in urea–formaldehyde fertilizer was established based on the screening of traditional iodometry titration and acetylacetone colorimetry. The recovery rate of titration method and colorimetric method were 73.9–94.5% and 96.5–103.9%, which indicated that colorimetric method was more accurate. The optimized test conditions are as follows: fertilizer/water extraction ratio 1/20, developer acetylacetone 6 mL, the condition of reacting at 60 °C for 30 min. The linear range of formaldehyde content in urea–formaldehyde fertilizer determined by optimized method is 0.21–3.26 g/mL.

鉴于尿素-甲醛肥料的生产中涉及大量甲醛，因此从未关注残留和分解的甲醛。本文研究了尿素-甲醛肥料中游离甲醛含量的测定方法。在筛选传统的碘量滴定法和乙酰丙酮比色法的基础上，建立了一种简便，准确的尿素甲醛肥料中甲醛测定方法。滴定法和比色法的回收率分别为73.9–94.5％和96.5–103.9％，表明比色法更为准确。优化的测试条件如下：肥料/水的萃取比为1/20，显影剂乙酰丙酮为6 mL，在60°C下反应30分钟的条件。