方法采用品红亚硫酸法和乙酰丙酮法测定吊白块中甲醛含量，并计算样品中吊白块的含量。

Methods The content of formaldehyde in rongalite was determined by sulfurous acid, magenta and acetylacetone spectrophotometry respectively.

前言：目的：对食品中的吊白块进行检测。

Objective: To test sodium formaldehyde sulfoxylate in food.

目的：探讨食品中甲醛和吊白块的测定方法。

Objective: to explore the mensuration of formaldehyde and sodium formaldehyde sulfoxylate for food.

制作过程中加入吊白块，用酸碱滴定法分别测定水豆腐压滤液、离浆液和蒸馏液中甲醛含量。

The formaldehyde contents in tofu filtrate, liquid separated from beancurd and the distillate of beancurd were measured by acid-base titration.