静态抑制荧光法和流动注射抑制荧光法测定微量甲醛的研究

利用甲醛在中性或弱酸性条件下对亚硫酸盐邻苯二甲醛铵盐体系具有抑制作用,建立了测定甲醛的静态抑制荧光法和流动注射抑制荧光法。研究了测定甲醛的最佳条件。在最佳条件下,静态抑制荧光法测定甲醛的线性范围为010～160μg·mL-1,检测限为0046μg·mL-1;流动注射抑制荧光法测定甲醛的线性范围为010～200μg·mL-1,检测限为0085μg·mL-1。用于河水中甲醛测定,与乙酰丙酮分光光度法(GB13197—91)比较,误差分别为083%和125%。

Study of Direct Fluorophotometric and Flow-Injection Fluorophotometric Methods Based on the Inhibitory Effect for the Determination of Trace Formaldehyde

Sulfite reacts with o-phthalaldehyde in the presence of ammonium forming the highly fluorescing isoindole-1-sulfonate in neutral or weakly acid solution, and formaldehyde has inhibitory effect on it. Based on this principle, the authors developed the direct fluorophotometric and flow-injection fluorophotometric methods for the determination of trace formaldehyde. The maximum excitation wavelength and the maximum emission wavelength are 320 and 390 nm respectively. With the direct fluorophotometric method, formaldehyde in the concentration range of 0.10-1.60 microg x mL(-1) can be determined with a detection limit of 0.046 microg x mL(-1). With the flow-injection fluorophotometric method, formaldehyde in the concentration range of 0.10-2.00 microg x mL(-1) can be determined with a detection limit of 0.085 microg x mL(-1). The methods were applied respectively to the analysis of river water with satisfactory results.