The New Methods For Determination Of Formaldehyde In Environmental Samples

Chapter 1In order to establish new methods for the determination of trace formaldehyde in environmental water by kinetic spectrophotometry method , a new reaction system of HCHO-KBrO₃-AO-H₂SO₄ was selected. The properties of the absorption spectrum of the system were studied. The affecting factors on the strength of absorption including acidity, dosage, temperature, reaction time, coexisting ions and so on, and the optimal conditions of the reactions in the system were investigated. A new method based on the linear relationship of the absorbency (ΔA = A₀ - A ) to the concentration of formaldehyde in solution was established .The results showed that there was the catalytic effect of formaldehyde on the oxidation reaction of acridine orange with potassium bromate in sulphuric acid medium. The relationship of the reduced absorbency to the concentration of formaldehyde was good linearity and the maximum absorption peak located at 490nm. Based on these, a new catalytic kinetic spectrophotometric method for the determination of formaldehyde was developed. The detection limit was 1.50×10²Î¼g/ml and the linearity range were 0.0250⁰.200μg/ml for formaldehyde. The method was applied to the determination of trace formaldehyde of water samples in environment, with satisfactory results.The RSD was 1.23%².18% , the recovery rate was 93.4%¹03.5% .Chapter 2In order to establish new methods for the determination of trace formaldehyde...