Flow injection analysis formaldehyde

Dong, S. and Dasgupta, P. K, Fast fluorometric flow injection analysis of formaldehyde in atmospheric water, Environ. Sci. Technol., 21(6), 581, 1987. 

The method of Fan and Dasgupta (1994) relics on tlie reaction of formaldehyde with 1,3-cyclohexane-dione in acidified ammonium acetate to form the fluorescent dihydropyridine derivative in a flow injection analysis system. Formaldehyde trapped in water can be reacted with pararosaniline and sodium sulfite under mild conditions (neutral pH, room temperature equilibration) to produce a colored product that is measured at 570 nm (Petreas et al. 1986). The presence of bisulfite is an interference in this reaction so the method cannot be used to sample atmospheres that contain sulfur dioxide. In addition, the method is reported to suffer from interferences resulting from the presence of other aldehydes and phenol (Hoogenboom et al. 1987). The indirect method of Hoogenboom et al. (1987) relies on the reaction of excess bisulfite in an aqueous solution of formaldehyde with 5,5 -dithiobis(2-nitrobenzoic acid) to form a colored product, the absorbance of which is measured at 412 nm. The method reported by Naruse et al. (1995) relies on the formation of a colored product obtained by reacting the aqueous formaldehyde with acetylacetone and ammonium acetate in acetic acid. Absorbance is measured at 414 nm. 

Methods for the collection and determination of formaldehyde in water show great similarity to those methods for air described above. The methods of Tomkins et al. (1989) and EPA (1992b) for formaldehyde in drinking water and the method of Facchini et al. (1990) for formaldehyde in fog water all rely on the formation of the DNPH derivative followed by HPLC. The method of Dong and Dasgupta (1987) relies on the reaction of formaldehyde in atmospheric water with a diketone (2,4-pentanedione) and ammonimn acetate to form a ftuorescent derivative that is measured spectrophotometrically in a flow injection analysis system. 

Automated Flow Injection Analysis System for Formaldehyde Determination... 

An automated and microprocessor-controlled flow injection analysis system was developed for formaldehyde emission measurements. This system was based on the modified pararosaniline method and a sampling rate of about 40 samples/hour was obtained. 

The need for an automated and reliable system for formaldehyde determination is now clearly recognized. In response to this need, an automated and microprocessor-controlled flow injection analysis (FIA) system was developed in our laboratory. This system is based on the use of the modified pararosaniline colorimetric method (j6). The simplicity, versatility, good precision, high sampling rate, complete automation and relatively low cost of the system make it attractive for the analysis of large numbers of formaldehyde samples. In this chapter, sufficient background in the principle of FIA will be presented to allow the readers to evaluate the technique and its potential application to the routine analysis of formaldehyde will be explored. 

FLOW INJECTION ANALYSIS WITH CHEMILUMINESCENCE DETECTION DETERMINATION OF GATIFLOXACIN USING THE KM11O4-FORMALDEHYDE SYSTEM... 

M. H. Ho, Automated Flow Injection Analysis System for Formaldehyde Determination. ACS Symp. Ser., 316 (1986) 107. 

The flow injection system described here can be used for automated analysis of large numbers of formaldehyde samples. The... 

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