The Stabilization of Small Concentrations of Formaldehyde in A queous Solutions

Abstract

Based on the Hantzsch-reaction, a stabilization (fixation) of small concentrations of formaldehyde in aqueous solutions (<0.4vq CH20/ml) can be performed, allowing a storaqe of these solutions for 1 week in darkness. (Aex = 410 nm, Xem = 510 nm), formed as a result of the Hantzsch-reaction, CH20-concentrations down to 0.02 vq/ml can be determined fluorimetrically up to 7 days after preparation (sampling). at room temperature, Usinq the fluorescent nature of 3,5-diacetyl-l,4-dihydrolutidine In the determination of formaldehyde according to the Hantzsch-reaction, other aldehydes, amines and ketocompounds, at the same time present in the air, may cause interference.1073

Fogwater chemistry in an urban atmosphere

“…In the field, samples were stored over ice, then refrigerated when brought back to the laboratory; pH was determined in the field with a Radiometer PHM 80 meter. Sulfite was preserved by addition of CH 20 at pH 4 to form hydroxymethanesulfonic acid (HMSA) [Dasgupta et al, 1980;Fortune and Dellinger, 1982]' 3,5-diacetyl-l,4-dihydrolutidine (DDL) formed by reaction of formaldehyde and acetyl acetone in the presence of NH4 + [Nash, 1953] is stable for at least 7 days [Rietz, 1980]. Sulfite is known to interfere with this reaction [Nash, 1953], but no correction was made.…”

The occurrence of bisulfite-aldehyde addition products in fog- and cloudwater

“…Aliquots were removed from the samples immediately after collection and preserved. Formaldehyde was preserved as 3,5-diacetyt-l,4-dihydrolutidine (DDL) (Nash, 1953;Reitz, 1980). The absorbance of the DDL was measured at 412 nm on a Beckman Acta III spectrometer.…”

Effects of Climatic Parameters on Formaldehyde Concentrations in Indoor Air

“…The substance is known to be an ubiquitously occurring chemical pollutant and is now the most abundant carbonyl compound in our atmospheric environment (Roffael, 1993;Walker, 1964;Finlayson-Pins and Pitts, 1986). It is widely used as a basic material for a number of different applications.…”