The usual determination of formaldehyde by gravimetry and spectroscopy extends down to 10−3 mg with only limited reproducibility. Radiochemical analysis using14C-labelled formaldehyde allows to determine amounts of 10−4 to 10−5 mg. This technique was, therefore, applied to detect reliably the amount of formaldehyde proportional to the activity in
viscose rayon, spun in a formaldehyde containing spinning bath by using an ionisation chamber assay. The objects investigated
were found to contain 2·10−5 mg to 1.4·10−4 mg formaldehyde, the relative error being lower than 4%. The scope of application of this method is discussed.