Alternative method for determining formaldehyde in commercial samples
A spectrophotometric method using magnesium sulphate instead of concentrated sulphuric acid is proposed for the analysis of formaldehyde in disinfectants and hair products.
Magnesium sulphate heptahydrate is not included in the database for substances known to be of concern, according to SUBSPORT criteria. It is not classified according to EU harmonized legislation and is not self-classified in ECHA C&L Inventory database. The MSDS of one of the distributors identified possible irritation to skin, eye and respiratory tract due to exposure to magnesium sulphate heptahydrate (see Further information).
An alternative method for the analysis of formaldehyde in commercial products replaces concentrated sulphuric acid by magnesium sulphate.The method was applied in a laboratory study for the analysis of commercial disinfectants and deffrizzing hair products containing illicit formaldehyde.
Both the original and the alternative spectrophotometric methods are based on the reaction of formaldehyde with chromotropic acid. The original method (published by NIOSH 1994, method 3500(2) ) uses concentrated sulphuric acid heated on a steam bath (1000C) for about one hour. The alternative also includes the heating stage on the steam bath but uses a 60% magnesium sulphate (heptahydrate) aqueous solution instead of the corrosive sulphuric acid.
The alternative method proved to have good selectivity for formaldehyde and high accuracy.
The alternative is easy to implement. It reduces the chemical risks associated with the use of sulphuric acid, classified as corrosive. Magnesium sulphate is not classified corrosive ( it is however an irritant) and being a coarse powder it is easier to transport, store and manipulate compared liquid, concentrated sulphuric acid.
– Magnesium sulphate heptahydrate MSDS for Sigma Aldrich
– National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods (NMAN), 4th ed., US Department of Health, Education and Welfare: US, 1994, method 3500(2) – formaldehyde.Further languages available
Type of information supplier
Fabrícia Gasparini, Patrícia L. Weinert, Liliane S. Lima, Leonardo Pezza and Helena R. Pezza
Instituto de Química, Universidade Estadual Paulista, CP 355, 14801-970 Araraquara-SP, Brazil
J. Braz. Chem. Soc., Vol. 19, No. 8, 1531-1537, 2008.,
The information is based on the article ’ A Simple and Green Analytical Method for the Determination of Formaldehyde’ writen by Fabrícia Gasparini, Patrícia L. Weinert, Liliane S. Lima, Leonardo Pezza and Helena R. Pezza and published in J. Braz. Chem. Soc., Vol. 19, No. 8, 1531-1537, 2008.Type of publication and availability
Article published in scientific journal, freely available
Original document: click here
Publication or last update: September 2011