Irene Tan*, Chia Poh Ling, Lim Chin Chin, Michael Tay Ming Kiong
International Forensic Science Symposium, Taipei, Taiwan.
November 2005, Research Project Paper FY05/11 (poster presentation)
Purpose of research
Detergents and household cleaning products in powder and liquid forms are sometimes encountered as anthrax hoax simulants or adulterants in soups and drinks. Cleaning products include a wide variety of laundry detergents, fabric softeners, dishwashing liquids, handwash liquids and household cleansers. The current method for the detection of detergents involves the class identification of anionic, cationic and/or non-ionic surfactants using chemical tests.
Cleaning products are seldom single chemical entities. Generally, they are mixtures containing tens to even hundreds of active components, especially for higher ethoxylated non-ionic formulations. Manufacturers often add fragrances to the formulations of cleaning products to give the consumer a feeling of well-being and freshness, and to mask undesirable odors of other chemical ingredients in a product. Fragrances are usually complex mixtures containing organic compounds such as alcohols, esters, terpenes, diterpenes, sesquiterpenoids, etc. The aim of this project is to evaluate the usefulness of profiling fragrance constituents in cleaning products as well as in water extracts containing cleaning products, in order to determine subclass characteristics and link questioned samples to a particular suspected brand or formulation of cleaning products.
The most common technique for analyzing fragrances is gas chromatography coupled with mass spectrometry (GC/MS). GC/MS is the method of choice for the efficient separation and identification of trace amounts of volatile organic compounds found in fragrance blends and other additives.
Problems to be solved
Fragrance compounds encompass a variety of organic components such as aldehydes, terpenes, alcohols and esters. These compounds exhibit significant variations in molecular size, polarity and chemical interactions. Since cleaning products are often encountered in the adulteration of food and drinks, an efficient extraction technique for the fragrance components of cleaning products from complex food matrices needs to be developed. In this project, we evaluated solvents of different polarities for the extraction of fragrance components used in cleaning products. In addition, the use of passive carbon strip absorption followed by solvent elution was studied and compared to the direct liquid extraction technique. The detection limits of these fragrance components in water extracts containing cleaning products were also studied.
Thirteen common household cleaning products were studied. Five different solvents, namely carbon disulfide, dichloromethane, diethyl ether, ethyl acetate and methanol were used for the extraction of organic components from small quantities of powder and liquid cleaning products. Static headspace adsorption was performed using activated carbon strips. A Shimadzu GC-17A gas chromatograph fitted with a DB-5ms (30m ¥ 0.25mm ¥ 0.25mm) column and coupled to a QP5050A quadrupole mass spectrometer was used for analysis of the extracts.
Results and Discussions
Preliminary studies showed that dichloromethane was the best solvent for the extraction of fragrance components from cleaning products. Laundry detergents of the same brand but different formulations (granular and liquid forms) were found to have different chromatographic profiles. In addition, all the cleaning products studied were found to be different in composition and/or chromatographic profile. The advantages and limitation of passive headspace carbon strip adsorption technique compared to liquid-liquid extraction would be further discussed in the paper. The detection limit of these fragrant components in water extracts containing cleaning products would also be further discussed in the paper.
The extraction and GC/MS identification of fragrance compounds in cleaning products is a powerful technique for discriminating different cleaning products and formulations. The method is sensitive and allows trace amounts of characteristic fragrance compounds to be recovered from food and drinks matrices, and subsequently identified and linked to specific cleaning products or formulations.