National Environmental Monitoring Conference

House dust contains a wide variety of compounds from both indoor and outdoor
sources, and it is widely used as a sampling medium for assessing
potential human exposures in residential environments. Phthalate esters
have been used extensively as plasticizers to improve the flexibility of
polymers and their presence in the indoor environment has been
successfully identified by chemical analysis of house dust samples. Many
phthalates have been subjected to stringent regulations due to reported
adverse biological effects. Therefore, a number of alternatives to
phthalate esters have been developed and are available on the market,
including diisononyl cyclohexane-1,2-dicarboxylate (DINCH),
di(propylheptyl) orthophthalate (DPHP ), and trioctyl trimellitate
(TOTM). However, knowledge of the occurrence of these emerging
alternative phthalates in the environment is limited.
The objective of the present study is to develop a rapid and sensitive
method for the simultaneous determination of 15 phthalate alternatives
in indoor dust samples. The analytical method was developed based on
solvent extraction by sonication, sample cleanup by solid phase
extraction (SPE), with separation and detection by gas chromatography -
tandem mass spectrometry (GC-MS/MS). The method demonstrated good
recovery and high sensitivity for all the target compounds. This new
method was applied to the analysis of 56 settled indoor dust samples
collected under the Canadian House Dust Study. Preliminary results
showed that TOTM, DPHP, and DINCH were detected with frequencies higher
than 90%, with median concentrations of 0.43 mg/g, 2.6 mg/g, and 5.9 mg/g,
respectively (n=56). The new method will be used to analyze a
nationally representative dust sample set, in order to generate
statistically robust indoor exposure data which will inform risk
assessment and management of these chemicals of emerging concern.