The use of so-called ‘alternative plasticisers’ has increased over recent years due to safety concerns over conventional substances. But new methods are needed to measure human exposure to these chemicals so that their effects can be carefully monitored.
Plasticisers are added to change the physical properties of a polymeric material – providing durability, elasticity, and flexibility to products. They are most often used in plastics, especially in polyvinyl chloride (PVC).
But substantial concerns have been expressed over the safety of phthalate esters, which are the most widely used conventional plasticisers. These chemicals can be released into the environment and have been shown to cause adverse health effects in humans. As a result, the European Union (EU) recently banned the use of certain phthalates in childcare products and toys.
Over the last decade, the use of a new breed of alternative plasticisers has been increasing to replace phthalates. Among these, DPHP, DINCH, DEHTP and DEHA have been introduced for use in PVC.
Although these substances are thought to be safer – with lower toxicity and less environmental permeation – exposure to these chemicals and their metabolites could still have adverse health effects in humans. For example, laboratory studies have found that DINCH and its metabolites have cell-killing effects.
Due to the rapid growth in the use of these compounds, it is imperative that methods are developed to measure human exposure, so their effects can be carefully monitored.
Most human biomonitoring studies rely on the analysis of urine samples, due to the ease of collection. But this approach has disadvantages, such as the low concentration of target analytes and the limited time window that the sample represents.
Using hair as an alternative matrix offers some clear advantages – including improved opportunities for monitoring populations that are notoriously difficult to sample such as newborns, enabling studies to assess maternal exposure to chemicals. It can also offer a window into both the short- and long-term exposure to a substance.
A new study set out to develop and validate a liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method to analyse and quantify human exposure to DPHP, DINCH, DEHTP and DEHA in hair samples.1
After thorough optimization, the researchers found their new protocol was robust at measuring all targeted compounds except for MEHA, which they were only able to monitor qualitatively. They used ultrapure water obtained from a ELGA PURELAB® flex system to reduce the risk of introducing contaminants into these sensitive techniques.
This is the first study that tackles the measurement of alternative plasticisers and their metabolites in hair samples. This new method offers a robust way of detecting some of these substances, supporting the use of hair as an alternative matrix in human biomonitoring studies.
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Yin, S. et al. Hair as an alternative matrix to monitor human exposure to plasticizers – Development of a liquid chromatography – tandem mass spectrometry method. Journal of Chromatography B (2018): https://doi.org/10.1016/j.jchromb.2018.09.031