This analysis is now run using Headspace (HS) Extraction and Gas Chromatography (GC) High Efficiency Source (HES) Mass Spectroscopy (MS).
The Scientific Services VOC team at our Howdon laboratory have been working on developing a new method for our THM and solvent analysis of drinking water samples. The old instrument had been in use for 10 years and used a less robust purge and trap technique that had been used for 20+ years.
The new technique uses an aliquot of the water sample which is heated and agitated in a sealed vial encouraging the volatile analytes to rise out of solution and into the vial headspace. A known volume of this gas headspace from within the vial is then injected onto a GC capillary column.
The volatile compounds which are present in the sample are separated following a specific temperature profile within the GC system and detected and quantified using a single quadrupole mass spectrometer with a High Efficiency Source (HES).
The HES allows the detection of low-level concentrations of compounds which easily meets the requirements of the Drinking Water Inspectorate (DWI). This will help future proof our analysis of potable water, should the prescribed concentration values (PCV) be reduced by the DWI.
Throughout the development and validation process we have also managed to implement an efficiency without compromising the quality of results by means of reducing the analysis run time from 20 minutes per sample, to 12 minutes per sample. This has not only allowed us the ability to analyse more samples in a shorter period, but also helps to aid with prioritising incident / urgent analysis.
The team have also worked hard to develop the method so that Vinyl Chloride has been introduced into the solvent suite. The analysis of this extremely volatile compound, as well as the THM and solvent suite, has now been granted UKAS accreditation for potable water, groundwater and surface water through our flexible scope of accreditation system.
If you would like any information regarding this or any other of the analytical or sampling services that our laboratory can provide.
Please contact our dedicated Customer Team and we will be happy to help.