Chemical Technology October 2015

Organic fingerprinting using Gas Chromatography-Mass Spectrometry

Editor of ‘Chemical Technology’, Glynnis Koch, recently paid a visit to ERWAT Laboratory Services, a SANAS 17025 accredited laboratory, to talk to Denver Karshagen, GC-MS chemist in charge of the specialist laboratory for organic water and soil analysis.

E RWAT offers the water industry a wide variety of services in the fields of chemical and microbiological analyses, as well as expert advice on water-related problems. It considers its business to be the management of the earth’s most sensitive natural resource: water. As a re- sult, the company is committed to the protection of the envi- ronment by avoiding pollution of natural streams, groundwa- ter, soil and air. Purified effluent is managed to ensure envi- ronmentally safe water is discharged to rivers and streams. ERWAT Laboratory Services offers advanced chemical and bacteriological laboratory analyses. It aims to serve cli- ents and the environment and support clients in wastewater investigations; to analyse low to high-range concentrations on samples and to handle large volumes, as well as to offer affordable scientific services in a short turnaround time. Services offered also include: evaluation of effluent processes, dams, lakes and river systems; wastewater and potable water treatment; industrial processes and effluent monitoring programmes; product loss control and effluent quality surveys; pollution risk surveys and wastewater efflu- ent plant operation, troubleshooting and problem solving. Denver Karshagen began working at the ERWAT Labora- tories situated in Hartebeestfontein Office Park in Kempton Park, Gauteng, over seven years ago, when he was employed to start up a specialist laboratory for organic water and soil analyses, mainly in the area of environmental testing. Specifi- cally, the laboratory carries out Gas Chromatography-Mass- Spectrometry (GC-MS) applications on a variety of liquid and solid samplematrices whichmay come from the local council, industry, water treatment works, or even private clients. GC-MS is very much the tool of choice for tracking organic

pollutants in the environment, according to Denver. Although there are some compounds for which the technique is not suitable, for most organic analysis of environmental samples, including many major classes of pesticides, it is extremely sensitive and effective. At the ERWAT Laboratory, GC-MS analysis of organic determinants, based on EPA method specifications, cover the following: • Volatile organic compounds (VOCs) including Ben- zene Toluene Ethylbenzene Xylenes and Naphthalene (BTEXN) components; • Semi-volatile organic compounds (SVOCs) including Polycyclic aromatic hydrocarbons (PAHs) and Phenols; • Total Petroleum Hydrocarbons (TPH-GC) including Gaso- line Range Organics (GROs and Diesel Range Organics (DROs); and • Organic fingerprinting (GC-MS scans). Denver pointed out that organic fingerprinting is one of the most interesting applications of GC-MS. The scans that result from the analysis may be described as a forensic type of application, in the sense that tracing back problem samples, such as from a pollution incident, (for example, the discharging of effluents from chemical plants into a river or a dam), is made possible. The object of testing samples is to find out their source by being able to identify the organic compounds within the samples. Reference samples are taken from sites suspected of causing the pollution. Using organic profiling, these • Polychlorinated Biphenyls (PCBs); • Organochlorine Pesticides (OCPs); • Organophosphorous Pesticides (OPPs);

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Chemical Technology • October 2015