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Chemical Technology • October 2015
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Organic fingerprinting
using Gas Chromatography-Mass Spectrometry
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;
• Polychlorinated Biphenyls (PCBs);
• Organochlorine Pesticides (OCPs);
• Organophosphorous Pesticides (OPPs);
• 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
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.