Method Statement Toluene Extractable Matter/Free
Sulphur
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Contents
Introduction
Principle
Performance
Characteristics
Range
of Application
Limit of
Detection
Analytical
Quality Control
References
Introduction
The performance of this method is validated in accordance with
internationally recognised procedures.
This procedure describes the determination of toluene extractable
matter (tolex) and free sulphur in soils and waters by solvent
extraction and gravimetric determination.
Principle
An aliquot of the test sample is extracted with hot toluene. The
extracted residue is determined gravimetrically. If free sulphur is
required, the extract is attacked with concentrated sulphuric acid.
The residue is then re-extracted, filtered and weighed to determine
free sulphur content.
Performance
Characteristics
Substances Determined
Toluene extractable material and free sulphur in soils and water.
Range of Application
Limit of Detection
Analytical Quality
Control
Analytical quality control is maintained by a number of measures:
Multi-point calibration with
authentic standards (with defined minimum performance
characteristics)
Analysis of control samples within
each analytical batch, such as independent standards, matrix spikes
or reference materials
Analysis of reagent/method blanks
within each analytical batch
Ongoing quality assured by the use
of control charts in conjunction with warning and action limits for
the QC sample data
Participation in external
proficiency testing and interlaboratory schemes such as LGC CONTEST,
HSE WASP, CSL FAPAS
References
Standard Methods for the
Examination of Waters and Wastewaters. 18th Edition 1992.
APHA-AWWA-WEF.
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