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B. Lendl, W. Ritter:
"Progress report on the new mid-IR laser based analyzer for total petroleum hydrocarbons in water";
Hauptvortrag: Oil in Water Monitoring Workshop 2009, Abderdeen; 15.09.2008.

The Eracheck uses a mid-IR quantum cascade laser for measuring hydrocarbons in water. The sample preparation process consists of a liquid-liquid extraction using a cyclic, aliphatic hydrocarbon such as cyclohexane or cyclopentane. The liquid extract is dried with sodium sulfate and polar compounds are removed by filtration over Silicagel. The quantification step consists of measurement of a blank of the extraction solvent used and measurement of the extract itself.
The new IR method shows a linear response from 0.5 to 1000 ppm of hydrocarbons in water with r.s.d of less than 3 % at 10 ppm.
This presentation reports on the recent results obtained with this new IR based analyzer and compares them to the results obtained using the GC method ISO 9377-2 as well as the old DIN 38049-H18 method which used Freon 113 as the extraction solvent. Results are discussed in terms of recovery, precision and practicability for at-line measurements at a water treatment plant of OMV in Austria. In this particular application the portable Eracheck showed to be capable to accurately determine the hydrocarbon concentration at three different sampling points with typical hydrocarbon concentration ranging from 5-10 mg/L, 50-150 mg/L and 150-300 mg/L respectively. Finally, an update on our efforts to establish an ASTM method based on the principle of the IR method is given as well.