Eco-Efficient Oil-in-Water Testing

ERACHECK ECO combines all benefits from well-established IR measurement techniques of oil-in-water with the ecologically safe CFC-free solvent cyclohexane. The use of a cost-efficient measurement technology in combination with the low-cost solvent cyclohexane gives you the most economical oil-in-water tester available today.

Correlation to

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Ecology meets Economy

ERACHECK ECO combines all the benefits of the known IR measurement technique such as high precision, fast and easy measurement with the ecologically safe CFC-free solvent cyclohexane. The measurement procedure requires no evaporation steps and is fully automated. Consequently no contaminants are lost that normally would evaporate together with the solvent. Using the filter-based measurement method in combination with cyclohexane gives you the most economical oil-in-water measurement system available on today’s market. And still ERACHECK ECO offers a limit of detection of 0.5 mg/L and a total measurement range up to 1 000 mg/L.

Graph that shows ERACHECK ECO's compatibility mode in comparison to ASTM D7678 measurements

Comparison with ASTM D7678

Oil-in-water concentrations usually depend on the method used to measure them. Each method measures different things such as different fractions of the oil or they use different spectral regions. This is also true for the comparison between ERACHECK ECO and ASTM D7678. They share the same spectral region, however, due to the difference in the detection system they can’t give the exact same results.

Therfore, we added a compatibility mode to ERACHECK ECO which gives results perfectly correlating with ASTM D7678. The graph on the side shows this compatibility mode for various crude oils with different API gravities, fuels and lubricants.

  • ERACHECK ECO showing the measurement menu on the screen
  • ERACHECK ECO showing a running measurement on the screen
  • ERACHECK ECO showing the measurement result on the screen

Measurement Procedure

  1. Extract the water sample with cyclohexane: Typically 900ml water are extracted with 50ml cyclohexane
  2. Select the method you want to use: TPH or TOG
  3. Select the correct calibration
  4. Enter the name of the sample and the name of the operator
  5. Press the RUN button
  6. The instrument runs a background measurement of pure cyclohexane
  7. The instrument measures your extracted sample

ERACHECK ECO guides you through the measurement procedure. The liquid volumes have to be entered depending on the actual volumes used for the extraction of the sample.

Technical Specifications

Available Test Method
Based on ASTM D7678
Correlation to
Infrared spectroscopy: ASTM D3921, D7066; DIN 38409-H18; OSPAR IR method; IP 426
Gas chromatography: ISO 9377-2, ISO 9377-2 (mod) OSPAR, ISO 16703; MADEP-EPH; EN 14039
Gravimetry: EPA 1664, EPA 9071; ASTM 4281; ISO 9377-1
TPH (Total Petroleum Hydrocarbon) and TOG (Total Oil and Grease) measurements in water and soil
Extraction Method
External liquid-liquid or solid-liquid extraction
Extraction Solvent
Sample Volume
Typically 900 mL water and 50 mL cyclohexane (min. 10 mL solvent required per measurement)
Sample Clean-up (TPH)
Simplified removal of polar substances over attachable Florisil® cartridges
Measurement Time
5 min (including background measurement)
Measurement Range
up to 1 000 mg/L oil-in-water
up to 36 000 mg/kg oil-in-soil
Limit of Detection
0.5 mg/L oil-in-water (900:50 mL H2O:Solvent)
18 mg/kg oil-in-soil (20 g:40 mL Soil:Solvent)
Enrichment factor 18 (900:50 mL H2O:Solvent)
0 – 70 mg/L ± 0.35 mg/L
70 – 400 mg/L ± 1.0 mg/L
400 – 1 000 mg/L ± 2.1 mg/L