o-Cresol, p-Cresol and Phenol in Urine - HPLC

Order No.: 41000, for 100 tests
o-Cresol, p-Cresol, Phenol

Easy sample preparation
Efficient acid hydrolysis
With custom-made internal standard

CE-IVD validated product ready for IVDR within timeframes and transition periods specified by the IVDR-2022 regulation




Clinical relevance

Cresol and phenol are formed as metabolites in the body after exposure to toluene and benzene respectively. Toluene and benzene are toxic substances which are used on an industrial scale e.g. as solvents and fuel additives. Determination of the metabolite concentration in people exposed at work is performed as a measure for the occupational health monitoring of toluene and benzene exposure at work.

For any hazardous substance or its metabolite, a BTV (Biological Tolerance Value) is defined as a threshold value for maximum exposure, which assures safe working conditions without detriment to the health of the employee. If insufficient toxicological data is available to define a BTV, the so-called Biological Guideline Value (BGV) is suggested. With carcinogenic substances, generally no BTVs are defined, and the BGV should be used instead.


Product advantages

  • Easy sample preparation
  • Efficient acid hydrolysis
  • With tailor-made internal standard


This Chromsystems assay allows for reliable and fast chromatographic determination of ortho- and para-cresol as well as phenol in an isocratic HPLC run. Sample preparation is fast and simple and requires only two steps: The first step is the acid hydrolysis, in which the phenols present in the form of sulphate and glucuronide conjugates are transformed efficiently into the free form.

The typical problems that occur in enzymatic cleavages, such as long reaction time or incomplete release, are avoided. In the second step, the samples are stabilised by adding a special buffer. The analytes are then measured using optimised chromatographic separation with highly sensitive fluorescence detection, so that potential interferences are mostly excluded. The inclusion of a tailor-made internal standard assures high precision and reliability in quantifying the analytes.

More Information
Method of Analysis HPLC
Number of Tests 100
Limit of quantification

0.04 mg/l


Phenol: at least to 50 mg/l
o-Cresol: at least to 20 mg/l
p-Cresol: at least  to 200 mg/l

Recovery 97–98 %

CV ≤ 2.2 %

Interassay CV ≤ 3.8 %
Analysis Time 14 min
Reference ranges

Occupational tolerance limits in urine

Total phenol: 200 mg/l (BGV)
Total cresol: 200 mg/l (BGV)
o-cresol (as metabolite of toluene):

1.5 mg/l (BTV)

Reference range in urine (mg/g creatinine)

Total phenol: 4.5-20.7
p-Cresol: 5.5-65
o-Cresol: n.d.
Specimen Urine
Pre-analytic Treatment

The patient samples are stable up to 3 days at ambient temperature, at +2 to +8 °C up to 4 weeks. For longer storage (up to 2 months) keep samples below -18 °C.


Sample Preparation
  • 100 µl Urine
    150 µl Hydrolysis Reagent
    and 50 µl Internal Standard
    in a hydrolysis vial*, seal tightly and mix briefly.
  • Incubate 30 min at 95 °C.
  • Let the sample cool down (approx. 5 min at ambient temperature).
  • Add 600 µl Stabilisation Buffer, seal vial again, mix briefly.
  • Inject 10 µl into the HPLC system.

*The hydrolysis vials are suitable as sample vials for a number of commonly used autosamplers.

Sample Stability Tightly sealed in glass vials the prepared samples can be kept for 1 week at room temperature or for 2 weeks at +2 to +8 °C or below -18 °C.
Injection Volume 10 µl
Flow rate 1.3 ml/min
Column temperature 30 °C
Wavelength EX 270 nm, EM 300 nm
Additional Info Any isocratic HPLC system with fluorescence detector is suitable.

Please note The freely available information on this website, in particular on the sample preparation, are not sufficient to work with our products. Please read instructions and warning notices on products and/or instruction manuals.
Parameter o-Cresol, p-Cresol, Phenol
As a customer please login or register to gain full access.