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

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.