We compared results by a simplified colorimetric copper-soap method for serum free fatty acids (Clin, Chem. 19: 419, 1973, modified) with those by a gas--liquid chromatographic method. The modified method requires only 100 microliters of sample, its standard curve is linear from 0.1 to 4.0 mmol/L (reference interval for adults: 0.2 to 0.8 mmol/L), and it is suitable for use with newborns. Compa...

A comparison of methods, two based upon 5-hydroxymethylfurfural determination (colorimetric using a semi-automated procedure and HPLC) and ion exchange chromatography (HbA1 using BioRad method) was performed. The influence of variables on 5-hydroxymethylfurfural determination is reported. The dialysis step appears to be essential for an accurate determination of 5-hydroxymethylfurfural released...

BACKGROUND Despite a significant increase in the number of patients with paracetamol poisoning in the developing world, plasma paracetamol assays are not widely available. The purpose of this study was to assess a low-cost modified colorimetric paracetamol assay that has the potential to be performed in small laboratories with restricted resources. METHODS The paracetamol assay used in this s...

In 1963 Umberger and Fiorese (1) introduced a colorimetric method for HA,1 based on the color reaction of HA, dissolved in anhydrous pyridine, with BSC. Therefore, for applying their method to determine HA in urine, HA must first be extracted from the urine. We found that HA dissolved in water-pyridine (1:1, by vol) produces a red-orange color when BSC is added at room temperature. The absorpti...

The covalent immobilization of synthetic or natural macromolecular compounds containing amino groups onto polystyrene (PS) solid surfaces is of great interest in diagnostic applications. A sensitive assay allowing the determination of reactive end groups is therefore a powerful tool for predicting the performance of the active surface. Recently, we reported the use of the Coomassie brilliant bl...