Determination of trace amount of formaldehyde base on a bromate-Malachite Green system

•A method to determinate FA has been developed based on MG-bromate system.•The developed method was sensitive, selective and accurate.•The developed method was optimized to determinate trace amount of FA in samples.•A good repeatability and accuracy were obtained from the determination of FA in samples.

A novel catalytic kinetic spectrophotometric method for determination of trace amount of formaldehyde (FA) has been established, based on catalytic effect of trace amount of FA on the oxidation of Malachite Green (MG) by potassium bromate in presence of sulfuric acid medium, and was reported for the first time. The method was monitored by measuring the decrease in absorbance of MG at 617 nm and allowed a precise determination of FA in the range of 0.003–0.08 μg mL−1, with a limit of detection down to 1 ng mL−1. The relative standard deviation of 10 replicate measurements was 1.63%. The method developed was approved to be sensitive, selective and accurate, and adopted to determinate free FA in samples directly with good accuracy and reproducibility.

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