Objective To establish a method for the detection of formaldehyde in workplace air by the automatic discrete analyzer.

Methods The discontinuous chemical analyzer was used instead of the manual method for the determination of formaldehyde. The detection steps and test working conditions were determined; the linear range, detection limit, accuracy, precision, and other indicators of the method were observed and compared with the GBZ/T 300.99-2017 method.

Results There was a linear relationship between formaldehyde concentration ranging from 0 to 0.4 mg/L and absorbance, with a correlation coefficient of 0.999 9. The detection limit was 0.000 9 mg/L, and the minimum detection concentration was 0.001 5 mg/m³(calculated by collecting 3 L of air sample). The intra-assay precision was 2.39%-4.75%, and the inter-assay precision was 2.91%-9.30%. The results of the standard samples were within the calibration range. When this method was used for the determination of formaldehyde in the air of the workplaces, the relative error between the measured value and the value derived by the national standard method was within 10%, and the two groups of results had a good linear correlation(r=0.998, P < 0.001).

Conclusions The automatic discrete analyzer had a high degree of automation, sensitivity, linear relationship, precision, and accuracy in determining formaldehyde in the air of the workplaces. It can replace the manual method and is suitable for efficient detection of formaldehyde in the air of the workplaces.