Simple and green colorimetric method for the detection of formaldehyde in vegetable samples

This work presented a simple, rapid, low-cost, and green chemical approach for the quantification of formaldehyde in vegetable samples. The detection of formaldehyde depends on its oxidation with hydrogen peroxide in an alkaline medium to form formic acid, resulting in an indicator color change from blue to yellow observed by the UV-Vis spectrophotometer or even the naked eye. Under the optimal parameters, a linear calibration graph was obtained in the range of 0.001–1.5 ppm with a correlation coefficient (r2) of 0.9907. The LOD and LOQ values were 0.06 ppm and 0.22 ppm, respectively, and the repeatability expressed in terms of RSD was 4.71% (0.025 ppm formaldehyde, n = 10). The reliability of the proposed method was illustrated by spiking the formaldehyde in the vegetable samples, yielding 99.33–105.88% recoveries. The method was successfully validated using the Test-kit method. Moreover, the proposed method exhibited good selectivity towards formaldehyde over common aldehyde compounds.