Digital camera analysis of dichlorvos by phloroglucinol and quantitate with standard colour chart in environmental water matrices – an approach

Abstract

Dichlorvos (DDVP) analysis using visible spectrophotometer, gas chromatography mass spectrometry and liquid chromatography mass spectrometry was studied extensively. The major drawback of all the method is requirement of standardisation, expensive and maintenance nature of instrument involvement. Since, many government has banned the use of DDVP, standardisation is quite challenging with single point standard method. In this study, using digital camera based colour analysis for DDVP was carried out to develop one-time multi standard colour chart. The analysis was carried out by alkaline degradation of DDVP to dichloro acetylaldehyde to react with phloroglucinol and producing distinct colour gradients from pale purple to dark brown. The colour chart was able to quantitate the limit of detection and limit of quantification of 6 µg/mL and 20 µg/mL respectively. The study was further experimented with real-time ground water with non-spiked and spiked DDVP samples for pre-concentration effect. The 1:1 linear relation was found with absorbance based spectrophotometer detection and digital camera image analysis to quantify around ppb level. This shows the colour analysis by human eye judgement is possible at certain level as semi-quantitate by strategical approach. In this paper, we have used the colour chart based digital camera detection of DDVP, which will be a viable alternate approach for analysing the environment samples.