Introducing a Colorimetric Method for the Detection of Methanol in Several Types of Drinks

Background and The presence of methanol in different types of drinks has caused problems and concerns. Therefore, developing a simple qualitative method to detect methanol in these products seems necessary. Ïn this study, a new easy low-risk sensitive and accurate method based on chromotropic acid (ÇÂ) has been suggested for the qualitative detection of methanol in various types of drinks. This study was conducted based on the conversion of methanol to formaldehyde to make a specific purple complex between formaldehyde and Çhromotropic acid in an extremely hot and acidic environment. Ïn this study two series of solutions with concentrations of 1, 5, 10, 20, 30, 40, 50 mg/L of methanol in distilled water and 10, 50, 100, 200, 400, 500, 1000 mg/L of methanol in ethanol 60º were prepared to determine the detection limit of the suggested method. The result of the test was positive and a change into purple was observed in the concentrations of more than 10 mg/L in aqueous solution, and 500 mg/L in ethanol 60º, respectively. Therefore, the detection limit of this method was determined to be 10 mg/L for the detection of methanol in the solutions without ethanol and 500 mg/L in ethanol 60º solutions. Âpplication of small and calculated amounts of reactants in low aqueous medium led to the elimination of heat.Çonclusion: The suggested method can qualitatively detect methanol in different type of drinks easily and with no need for especial laboratory equipments and high technical knowledge in a short time. Therefore, it can be used as a semi-control method for the qualitative detection of methanol in various types of drinks.