Quantitative & Qualitative Determination of Dimethyl Phthalate and N, N'-Diethyl-M-Toluamide in Repellents Commercial Formulations by High Performance Thin Layer Chromatography (HPTLC)

The high performance thin layer chromatography (HPTLC) is an inexpensive, fast and easy method in comparison with other material analysis methods. Gas chromatography (GC) method usually is used to analysis repellents. In this study HPTLC is used to simultaneous quantitative and qualitative determination of diethyl meta-toluamide (DEET) and dimethyl phthalate (DMP), which are the main elements and active ingredients in current chemical repellents. Some defined amounts of commercial form of 3 repellents included trench pomade, Stick Insect Repellent (SIR), which is containing 33% of DEET and DMP60 (dimethyl phthalate 60%) which were dissolved in ethyl acetate solvent, separately. The method employed TLC aluminum plate precoated with silica gel plates (SiO4) 60F245 as the stationary phase. The solvent system consisted of benzene-diethyl ether-hexane (5:3:2, v/v/v) as mobile phase. The multiple level methods used for spotting. Densitometric analysis of repellents was carried out with used of TLC scanner 3 and CATS Software in the absorption / reflection mode at 230 nm. According to the results, the type and amount of active ingredients in DMP60 lotion is 61.8 g (SE=±1.6) per 100 cc of dimethyl phthalate and in SIR, 31.3g (SE= ±0.8) of diethyl meta-toluamide per 100 g. Also the active ingredients in trench pomade were determined as a combination of DMP and DEET by rates of 5.5g (SE= ±0.2) and 25g (SE= ±1) per 100 cc of the repellent, respectively. In this study, the value of Rf for DMP and DEET was calculated 0.71±0.02 and 0.32±0.02, respectively. HPTLC is a suitable method to quantitatively and quantitatively determine repellents which have DMP and DEET active ingredients. Since most of commercial chemical repellents have this active ingredient, Adjusting and setting HPTLC up can be important.