METHOD FOR DETERMINATION OF 3-METHOXYHYDROXY BENZENE IN BIOLOGICAL MATERIAL Russian patent published in 2017 - IPC G01N33/50 G01N30/02 G01N30/72 

FIELD: chemistry.

SUBSTANCE: invention refers to toxicology, namely, to a method for determination of 3-methoxyhydroxy benzene in biological materials. For this purpose, samples containing 3-methoxyhydroxy benzene are extracted with methyl acetate for 45 minutes three times. Pooled extracts are treated with KOH solution in ethanol, then solvent is removed by evaporation at 18-22°C. The residue is treated several times with acetone containing HCl in excessive quantity relative to alkali in the residue. Acidified acetone extracts are pooled, treated with aqueous NaON solution to generate excess of alkaline medium and acetone is removed in the air flow at a temperature of 18-22°C. The aqueous alkaline solution is diluted with water, acidified to pH = 2-3 with 24% HCl, extracted with diethyl ester and saturated with Na₂SO₄ to remove water residues. The extract is evaporated in the air flow at a temperature of 18-22°C and tested by chromatography using a macrocolumn with silica gel KCC 3 80/120 µm. The mixture is eluated with the mixture hexane-dioxane-propanol-2 in volume ratio 20:5:1. Eluate fractions containing the test substance are pooled and concentrated to 10 ml. The obtained residue is alkalified with NaOH solution with pH = 12-13 and then acidified to pH = 2-3 with 24% HCl and then extracted with dichloromethane and saturated with Na₂SO₄ to remove water residues. Dichloromethane extract is treated with N-methyl-N-trimethylsilyl-trifluoroacetamide for 20 min at 60°C to obtain trimethylsilyl 3-methoxyhydroxybenzene derivative. The test is performed by the method of chromate-mass-spectrometry. Separation is carried out using capillary column (L=25 m, d= 0.2 mm), with stationary phase (5% phenyl-methylpolysiloxane) in helium flow 0.6 ml/min. The initial temperature of the column oven is 70°C and it is maintained for 3 min, then the temperature is programmed from 70°C to 290°C with change rate of 20°C per min, the final column temperature is maintained for 10 min. The injector temperature is 250°C, the detector interface temperature is 300°C. The signal is recorded using mass-selective detector in the mode of electron impact by the ionizing electron beam of 70 eV. The quantity of trimethylsilyl 3-methoxyhydroxy benzene derivative is calculated using the preliminarily plotted calibrating curve by comparing peak areas.

EFFECT: invention provides for increased method sensitivity and may be used at sanitary and epidemiologic centers, chemical and toxicological, expert criminalistic and veterinary laboratories.

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