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Determination of formaldehyde in cosmetics by HPLC

2020-04-03 3891649

Formaldehyde has been identified as carcinogenic and teratogenic substances by the World Health Organization. It is recognized as a source of allergy and one of the potential strong mutagens. Formaldehyde has a great impact on human health. Cosmetics directly affect the skin. The content of formaldehyde is the key to human health.
In this method, the content of free formaldehyde in cosmetics is determined by post column Derivatization High performance liquid chromatography, which is suitable for water, cream and gel cosmetics.
The following is the determination method of free formaldehyde content in cosmetics
Experimental principle
The free formaldehyde in the sample was separated by high performance liquid chromatography, derivatized after column, detected at 420nm wavelength, qualitatively determined according to retention time, quantitatively determined according to peak area, and calculated by standard curve method. When 0.2g sample is taken, the detection concentration of free formaldehyde is 0.003%, and the minimum quantitative concentration is 0.005%.
Reagents and materials
All reagents used are analytically pure or above specifications, and water is grade I water specified in GB / T 6682 (unless otherwise specified).
The formaldehyde standard substance aqueous solution shall be calibrated before use.
Phosphoric acid, analytical pure.
Ammonium acetate, chromatographically pure.
Glacial acetic acid, analytical pure.
Acetylacetone, analytical pure.
Dichloromethane, analytical pure.
Phosphoric acid solution: take 2ml of phosphoric acid, slowly add it to 998ml of water, and mix well.
Post column derivative solution: weigh 62.5g of ammonium acetate, add 7.5ml of glacial acetic acid, 5ml of acetylacetone, add water to 1000ml, shake well. The solution can be used effectively for 3 days.
Formaldehyde series standard solution: accurately measure the amount of formaldehyde standard substance aqueous solution and dilute it with phosphoric acid solution to 1 μ g/mL, 2 μ g/mL, 5 μ g/mL, 10 μ g/mL, 20 μ g/mL and 50 μ g/mL standard series solutions. Temporary use and ready to use.
Instruments and equipment
Lc-10t high performance liquid chromatograph
Post column derivator.
Vortex oscillator.
Sample treatment
Weigh 0.2g (accurate to 0.001g) of the sample into a 10ml stoppered colorimetric tube, add phosphoric acid solution to the scale, vortex treatment for 1 minute, centrifugation at 5000rpm for 5min, take the supernatant and filter it through a 0.45 μ m microporous filter membrane (water phase), the filtrate as the solution to be tested, and determine it as soon as possible.
If necessary, take the supernatant and add 10ml of dichloromethane, shake it, take the upper solution after standing and layering, filter it with 0.45 μ m microporous filter membrane (water phase), and the filtrate is used as the solution to be tested.
Chromatographic conditions
Column: C18 (250 × 4.6m m × 5 μ m);
Mobile phase: phosphoric acid solution;
Flow rate: 1.0ml/min;
Column temperature: 20 ℃;
Detection wavelength: 420nm;
Injection volume: 10 μ L;
The flow rate of post column derivative solution: 0.5ml/min;
Derivative temperature: 100 ℃.
Chromatographic determination
Under the condition of chromatography, take the formaldehyde series standard solution as the sample, carry on the liquid chromatography analysis, take the series standard solution concentration as the abscissa, the Formaldehyde Derivative peak area as the ordinate, carry on the linear regression, establish the standard curve, get the regression equation.
Take 10 μ l of the solution to be tested, conduct chromatographic analysis, determine the nature according to the retention time and spectrogram, measure the peak area of formaldehyde derivative, and get the mass concentration of free formaldehyde in the solution to be tested according to the standard curve. Calculate the content of free formaldehyde in the sample.
Lc-10t high performance liquid chromatograph
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