Chlorphenesin is a white to off-white crystalline powder. It is a broad-spectrum bacteriostatic agent and preservative. It has a good bacteriostatic and bactericidal effect on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, mold and other microorganisms. Currently, chlorphenesin is permitted in cosmetics as a preservative, but studies have shown that chlorphenesin may cause shortness of breath in infants. Therefore, infants are advised not to use chlorphenesin-containing products. Part 7: Finger Paints – Requirements and Measurement Methods” and the domestic GB 6675.14-2014 “Toy Safety Part 14: Finger Paint Requirements and Test Methods” allows chlorphenesin to be used as a restricted preservative, and specifies the maximum allowable use The concentration is 0.15%.
A liquid chromatographic detection method for chlorphenesin in a toy material, comprising the following steps:
(1) Prepare standard solution and fit standard curve equation
Weigh 0.05g (accurate to 0.0001g) of chlorophenesin, add methanol-water (50:50, v/v), dissolve by ultrasonic and transfer it to a 50mL volumetric flask, use methanol-water solution to make up to the mark, shake Evenly, prepare a standard stock solution with a mass concentration of 1000 mg/L;
Pipette 5.0mL of 1000mg/L standard stock solution into a 100mL volumetric flask, dilute to the mark with methanol-water (50:50, v/v) solution, shake well, and prepare an intermediate work with a mass concentration of 50mg/L standard solution;
Pipette 0.20, 1.00, 2.00, 10.0 mL of chlorphenesin intermediate working standard solution and 1.00, 2.50, 5.00 mL of standard stock solution into a 10 mL volumetric flask, and dilute with methanol-water (50:50, v/v) to the mark, shake well to obtain a series of concentration standard solutions with mass concentrations of 1.00, 5.00, 10.0, 50.0, 100, 250 and 500 respectively;
Taking the peak area as the ordinate (Y) and the mass concentration in the standard solution as the abscissa (X), perform linear regression, and the regression equation of chlorphenesin is Y=4.11(e+003)X-1.46(e+004) .
(2) Sample processing
Weigh 1.0g of the sample (accurate to 0.0001g) into a 10mL colorimetric tube with a stopper, add the extract (methanol-water (50:50, v/v)) to the mark and seal it with a parafilm, vortex for 1.0min , ultrasonically extracted for 20-35min, then filtered through a 0.22μm filter membrane, and the filtrate was used as the sample solution to be tested for later use;
(3) Chromatographic detection
Use methanol-water as mobile phase to carry out gradient elution according to Table 1, use C-18 column as chromatographic column (100mm×2.1mm, 1.7μm), use photodiode array (PDA) detector, detection wavelength 280nm (chlorophene The detection wavelength of ether), the flow rate is 0.2 mL/min, the column temperature is 30 °C, the injection volume is 1 μL, and the measured peak area is substituted into the regression equation of step (1) to obtain the mass concentration of chlorphenesin in the sample.
Table 1 Mobile phase gradient elution table
In the range of (1.000～500) mg/L, the peak area has a good linear relationship with the mass concentration, and the correlation coefficient is 0.9995. The spiked recoveries at different levels were 98.3%-104%, and the relative standard deviation (ie precision) was 0.51%-2.13%.
