GB/T 41716-2022 in English

High performance liquid chromatography As the core testing equipment, special attention should be paid to mobile phase ratio and gradient program setting. The physical differences between urushiol and flavonoid components determine that two independent separation strategies should be adopted:

Analysis object	Chromatographic column	Mobile phase system	Detection wavelength (nm)
urushiols	C18 (5μm)	Acetonitrile-water (91:9) isocratic	277
Flavonoids	C18 (5μm)	Methanol/acetic acid gradient elution	248-278

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Sample pretreatment points

It is important to note that the drying process should adopt The vacuum drying oven controls the temperature at 40℃±2℃, and the crushing process requires the use of a 0.18mm aperture sieve plate to ensure sample homogeneity. For urushiol extraction, chloroform-water step extraction is required, and standard samples are recommended to be stored away from light.

The experiment found that every 1℃ increase in column temperature will cause the retention time of urushiol to decrease by 9 seconds. It is recommended to use saturated urushiol + butea superba mixed standard solution to continuously pass the sample through the column before daily testing, and the column efficiency is considered stable when the peak time fluctuation is less than ±0.3min.