GB/T 35799-2018 in English

Background of Standard Formulation and Analysis of Technology Evolution

Sodium pyrrolidonecarboxylate is a commonly used cosmetic ingredient with multiple functional properties. With the rapid development of the cosmetics industry, accurate determination of its content is particularly important. This standard adopts high performance liquid chromatography (HPLC), which is a highly sensitive and high-resolution separation technology suitable for trace analysis in complex matrices.

Reagents and Materials

In accordance with the requirements of GB/T 35799-2018, all reagents are analytical or chromatographically pure. These include key reagents such as phosphoric acid, sodium chloride, and methanol, and the preparation method of the standard stock solution is specified in detail.

Instruments and equipment

• Liquid chromatograph: Equipped with UV detector or diode array detector
• Analytical balance: Sensitivity is 0.0001g
• Ultrasonic oscillator: Used for sample extraction
• Centrifuge: Speed ≥10000r/min

Determination steps

The standard specifies a detailed determination process, including sample treatment, standard working curve drawing and sample determination. The key steps are as follows:
1. Sample treatment: Weigh the sample and add it to saturated sodium chloride solution, extract it by ultrasonication and filter it.
2. Determination conditions: Use a C₁₈ reverse phase column, the mobile phase is methanol and potassium dihydrogen phosphate buffer (pH=3.0), and the flow rate is 1.0mL/min.

Result calculation

Calculate the content of sodium pyrrolidonecarboxylate in the sample according to formula (1):
\( X = \frac{c \times V}{m} \times 10^{-4} \)

Recovery and precision

Within the addition concentration range of 0.01%~1.0%, the recovery rate is 90%~110%, and the relative standard deviation is less than 10%.