GB/T 38349-2019Determination of N-methyl pyrrolidone in rubber shoes and sports footwear (English PDF)

3.1 Methanol

chromatographically pure.

3.2 N-methylpyrrolidone standard substance

CAS No. 872-50-4, purity >=99%.

3.3 Glass sample bottle

40mL, good sealing.

3.4 Disposable sterile syringe

2mL.

3.5 Organic phase needle filter

pore size 0.22 µm.

3.6 N-methylpyrrolidone standard solution, 1000mg/L. Weigh accurately 10mg of N-methylpyrrolidone standard substance in a 10mL volume

In a measuring flask, dissolve with methanol (3.1) and make up to volume to obtain a standard solution of 1000 mg/L.

Note. This solution is packaged in a brown storage bottle and stored in a refrigerator at 0 °C ~ 4 °C, protected from light, and the validity period is 12 months.

3.7 N-methylpyrrolidone standard stock solution, 20mg/L. Transfer 0.5mL N-methylpyrrolidone standard with a concentration of 1000mg/L

The quasi solution (3.6) to a 25 mL volumetric flask was made up to the mark with methanol (3.1) to obtain a standard stock solution of 20 mg/L.

Note. This solution is packaged in a brown storage bottle and stored in a refrigerator at 0 °C ~ 4 °C, protected from light, and the validity period is 3 months.

3.8 N-methylpyrrolidone standard working solution. Take 5 10mL volumetric flasks and add 0.25mL, 0.5mL, 1.0mL,

2.5mL and 5mL N-methylpyrrolidone standard stock solution (3.7) with a concentration of 20mg/L, make up to the mark with methanol (3.1), get

To standard working solutions with concentrations of 0.5 mg/L, 1 mg/L, 2 mg/L, 5 mg/L, and 10 mg/L, respectively, and 20 mg/L of N-methyl

The pyrrolidone standard stock solution (3.7) constitutes six standard working solutions of different concentrations.

4.1 Gas chromatograph-mass spectrometer (GC-MS)

EI source.

4.2 Chromatographic column

capillary column (30m × 0.25mm × 0.25µm, DB-WAX column or equivalent).

4.3 Analytical balance

accuracy of 0.1mg.

4.4 Ultrasonic generator

equipped with a temperature controller, the power is not less than.200W.

4.5 Adjustable pipette

Volume adjustable, range 50µL ~.200µL,.200µL ~ 1000µL, 0mL ~ 5mL, 0mL ~ 10mL.

4.6 Volumetric flask

10mL, 25mL.