GB/T 39998-2021Paper, board and paper products—Determination of alkylphenol polyethoxylates—HPLC-MS method (English PDF)

7.1 Paper and cardboard

Take at least 10g sample and cut it to pieces below 5mm×5mm. The cardboard can also be crushed by a crusher (5.4) to crush the sample into Flocculent or fragments below 5mm.

7.2 Paper products

7.2.1 Samples that are not easy to cut

For diapers (sheets, pads) and sanitary napkins (pads) and other samples that are not easy to be cut and mixed, at least one complete sample should be taken and a crusher should be used (5.4) After crushing into flocculent shape, weigh the sample after mixing. The final sampling mass is not less than 10g.

7.2.2 Wipes

For wet wipes, in order to ensure uniform sampling, take one each from the upper, middle and lower parts of the two packs of wet wipes, and accurately weigh the total mass of 6 wet wipes m1 (Accurate to 0.1mg), placed on a clean aluminum box or watch glass, put the container with the sample in a constant temperature drying oven (5.5), at 50 °C Dry in a constant temperature drying box for 3 hours. In order to ensure that the sample is dried as soon as possible, the sample can be placed in multiple containers, and the sample should be avoided as much as possible. Weigh the total mass of the dried sample m2 (accurate to 0.1mg), cut it to pieces below 1cm×1cm, and mix them.

8.1 Extraction

Weigh 2g of the prepared sample (accurate to 0.1mg) into a 40mL sample bottle or Erlenmeyer flask, add 20mL methanol (4.2), Ultrasonic constant temperature water bath (5.2), ultrasonic treatment at room temperature for 30min. Then transfer the sample extract, and use 20 mL of methanol for the residue Repeat the extraction once, combine the extraction solutions in a 50mL volumetric flask, and dilute to the mark with methanol. Filtered by 0.22µm filter membrane (4.6), Measured by high performance liquid chromatography mass spectrometer (5.1).

8.2 Determination

8.2.1 Reference conditions for high performance liquid chromatography

The reference conditions of HPLC are as follows.

a) Chromatographic column. C18, 50mm×3.0mm, inner diameter 2.7µm, or equivalent;

b) Mobile phase. methanol : 10mmol/L ammonium acetate solution (4.3) = 80:20;

c) Flow rate. 0.4mL/min;

d) Column temperature. 35°C;

e) Injection volume. 5µL.

8.2.2 Reference conditions for mass spectrometry

The mass spectrometry reference conditions are as follows.

a) Ionization method. cation electrospray ionization source (ESI);

b) Ion scan mode. Scan (qualitative), SIM (quantitative);

c) Capillary voltage. 3500V;

d) Nozzle voltage. 500V;

e) Drying gas temperature. 325°C;

f) Dry air flow. 7L/min;

g) Atomizing gas pressure. 0.31MPa (45psi);

h) Sheath gas temperature. 325°C;

i) Sheath gas flow. 10L/min;

j) Monitoring ion range. m/z=150~1500.

8.2.3 Qualitative and quantitative analysis of high performance liquid chromatography mass spectrometry

8.2.3.1 Qualitative analysis

Analyze the standard curve working solution (6.4) and the sample solution to be tested according to the analysis conditions of 8.2.1 and 8.2.2.

The retention time and the characteristic qualitative ions of alkyl phenol polyoxyethylene ether (see Appendix A) are used for qualitative analysis. In the actual measurement process of the sample, It is necessary to use Scan (scan ion range m/z=150~1500), that is, the mass spectrum of the sample should contain the characteristic ion of [M NH4] A series of adduct ion peaks of the ions, these adduct ion peaks present a certain normal distribution, and each adduct ion peak has a difference in adjacent masses 44. It can be determined that the compound is an alkylphenol polyoxyethylene ether, and other means can be used to confirm if necessary.

8.2.3.2 Quantitative analysis

Inject the standard curve working solution (6.4) and the sample solution to be tested into the high performance liquid chromatography mass spectrometer (5.1), (Or NPEOs) concentration is the abscissa, OPEs (or NPEOs) characteristic ion (see Appendix A) mass chromatographic peak area is the ordinate, plotted Standard working curve.

Obtain the concentration of OPEs (or NPEOs) in the sample solution to be tested according to the standard working curve. If the concentration exceeds the standard working curve Scope, it can be analyzed after diluting with methanol to an appropriate concentration.

Refer to Appendix B for the total ion chromatogram and mass spectrum of alkylphenol polyoxyethylene ether liquid chromatography mass spectrometry.

8.3 Blank test

Except for no samples, proceed in accordance with 8.1 and 8.2.

9.1 Calculation of alkylphenol polyoxyethylene ether content in wet tissue samples

Calculate the content of alkylphenol polyoxyethylene ether in wet wipes according to formula (1).

Xi = (c1 - c0) × V × f × m2 / (m × m1) (1)

Where:

Xi --- The content of alkylphenol polyoxyethylene ether in the sample, in milligrams per kilogram (mg/kg);

c1 --- The concentration of the alkylphenol polyoxyethylene ether corresponding to the sample solution in the standard curve, in milligrams per liter (mg/L);

c0 --- The concentration of alkylphenol polyoxyethylene ether corresponding to the blank solution in the standard curve, in milligrams per liter (mg/L);

V --- The constant volume of the sample, the unit is milliliters (mL);

f --- dilution factor;

m2 --- The total mass of 6 wet tissue samples after drying, in grams (g);

m --- sample sampling quality, the unit is grams (g);

m1 --- The total mass of 6 wet tissue samples, in grams (g).

9.2 Calculation of alkylphenol polyoxyethylene ether content in other samples

Calculate the content of alkyl phenol polyoxyethylene ether according to formula (2).

Where:

Xi --- The content of alkylphenol polyoxyethylene ether in the sample, in milligrams per kilogram (mg/kg);

c1 --- The concentration of the alkylphenol polyoxyethylene ether corresponding to the sample solution in the standard curve, in milligrams per liter (mg/L);

c0 --- The concentration of alkylphenol polyoxyethylene ether corresponding to the blank solution in the standard curve, in milligrams per liter (mg/L);

V --- The constant volume of the sample, the unit is milliliters (mL);

f --- dilution factor;

m --- sample sampling quality, the unit is grams (g).