GB/T 26393-2011Test methods for harmful matter of burnable incense (English PDF)

3.2 Hydrochloric acid: analytical reagent, 36.0% ~ 38.0%

Use a pulverizer to crush 20 g of sample (for the bamboo incense, remove the bamboo core first); then, pass it through a 0.180 mm (80 mesh/inch) standard sieve; mix well; divide the prepared sample into two equal parts, one for the sample, another one to be tested.

5.1.2 Extraction of sample

Weigh 2 g of sample into a 250 mL Erlenmeyer flask with stopper; put 0.07 mol/L hydrochloric acid solution in a constant temperature water bath oscillator to preheat to 37 °C; transfer 100 mL into the above-mentioned Erlenmeyer flask with stopper; shake for 1 min; use 2 mol/L hydrochloric acid solution to adjust the pH to 1.0 ~ 1.5. Shake in the constant temperature water bath oscillator at 37 °C for 1 h under dark conditions; then, stand still in a water bath at 37 °C for 1 h. Take the supernatant and filter for testing. If necessary, centrifugal separation can be performed at a speed of 2 000 r/min. The separation shall be completed as soon as possible after the above-mentioned storage time, and the time of centrifugation shall not exceed 10 min. The extracted filtrate must be analyzed and tested within 1 working day. At the same time, prepare a blank sample according to the same procedure.

5.2 Test of sample solution

Use an inductively coupled plasma emission spectrometer to test each standard solution in turn from low concentration to high concentration; draw the concentration-absorbance standard curve. Test the absorbance of the sample solution and the blank sample solution; read the corresponding migration concentration from the standard curve.

5.3 Calculation

After testing the concentration of the migration in the sample solution and the blank sample solution, calculate the content of the migration in the sample according to Formula (1).

Where:

X - the content of migration in the sample, in milligrams per kilogram (mg/kg); c1 - the concentration of migration in the sample solution read from the standard curve, in milligrams per liter (mg/L); c0 - the concentration of migration in the blank solution read from the standard curve, in milligrams per liter (mg/L);

V - the volume of the sample solution, in milliliters (mL), which is 100 according to this method; m - sample mass, in grams (g).

5.4 Result processing

The absolute difference between the two parallel test results is not more than 10% of the arithmetic mean of the two measured values, otherwise, it needs to be sampled and tested again. Take the average of the two parallel test results.

6.1 Test conditions

Set a sample point in a closed room of (45±2) m³; the center of location in the room is shown in Figure 1a). The sampling point shall be kept away from vents, and the distance from the wall shall be greater than 0.5 m. The height of the sampling point, in principle, shall be consistent with the height of the human breathing belt; the relative height shall be at 0.5 m ~ 1.5 m.

6.2 Test method

Connect the atmospheric sampler to the porous glass absorption tube and the activated carbon sampling tube; place and evenly distribute them on the diagonal of the room, as shown in Figure 1a); ignite the incense whose mass is (0.6±0.020) g (the mass of bamboo incense is calculated according to the mass after removing the bamboo core); start sampling after the sample is ignited; close the doors and windows during sampling. Perform sampling for 45 minutes at a flow rate of 0.5 L/min. For the collected gas, test the concentration of formaldehyde after combustion according to the method of GB/T 15516-1995; test the concentration of benzene, toluene, and xylene after combustion according to the method of GB/T 11737-1989 method. Take the average of the test results of the three sampling points. Before each sampling, take a blank sample for analysis in the same way as the sample. […]