Petroleum products and hydrocarbon compounds-determination of sulfur content Wickbold combustion method (7)

9.

9.

See Table 1

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Only use analytical reagents and distilled water or water of equivalent purity for analysis

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9.

9.

a.

b.

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9.
2.
4.
1 Pipette solution d (9.
2.
2.
4) 1.
0, 3.
0, 5.
0, 7.
0, 10.
0mL, and pour into 5 50mL volumetric flasks respectively
.

9.
2.
4.
2 Add 3.
0mL hydrochloric acid (9.
2.
2.
2) to each volumetric flask , add water to the mark, and mix thoroughly.
Then transfer them all into a 100mL beaker one by one, and then use a pipette to pipette 10.
0±0.
1mL ethanol.
-Glycerol mixture (9.
2.
2.
3) is poured into each beaker
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Then put them in a constant temperature bath at 25±0.
1℃, take them out, stir with an electromagnetic stirrer for 3min, and then put them back into the constant temperature bath for 4min.
Use a 50mm cuvette to measure the absorbance A with water as the reference liquid at 450nm
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The test solution in the cuvette should be poured back into the original beaker in full, and then kept at a constant temperature of 25±0.
1°C for 10 minutes, add 0.
30±0.
01g barium chloride (9.
2.
2.
1), and stir with an electromagnetic stirrer for 6 minutes , Constant temperature for 4 minutes, and then use a 50mm cuvette to measure the absorbance with water as the reference liquid, and calculate the (BA) value
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9.
2.
4.
3 The standard curve can be obtained by plotting the absorbance (BA) value and the sulfur content (ug)
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In daily analysis, a standard sample whose concentration level is close to the middle range of the calibration curve is used as a single-point test to check and correct the possible deviation of the standard curve
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2.
5 Operation steps

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2.
5.
1 Transfer the full amount of the absorption liquid in the ampoule (13) to a 300mL Erlenmeyer Erlenmeyer flask, cover the top of the bottle with the surface, and place it on the heating plate under the condition that no sulfide smoke escapes.
Open flame) evaporate and concentrate to about 30mL, then quantitatively transfer it to a 50mL volumetric flask, and then operate according to 9.
2.
4.
2 operation steps, calculate the absorbance (BA) value, check the sulfur content from the standard curve ( ug)
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Perform a blank test at the same time.
If the sulfur content of the reagent blank reading exceeds 4ug, the instrument needs to be cleaned and the test repeated
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9.
2.
5.
2 Calculation

When calculating the sulfur content, when expressed in mg/kg, use formula (5); when expressed in mg/m³ (under 0℃ and 101.
3kPa pressure), use formula (6); when expressed in %(m/m) , Using formula (7)
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In the formula: m ₀ —— sample mass, g;

m ₁ ——The mass of sulfur obtained from the standard curve, g;

V ₂ ——The volume of absorption liquid taken, mL;

V ₃ ——Total volume of absorption liquid, mL;

V _.
4 - sample volume at 0 ℃, 101.
3kPa pressure, L
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