SH/T 0226-1992 Determination of zinc content in additives and additive-containing lubricating oils

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Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0226-92 (confirmed in 2004)
• Chinese name: Determination of zinc content in additives and additive-containing lubricating oils
• English name: not provided in the available source
• Replacement relationship: replaces ZB E60 005-88
• Method composition: This standard includes two methods—the A method (8- hydroxyquinoline method) and the B method (complexometric titration method)
• First publication: 1965 year
• Method A reference adoption: British Petroleum Institute standard IP 117/53 "Determination of Zinc in Lubricating Oils"
• Technical administration unit: Petroleum and Chemical Research Institute technical administration
• Drafting unit: Lanzhou Refining and Chemical General Plant responsible for drafting
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20

2. Scope of application and non-applicability

• This standard specifies the method for determination of zinc content in additives and additive-containing lubricating oils.
• This standard applies to additives and additive-containing lubricating oils.
• A method (8- hydroxyquinoline method): in the determination of zinc, it is not affected by alkaline earth metals, but heavy metals interfere.
• Circumstances where the B method is not applicable: not provided in the available source.

3. Method principle

• A method (8- hydroxyquinoline method): after ashing the sample, dissolving with hydrochloric acid, neutralizing the solution with ammonia water, zinc is determined by the gravimetric method as 8- hydroxyquinoline zinc salt.
• B method (complexometric titration method): burn the sample in a high-temperature furnace, then dissolve the residue with hydrochloric acid, under the condition that pH is 5.5, using xylenol orange as indicator, titrate with EDTA standard titration solution.

4. Reagents and materials (purity / preparation)

A method

• 5.1 Hydrochloric acid: analytical reagent, prepare a solution of 7%(m/m).
• 5.2 Glacial acetic acid: analytical reagent.
• 5.3 Sodium acetate or ammonium acetate: chemical reagent.
• 5.4 8- Hydroxyquinoline: analytical reagent. Preparation: dissolve 2g 8- hydroxyquinoline in 8～10mL glacial acetic acid, dilute to 100mL with distilled water.
• 5.5 Ammonia water: analytical reagent.
• 5.6 95% Ethanol: analytical reagent.
• 5.7 Phenolphthalein indicator: prepare a 10g/L ethanol indicator solution.
• 4.2 Material: quantitative filter paper.

B method

• 12.1 Hydrochloric acid: analytical reagent, prepare solutions of 7%(m/m) and 19%(m/m).
• 12.2 Glacial acetic acid: analytical reagent.
• 12.3 Disodium ethylenediaminetetraacetate (EDTA): analytical reagent.
• 12.4 Anhydrous sodium acetate: analytical reagent.
• 12.5 Sodium chloride: analytical reagent.
• 12.6 Xylenol orange indicator: grind 1g xylenol orange indicator with 100g sodium chloride finely, mix well, store in a ground-glass stoppered bottle.
• 12.7 Methyl orange indicator: prepare a 1g/L indicator solution.
• 12.8 Ammonia water: analytical reagent, prepare a solution of 4%(m/m).
• 12.9 Zinc granules (or zinc sheet).
• 12.10 Anhydrous ethanol: analytical reagent.
• 11.2 Material: quantitative filter paper.

5. Instruments and equipment

A method

• 4.1.1 High-temperature furnace: capable of heating to a constant temperature of 625℃±25℃.
• 4.1.2 Porcelain crucible: 50mL.
• 4.1.3 Beaker: 250mL.
• 4.1.4 Oven: capable of maintaining a constant temperature of 100℃.
• 4.1.5 Gooch funnel: 25 or 50mL (a sintered glass funnel may also be used).

B method

• 11.1.1 Porcelain crucible: 30mL.
• 11.1.2 Conical flask: 250mL.
• 11.1.3 Pipette: 20mL.
• 11.1.4 Burette: 5, 25mL.
• 11.1.5 Graduated cylinder: 10mL.
• 11.1.6 Beaker: 100mL.
• 11.1.7 Volumetric flask: 1000mL.
• 11.1.8 Glass rod with rubber sleeve.
• 11.1.9 High-temperature furnace: capable of heating to a constant temperature of 800℃±25℃.
• 11.1.10 Balance: sensitivity of 0.1mg.
• 11.1.11 Universal electric furnace.

6. Recommended operating conditions

• A method ashing temperature: 625℃±25℃.
• A method drying temperature: 100℃.
• A method precipitation heating temperature: 60℃.
• B method ignition temperature: 800℃±25℃, ignition time 10min.
• B method titration pH: 5.5.
• B method zinc granules/zinc sheet drying temperature: 105～110℃, dry for 5min, cool in desiccator for 30min.
• Other operating conditions are not provided in the available source.

7. Sampling and sample preparation

A method

• 6.1 Weigh 20g sample or an additive sample equivalent to about 0.1g of 8- hydroxyquinoline zinc, weighed to the nearest 0.001g, place in a porcelain crucible. Ash according to GB/T 508. Maintain the ignition temperature at 625℃±25℃ until completely ashed.

B method

• 14.1 Using a porcelain crucible, weigh an additive equivalent to about 10mg zinc or a lubricating oil equivalent to about 2mg zinc, weighed to the nearest 0.0002g.
• 14.2 Roll half a sheet of quantitative filter paper into a cone with an ignition wick, stand it in the porcelain crucible containing the weighed sample, covering most of the sample surface.
• 14.3 First place the porcelain crucible on an electric furnace and heat it; after a large amount of oil fume emerges, ignite the ignition wick of the conical filter paper, burn off the combustible material, then ignite the porcelain crucible in a 800℃ high-temperature furnace for 10min and remove.

8. Analysis procedure

A method

• 6.2 After the crucible has cooled, add a small amount of 7%(m/m) hot hydrochloric acid solution to dissolve the ash, then transfer the solution to a beaker. If there is insoluble matter, filter it.
• 6.3 Add 1 drops of phenolphthalein indicator solution. Neutralize with ammonia water until pink, then add dropwise 7%(m/m) hydrochloric acid solution until the color just disappears. Add a few drops of glacial acetic acid and 3～5g sodium acetate or ammonium acetate. The total volume of the solution shall not exceed 100mL.
• 6.4 Heat the solution to 60℃, add a slight excess of 8- hydroxyquinoline solution. When the upper layer of the precipitate in the beaker appears yellow, it indicates complete precipitation; continue heating to boiling. Filter using a tared Gooch funnel or sintered glass funnel, wash with hot distilled water until the filtrate is no longer yellow.
• 6.5 Dry at 100℃, constant weight, weigh.

B method

• 14.3 (continued) After cooling, first moisten with a small amount of distilled water, then dissolve the ash with about 2mL 19%(m/m) hydrochloric acid solution, place the porcelain crucible on an electric furnace and heat gently for 2～3min, then transfer the solution to a 250mL conical flask, add 2 drops of 1g/L methyl orange indicator solution, adjust the solution to yellow with ammonia water, then adjust to slightly red with 7%(m/m) hydrochloric acid solution. Add 10mL glacial acetic acid-sodium acetate buffer solution, about 20mg xylenol orange indicator. Titrate with a known concentration of EDTA standard titration solution, the endpoint changes from red to yellow.

B method preparation work

• 13.1 c(ZnCl₂)=0.01mol/L zinc chloride standard titration solution: after removing the surface oxide layer from zinc granules or zinc sheet in a 100mL beaker with 19%(m/m) hydrochloric acid solution, quickly wash off residual acid with distilled water, then wash twice with anhydrous ethanol, dry in an oven at 105～110℃ for 5min, remove, cool in a desiccator for 30min. Accurately weigh 0.6538g of the treated zinc granules or zinc sheet into a 1000mL volumetric flask, tilt the volumetric flask at 45°, add 20mL of 19%(m/m) hydrochloric acid solution, after all the zinc has reacted, dilute to the mark with distilled water.
• 13.2 pH is 5.5 glacial acetic acid-sodium acetate buffer solution: weigh 200g anhydrous sodium acetate, add 9mL glacial acetic acid, dilute to 1000mL with distilled water.
• 13.3 c(EDTA)=0.01mol/L standard titration solution: weigh 3.7g disodium ethylenediaminetetraacetate, dissolve in 1000mL distilled water, shake well, then calibrate with zinc chloride standard titration solution. During calibration, use a pipette to draw 20mL zinc chloride standard titration solution into a 250mL conical flask, add 50mL distilled water. Then add 1 drops of 1g/L methyl orange indicator solution, neutralize with 4%(m/m) ammonia water solution until yellow, then adjust with 7%(m/m) hydrochloric acid solution until just red, add 10mL of pH is 5.5 glacial acetic acid-sodium acetate buffer solution, about 20mg xylenol orange indicator, titrate with the EDTA solution of concentration to be calibrated until bright yellow as the endpoint.

9. Qualitative and quantitative and calculation formulas

A method

The zinc content of the sample X[%(m/m)] is calculated according to formula (1):

X = (m₁ × 0.1849 / m) × 100

Where:

• m₁——mass of 8- hydroxyquinoline zinc precipitate, g;
• m—— mass of sample, g;
• 0.1849——8- conversion factor from hydroxyquinoline zinc to zinc.

B method

The actual concentration of EDTA standard titration solution c(EDTA), mol/L, is calculated according to formula (2):

c(EDTA) = c(ZnCl₂) × V₁ / V

Where:

• c(ZnCl₂)——actual concentration of zinc chloride standard titration solution, mol/L;
• V₁——volume of zinc chloride standard titration solution, mL;
• V—— volume of EDTA solution consumed during titration, mL.

The zinc content of the sample X[%(m/m)] is calculated according to formula (3):

X = c(EDTA) × V₁ × 0.06538 × 100 / m = c(EDTA) × V₁ × 6.538 / m

Where:

• c(EDTA)——EDTA actual concentration of standard titration solution, mol/L;
• V₁——volume of EDTA standard titration solution consumed during titration, mL;
• m—— mass of sample, g;
• 0.06538—— mass of zinc in grams equivalent to 1.00mL EDTA standard titration solution [c(EDTA)=1.000mol/L].

10. Precision

A method

• Repeatability: the difference between two results of repeated determinations by the same operator shall not be greater than 0.002%(m/m).

B method

Repeatability: the difference between two results of repeated determinations by the same operator shall not be greater than the following values:

11. Report

• A method (Section 9): take the arithmetic mean of two results of repeated determinations as the zinc content of the test sample.
• B method (Section 17): take the arithmetic mean of two results of repeated determinations as the zinc content of the test sample.

12. Normative references

• GB/T 508 Determination of ash in petroleum products

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick-reference Q&A