SH/T 0413-1992 Determination of trace basic nitrogen content in liquid paraffin

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

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

• Standard number: SH/T 0413-92
• Full title: Determination of trace basic nitrogen content in liquid paraffin
• English title: not provided in the available source
• Replacement relationship: replaces SY 2859-82
• First issued: 1975 year (see additional notes)
• 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 determining trace basic nitrogen content in liquid paraffin.
• This standard applies to liquid paraffin.
• Not applicable: not provided in the available source.

3. Method principle

Based on the difference in free strength exhibited by organic bases and inorganic acids in non-aqueous solutions, titrate with perchloric acid-glacial acetic acid standard titration solution and calculate the basic nitrogen content.

4. Reagents and materials (purity / preparation)

• 4.1 Glacial acetic acid: analytical reagent.
• 4.2 Acetic anhydride (the source text source-text extraction writes “acetic drunk”): analytical reagent.
• 4.3 Benzene: analytical reagent.
• 4.4 Perchloric acid: analytical reagent, solution of 70%～72% (m/m).
• 4.5 Methyl violet indicator: prepare a methyl violet glacial acetic acid indicator solution of 1 g/L. Weigh 0.1 g methyl violet and dissolve in 100 mL glacial acetic acid. (The source text source-text extraction writes “1[unreadable character]L”; based on the preparation description, verified as 1 g/L, requires confirmation against the source standard (source-text extraction))
• 4.6 Benzene-glacial acetic acid mixed solution: mix according to the volume ratio of benzene to glacial acetic acid of 1:1.

5. Instruments and equipment

• 5.1 Microburette: 2 mL, graduation 0.01 mL (the source text source-text extraction writes “O.OIML”).
• 5.2 Conical flask: 250 mL (the source text source-text extraction writes “250mLo”).

6. Recommended operating conditions

not provided in the available source (this standard does not list a separate recommended operating conditions section).

7. Sampling and sample preparation

• 6.2.1 specifies: weigh the filtered and dehydrated sample 50 g±0.2 g in a clean, dry 250 mL conical flask.
• Other sampling and preparation details: not provided in the available source.

8. Analytical procedure

8.1 Preparatory work

6.1.1 Preparation and standardization of perchloric acid [c(HC104)=0.02 mol/L]-glacial acetic acid solution:

• Preparation: measure 2 mL perchloric acid, add 250 mL glacial acetic acid, then add 20 mL acetic anhydride, and dilute to 1000 mL with glacial acetic acid.
• Standardization method: weigh reference potassium hydrogen phthalate 0.015 g that has been dried at 105～110 ℃ and cooled, add 50 mL glacial acetic acid, heat to boiling, after cooling add 50 mL benzene and 5 drops of methyl violet indicator, titrate with perchloric acid-glacial acetic acid standard solution; the endpoint is when the purple color completely disappears and turns blue.
• Concentration calculation formula (formula 1): the original formula source-text extraction is incomplete; only the form c = m0 / [204 × (V − V0)] can be identified (the source text source-text extraction writes “[unreadable character]204(V-[unreadable character])x”, requires confirmation against the source standard (source-text extraction)).
  • Where: m0— mass of potassium hydrogen phthalate used in titration, g;
  • 204— molar mass of potassium hydrogen phthalate, g/mol (the source text source-text extraction writes “204.[unreadable sign]~”, requires confirmation against the source standard (source-text extraction));
  • V— volume of perchloric acid-glacial acetic acid standard titration solution used in titrating potassium hydrogen phthalate, mL;
  • V0— volume of perchloric acid-glacial acetic acid solution used in the blank test, mL.

8.2 Analytical procedure

• 6.2.1 In a clean, dry 250 mL conical flask, weigh the filtered and dehydrated sample 50 g±0.2 g, add benzene-glacial acetic acid mixed solution 50 mL, add 5 drops of methyl violet-glacial acetic acid indicator, titrate with perchloric acid-glacial acetic acid standard titration solution; the endpoint is when the purple color disappears and turns blue.
• 6.2.2 Under the same conditions, perform a blank titration with the same reagents.

9. Qualitative and quantitative determination and calculation formula

The basic nitrogen content in the sample X [ppm(m/m)] is calculated according to formula (2):

X = [(V1 − V2) × c × 0.014 / m] × 10^6

Where:

• 0.014— mass of nitrogen, expressed in grams, equivalent to 1.00 mL concentration of [c(HC104)=1.000 mol/L] perchloric acid-glacial acetic acid standard titration solution;
• c— concentration of perchloric acid-glacial acetic acid standard titration solution, mol/L;
• V1— volume of perchloric acid-glacial acetic acid standard titration solution consumed in titrating the sample, mL;
• V2— volume of perchloric acid-glacial acetic acid standard titration solution consumed in titrating the blank reagent, mL;
• m— mass of the sample, g.

Expression of results: report the basic nitrogen content of the sample using ppm(m/m), rounded to one digit after the decimal point.

10. Precision

Repeatability: the difference between two results of repeated determinations shall not exceed the following values.

11. Report

Report the basic nitrogen content of the sample using ppm(m/m), rounded to one digit after the decimal point. (The source text does not list a separate “Report” section; this clause is found in the expression of analytical results in Section 7.)

12. Referenced documents

not provided in the available source (the main text does not list referenced documents).

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 Q&A reference