CIRCULAR

ON THE NATIONAL TECHNICAL REGULATION ON FOOD PROCESSING AIDS - SOLVENTS

Pursuant to the Law of food safety dated 17 June 2010 and the Government's Decree No. 38/2012/ND-CP dated 25 April 2012 on details for the enforcement of certain articles of the Law of food safety;

Pursuant to the Law of technical regulations and standards dated 29 June 2006 and the Government's Decree No. 127/2007/ND-CP dated 01 August 2007 on details for the enforcement of certain articles of the Law of technical regulations and standards;

Pursuant to the Government’s Decree No. 63/2012/ND-CP dated 31 August 2012 on functions, missions, authority and organizational structure of the Ministry of Health;

At the request of the Head of Vietnam Food Administration;

Minister of Health issues the Circular on the National technical regulation on food processing aids - solvents.

Article 1. This Circular is enclosed with:

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Article 2. This Circular comes into effect as of 01 September 2016.

Article 3. Head of Vietnam Food Administration, heads of agencies under the Ministry of Health, agencies of the Ministry of Health, directors of provincial Health Departments and entities concerned are responsible for enforcing this Circular./.

FOR MINISTER
DEPUTY MINISTER




Nguyen Thanh Long

QCVN 18-1:2015/BYT

ON THE NATIONAL TECHNICAL REGULATION ON FOOD PROCESSING AIDS - SOLVENTS

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QCVN 18-1:2015/BYT is compiled by the Committee for drafting of national technical regulations on food additives and processing aids, is presented by Vietnam Food Administration, is reviewed by the Ministry of Science and Technology, and is promulgated under the Circular No. … /2015/TT-BYT dated ... 2015 by the Minister of Health.

ON THE NATIONAL TECHNICAL REGULATION ON FOOD PROCESSING AIDS - SOLVENTS

I. GENERAL

1. Scope of regulation

This Regulation governs specifications and administrative requirements for solvents used as food processing aids (referred to as solvents).

2. Regulated entities

This Regulation shall apply to:

2.1. Organizations and individuals importing, producing and selling solvents in Vietnam.

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3. Acronym

In this Regulation, these acronyms are construed as follows:

3.1. C.A.S (Chemical Abstracts Service) number refers to registry numbers of chemical substances identified by the American Chemical Society.

3.2. TS (test solution) means reagent liquid.

3.3. ADI stands for acceptable daily intake.

3.4. INS stands for the international numbering system for food additives.

4. Reference

4.1. JECFA monograph 1 - Vol. 4: Food additive specifications, Volume 4 on analytical methods, test procedures and laboratory solutions used by (or referenced) in the food additive specifications; compiled by JECFA; issued by FAO in 2006.

4.2. TCVN 6469:2010 Food additives - Food additives - Methods for evaluating appearance and physical properties;

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4.4. TCVN 8900-1:2012 Food additives - Determination of inorganic components. Part 1: Water content (Karl Fischer titrimetric method);

4.5. TCVN 8900-2:2012 Food additives - Determination of inorganic components - Part 2: Loss on drying, ash, water-insoluble matter and acid-insoluble matter contents.

4.6. TCVN 8900-6:2012 Food additives. Determination of inorganic components - Part 6: Measurement of antimony, barium, cadmium, chromium, copper, lead and zinc by flame atomic absorption spectrometry.

4.7. TCVN 8900-7:2012 Food additives. Determination of inorganic components – Part 7: Measurement of antimony, barium, cadmium, chromium, copper, lead and zinc by inductive coupled plasma atomic emission spectrometric method (ICP-AES).

4.8. TCVN 8900-8:2012 Food additives. Determination of inorganic components – Part 8: Measurement of lead and cadmium by graphite furnace atomic absorption spectrometry.

II. SPECIFICATIONS, METHODS OF ASSAY, SAMPLING AND LABELING

1. Specifications and methods of assay

Specifications and methods of assay for solvents are defined in annexes to this Regulation:

1.1.

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Specification and method of assay for acetone

1.2.

Annex 2:

Specification and method of assay for isoamyl acetate

1.3.

Annex 3:

Specification and method of assay for butan-1,3-diol

1.4.

Annex 4:

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1.5.

Annex 5:

Specification and method of assay for cyclohexane

1.6.

Annex 6:

Specification and method of assay for diethyl ether

1.7.

Annex 7:

Specification and method of assay for ethyl acetate

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Annex 8:

      Specification and method of assay for petroleum ether

1.9.

Annex 9:

Specification and method of assay for toluene

1.10.

Annex 10:

Specification and method of assay for benzyl alcohol

1.11.

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Specification and method of assay for butan-2-ol

1.12.

Annex 12:

Specification and method of assay for dichloromethane

1.13.

Annex 13:

Specification and method of assay for hexanes

Methods of assay as described in this Regulation are not mandatory. Different methods of assay with equivalent degree of precision may be employed.

2. Sampling

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3. Labeling

Labeling of solvents abides by the Government’s Decree No. 89/2006/ND-CP dated 30 August 2006 on product labeling, the joint Circular No. 34/2014/TTLT-BYT-BNNPTNT-BCT dated 27 October 2014 by the Minister of Health, Minister of Agriculture and Rural development and Minister of Industry and Trade on guidelines for labeling of foodstuffs, food additives and prepackaged food processing aids and relevant laws.

III. ADMINISTRATIVE REQUIREMENT

1. Declaration of conformity

1.1. The conformity of solvents must be declared according to this Regulation.

1.2. The method and procedure for declaration of conformity shall be governed by Article 6 and Article 7 of the Government’s Decree No. 38/2012/ND-CP dated 25 April 2012 on details for the enforcement of certain articles of the Law on food safety, by Article 4, Article 5, Article 7 and Article 9 of the Circular No. 19/2012/TT-BYT dated 09 November 2012 by the Minister of Health on guidelines for declaration of conformity and compliance with food safety regulations and by relevant laws.

2. Inspection and actions against violations of law

Competent government authorities shall inspect and take actions against importers, producers and sellers of solvents, who violate technical and administrative stipulations in this Regulation and relevant laws.

IV. RESPONSIBILITIES OF ORGANIZATIONS AND INDIVIDUALS

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2. Entities shall only be permitted to import, produce and sell solvents upon their receipt of a Certificate of declaration of conformity from Vietnam Food Administration and their fulfillment of relevant laws in effect.

V. ENFORCEMENT

1. Vietnam Food Administration shall lead and cooperate with authorities concerned to enforce this Regulation.

2. Vietnam Food Administration, according to its administrative devoirs, shall be responsible for proposing to the Ministry of Health the amendments and supplements to this Regulation.

3. If international guidelines for methods of assay and laws referred to in this Regulation are amended, supplemented or replaced, revised documents shall prevail.

Annex 1

SPECIFICATION AND METHOD OF ASSAY FOR ACETONE

1. Synonym

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2. Definition

Chemical name

Propan-2-one

C.A.S number

67-64-1

Chemical formula

C₃H₆O

Structural formula

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Formula weight

58.08

3. Description

Clear, colorless, volatile, highly flammable liquid with a characteristic odor, free from sediment and suspended matter

4. Functional use

Extraction solvent, flavoring agent

5. Specification

5.1. Qualitative

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Solubility

Miscible in all proportions with water and with ethanol

Specific gravity

d²⁰₂₀ : 0.790 - 0.793

Refractive index

n²⁰_D : 1.358 - 1.360

5.2. Purity

Distillation range

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Non-volatile residue

Not more than 0.001% (w/w)

Acidity

Not more than 0.002% (w/w) (calculated as acetic acid)

Phenol

Not more than 0.001% (w/w)

Readily oxidizable substances

Pass the test

5.3. Content of C₃H₆O

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6. Method of assay

6.1. Qualitative test

Solubility

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

Refractive index

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6.2. Purity test

Distillation range

TCVN 6469:2010

Non-volatile residue

TCVN 8900-2:2012

Acidity

Place 100 ml of freshly boiled and cooled distilled water (neutralized to phenolphthalein TS) and a few anti-bumping granules in a 500 ml conical flask of boro-silicate glass and boil gently for 5 minutes to eliminate carbon dioxide. Cool slightly and add 100 ml of the sample. Boil gently for a further 5 minutes. Seal the flask with a stopper carrying a soda-lime tube. When cold, remove the stopper then add 0.5 ml phenolphthalein TS and examine for alkalinity. If not alkaline, titrate with sodium hydroxide solution using a micro-burette.

Calculate the acidity as acetic acid (%, w/w) by this formula

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where

T = volume (ml) of 0.1 N sodium hydroxide solution consumed

d = specific gravity of the sample

Phenol

Place 3 ml of the sample in a crucible and evaporate to dryness at 60^oC, add 3 drops of a solution of 0.1 g sodium nitrite dissolved in 5 ml of sulfuric acid and allow to stand for 2 to 3 minutes. Carefully add 3 ml 2 N sodium hydroxide. No color is produced.

Readily oxidisable substances

30 ml of the sample does not discolor 0.1 ml of 3% m/v freshly prepared aqueous potassium permanganate solution when shaken and allowed to stand at 20^oC for 15 minutes.

6.3. Quantitative test

Weigh accurately about 1 g of the sample in a flask containing 20 ml of water, and add water to 1,000 ml. Place 10 ml of the solution in a glass flask sealed by a stopper, add 25 ml of 0.1 N sodium hydroxide, and allow to stand for 5 minutes. Add 25 ml of 0.1 N iodine, seal with the stopper, allow to stand in a cold and dark place for 10 minutes, then add 30 ml of 1 N sulfuric acid. Titrate the excess iodine with sodium thiosulfate, using starch TS as the indicator. Perform a blank test in the same manner as the sample and make any necessary correction. Each ml of 0.1 N iodine is equivalent to 0.9675 mg of C₃H₆O.

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Annex 2

SPECIFICATION AND METHOD OF ASSAY FOR ISOAMYL ACETATE

1. Synonym

Amyl acetate, isoamyl ethanoate

2. Definition

A mixture of acetic acid esters of pentanols

Chemical name

3-methylbutyl ethanoate (principal component)

C.A.S number

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Chemical formula

C₇H₁₄O₂

Structural formula

Formula weight

130.19

3. Description

Colorless clear liquid having a characteristic fruit-like odor

4. Functional use

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5. Specification

5.1. Qualitative

Solubility

Slightly soluble in water, insoluble in glycerol, practically insoluble in propylene glycol.

Soluble in ethanol, diethyl ether, ethyl acetate, most fixed oils and mineral oils.

Specific gravity

d²⁵₂₅: 0.868 - 0.878

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n²⁰_D : 1.400 - 1.404

5.2. Purity

Acidity

Not more than 1

Non-volatile residue

Not more than 7 mg/100 ml

Distillation range

Not less than 99% v/v, distills between 135^oC to 143^oC

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Not more than 2.0 mg/kg

5.3. Content of C₇H₁₄O₂

Not less than 95.0% C₇H₁₄O₂

6. Method of assay

6.1. Qualitative test

Solubility

TCVN 6469:2010

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TCVN 6469:2010

Refractive index

TCVN 6469:2010

6.2. Purity test

Acidity

TCVN 6471:2010

Non-volatile residue

TCVN 8900-2:2012

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TCVN 6469:2010

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

6.3. Quantitative test

Weigh accurately about 0.8 g of the sample and proceed as directed under Ester Determination in JECFA Monograph 1 Vol. 4, using 65.10 as the equivalence factor (e) in the calculation

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Annex 3

SPECIFICATION AND METHOD OF ASSAY FOR BUTAN-1,3-DIOL

1. Synonym

1,3-Butylene glycol, b-butylene glycol

2. Definition

Chemical name

Butan-1,3-diol

C.A.S number

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Chemical formula

C₄H₁₀O₂

Structural formula

Formula weight

90.12

3. Description

Clear, colorless, odorless, hygroscopic, viscous liquid

4. Functional use

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5. Specification

5.1. Qualitative

Solubility

Miscible with water, acetone and ether.

Soluble in fixed oils, ethanol, ether

Specific gravity

1.004 - 1.006

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Distillation range

200°C - 215°C

Water

Not more than 0.5% (w/w)

Lead

Not more than 2.0 mg/kg

5.3. Content of C₄H₁₀O₂

Not less than 99.0% (w/w)

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6.1. Qualitative test

Solubility

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

6.2. Purity test

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TCVN 6469:2010

Water

TCVN 8900-1:2012

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

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Proceed as directed in JECFA Monograph 1 Vol.4, using 0.2 g of the sample

Annex 4

SPECIFICATION AND METHOD OF ASSAY FOR BUTAN-1-OL

1. Synonym

Butyl alcohol, n-butyl alcohol, 1-hydroxybutane, n-butanol, n-propyl carbinol, NBA

2. Definition

Chemical name

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C.A.S number

76-36-3

Chemical formula

C₄H₁₀O

Structural formula

Formula weight

74.12

3. Description

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4. Functional use

Extraction solvent, flavoring agent

5. Specification

5.1. Qualitative

Solubility

Soluble in water, miscible with ethanol and ether.

Specific gravity

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5.2. Purity

Distillation range

116°C - 118°C

Non-volatile residue

Not more than 2 mg/100 ml

Water

Not more than 0.1 %

Acidity

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Aldehyde and ketone

Not more than 0.2% (w/w)

Other alcohols, ethers, and volatile impurities

Not more than 0.5%, with not more than 0.1% of any single impurity.

Lead

Not more than 2 mg/kg

5.3. Content of C₄H₁₀O

Not less than 99.5%

6. Method of assay

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6.1. Qualitative test

Solubility

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

6.2. Purity test

Distillation range

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Non-volatile residue

TCVN 8900-2:2012

Water

TCVN 8900-1:2012

Acidity

To 60 g of the sample add a few drops of phenolphthalein TS, and titrate with 0.1 N potassium hydroxide (KOH) to a pink end-point that persists for at least 15 seconds. Not more than 0.3 ml potassium hydroxide (KOH) is required.

Aldehyde and ketone

- Under Aldehyde and Ketone Determination in JECFA Monograph 1 Vol.4;

- Use 10 g of the sample and 36.06 as the equivalence factor (e) in the calculation

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JECFA Monograph 1 Vol.4

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

6.3. Quantitative test

Using the procedures for gas chromatography described in the General Methods in JECFA Monograph 1 Vol.4, establish the following conditions:

Column: 1.8 m length, 6 mm diameter, stainless steel, packed with 10% P.E.G. 400 on Chromosorb W (60/80 mesh), or equivalent.

Carrier gas: Helium, at flow rate of 45 ml/min

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- Temperature of injection port: 150^oC

- Temperature of column: 90^oC

- Temperature of detector: 150^oC

Inject 1 to 5 ml of sample, obtain chromatogram, then determine the content of each constituent by the method of area normalization.

Annex 5

SPECIFICATION AND METHOD OF ASSAY FOR CYCLOHEXANE

1. Synonym

Hexahydrobenzene

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Chemical name

Cyclohexane

C.A.S number

110-82-7

Chemical formula

C₆H₁₂

Structural formula

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84.16

3. Description

Colorless, clear, flammable liquid with characteristic odor

4. Functional use

Extraction solvent

5. Specification

5.1. Qualitative

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Insoluble in water, miscible with ethanol and ether

Specific gravity

0.776 - 0.780

5.2. Purity

Distillation range

80°C - 82°C

Non-volatile residue

Not more than 1 mg/100 ml

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Not more than 10 mg/kg

Benzene

Not more than 0.1 % (v/v)

Polycyclic aromatic hydrocarbons

The following absorbance limits per cm of optical path length shall not exceed

Wavelength (nm)

280-289

290-299

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360-400

Absorbance

0.15

0.12

0.08

0.02

Lead

Not more than 2 mg/kg

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Not less than 99.5% (w/w)

6. Method of assay

6.1. Qualitative test

Solubility

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

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Distillation range

TCVN 6469:2010

Non-volatile residue

TCVN 8900-2:2012

Sulphur

JECFA Monograph 1 Vol.4

Benzene

JECFA Monograph 1 Vol.4 (Aromatic Hydrocarbon Determination)

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JECFA Monograph 1 Vol.4

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

6.3. Quantitative test

Proceed as directed under the gas-liquid chromatographic method for determination of polycyclic aromatic hydrocarbons in JECFA Monograph 1 Vol.4 and calculate the content by the method of area percentage (area normalization).

Annex 6

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1. Synonym

Ether, ethyl ether

2. Definition

Diethyl ether normally contains appropriate stabilizers such as pyrogallol or BHT. Manufacturers should indicate on the label the specific stabilizer(s) used and the amount added. Typical levels are in the range of 3-7 mg/l.

Chemical name

Diethyl ether, diethyl oxide, 1,1'-oxybisethane.

C.A.S number

60-29-7

Chemical formula

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Structural formula

Formula weight

74.12

3. Description

Colorless, clear, very mobile liquid, with a characteristic odor; very volatile and flammable.

4. Functional use

Extraction solvent

5. Specification

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5.1. Qualitative

Solubility

Insoluble in water, miscible with ethanol

Specific gravity

0.714 - 0.716

5.2. Purity

Distillation range

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Non-volatile residue

Not more than 2 mg/100 ml

Water

Not more than 0.2%

Acidity

Pass the test

Aldehyde and ketone

Pass the test

Peroxides

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Lead

Not more than 2 mg/kg

6. Method of assay

The test for peroxides must occur prior to other tests. It is dangerous to distill or evaporate diethyl ether in the absence of a test for peroxides.

6.1. Qualitative test

Solubility

TCVN 6469:2010

Specific gravity

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6.2. Purity test

Distillation range

TCVN 6469:2010

Non-volatile residue

TCVN 8900-2:2012

Water

TCVN 8900-1:2012

Acidity

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Aldehyde and ketone

Place 2 ml of Nessler's TS in a stoppered tube of about 12-ml capacity and about 1.5-cm diameter and fill the tube with the sample. Insert the stopper, shake vigorously for 10 seconds, and allow to stand in the dark for 5 minutes. If no color or turbidity is produced at this stage, the sample is considered to have complied with the test. If color or turbidity is produced, after ensuring that the sample complies with the test for peroxides, distil more quantity of the sample in a fractionating column and repeat the test. No color or turbidity is produced.

Peroxides

The color produced by iodine liberated by the action of organic peroxides on potassium iodide is compared with that of a standard iodine solution. Place 8 ml of 10 % potassium iodide solution in a stoppered tube of 12-ml capacity and about 1.5 cm diameter. Fill the tube to the brim with the sample, place the stopper in position so that no air bubble is enclosed, shake vigorously, and allow to stand in darkness for 30 minutes. The yellow color produced, if any, must not be darker than that of 0.5 ml of 0.001 N iodine diluted with 8 ml of the potassium iodide solution.

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

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SPECIFICATION AND METHOD OF ASSAY FOR ETHYL ACETATE

1. Synonym

Acetic acid ethyl ester, ethyl ethanoate

2. Definition

Chemical name

Ethyl acetate

C.A.S number

141-78-6

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C₄H₈O₂

Structural formula

Formula weight

88.11

3. Description

Colorless, transparent liquid having a fruity odor

4. Functional use

Carrier solvent, flavoring agent

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5.1. Qualitative

Refractive index

n²⁰_D: 1.371 - 1.376

Specific gravity

Acidity

Not more than 5.0

Boiling point

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5.2. Content of C₄H₈O₂

Not less than 99.0%

6. Method of assay

6.1. Qualitative test

Refractive index

TCVN 6469:2010

Specific gravity

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Acidity

TCVN 6471:2010

Boiling point

TCVN 6469:2010

6.2. Quantitative test

Transfer about 1.5 g, accurately weighed in a tared stoppered weighing bottle, to a suitable flask, then add 50.0 ml of 0.5 N sodium hydroxide, and reflux on a steam bath for 1 hour. Allow to cool, add phenolphthalein TS and titrate the excess sodium hydroxide with 0.5 N hydrochloric acid. Perform a blank determination, and make any necessary correction. Each ml of 0.5 N sodium hydroxide is equivalent to 44.06 mg of C₄H₈O₂.

Annex 8

SPECIFICATION AND METHOD OF ASSAY FOR PETROLEUM ETHER

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Petroleum spirits, petroleum ether

2. Definition

Light petroleum fractions boiling between 25^oC and 105^oC. Mixed paraffinic (normal and iso) and cycloparaffinic hydrocarbons.

ADI of 0-5 mg/kg body weight

3. Description

Clear, colorless, mobile, highly flammable liquid with a characteristic petroleum-like odor.

4. Functional use

Extraction solvent

5. Specification

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5.1. Qualitative

Solubility

Insoluble in water, soluble in ethanol

5.2. Purity

Non-volatile residue

Not more than 2 mg/100 ml

Sulphur

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Benzene

Not more than 0.05 % (v/v)

Aromatic hydrocarbons

Not more than 0.3% (v/v) (including benzene)

Polycyclic aromatic hydrocarbons

The sample must meet the following absorbance limits:

Wavelength (nm)

Maximum absorbance per cm (path length)

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280-289

290-299

300-359

360-400

0.15

0.12

0.08

0.02

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Not more than 200

Lead

Not more than 2 mg/kg

6. Method of assay

6.1. Qualitative test

Solubility

TCVN 6469:2010

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Non-volatile residue

TCVN 8900-2:2012

Sulphur

JECFA Monograph 1 Vol.4

Benzene

Aromatic Hydrocarbons Determination in JECFA Monograph 1 Vol.4

Aromatic hydrocarbons

Aromatic Hydrocarbons Determination in JECFA Monograph 1 Vol.4

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JECFA Monograph 1 Vol.4

Bromine index

Principle

A known mass of the sample dissolved in a suitable solvent is titrated with standard bromide-bromate solution. The end point is indicated by a dead stop electrometric titration apparatus, when the presence of free bromine causes a sudden change in the electrical conductivity of the system. The bromine index is the number of mg of bromine that will react with 100 g of the sample under the conditions of the test.

Apparatus

- Dead-stop electrometric titration apparatus: Any dead-stop apparatus may be used if incorporating a high-resistance polarizing current supply capable of maintaining approximately 0.8 V across two platinum electrodes and with sensitivity such that a voltage change of approximately 50 mV at these electrodes is sufficient to indicate the end point.

- Titration vessel: A jacketed glass vessel of approximately 150-ml capacity of such a form that can be maintained conveniently at 1^oC to 5^oC. A pair of platinum electrodes spaced not more than 5 mm apart, shall be mounted to extend well below the liquid level. Stirring shall be done by a mechanical or electromagnetic stirrer and shall be rapid, but not so vigorous as to draw air bubbles down to the electrodes.

- Burettes: 10-ml and 50-ml capacity

- Iodine number flasks: stoppered, 500-ml capacity

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Bromide-bromate solution 0.05 N: Dissolve 5.1 g of potassium bromide and 1.4 g of potassium bromate in water and dilute to 1,000 ml. Standardize to four significant figures as follows: Place 50 ml of acetic acid and 1 ml of hydrochloric acid TS in a 500 ml iodine number flask. Chill the solution in an ice bath for approximately 10 minutes and with constant swirling of the flask, add from a 50 ml burette 40 to 45 ml of bromide-bromate solution (estimated to the nearest 0.01 ml) at a rate such that the addition takes between 90 and 120 seconds. Stopper the flask immediately, shake the contents, place it again in the ice bath, and add 5 ml of 15% potassium iodide solution in the lip of the flask. After 5 minutes, remove the flask from the ice bath and allow the 15% potassium iodide solution to flow into the flask by slowly removing the stopper. Shake vigorously, add 100 ml of water in such a manner as to rinse the stopper, lip, and walls of the flask, and titrate promptly with 0.05 N sodium thiosulfate. Near the end of the titration, add starch and titrate slowly to the disappearance of the blue color.

Calculate the normality of the bromide-bromate solution as follows:

Where:

N₁ = normality of the bromide-bromate solution

A₁ = ml of the bromide-bromate solution

N₂ = normality of the Na₂S₂O₃ solution

A₂ = ml of the Na₂S₂O₃ solution required for titration of the bromide-bromate solution

- Titration solvent: prepare 1,000 ml of titration solvent by mixing the following materials: glacial acetic acid (714 ml), carbon tetrachloride (134 ml), methanol (134 ml), and sulfuric acid (18 ml of 1 + 5).

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Switch on the titrimeter and allow the electrical circuit to stabilize according to the manufacturer's instructions. Cool the titration vessel to 0^oC - 5^oC by circulating a suitable coolant through the jacketed titration vessel. Add 110 ml of the titration solvent and 8 to 10 g of the sample. Switch on the stirrer and adjust to a rapid stirring rate, but not so rapid as to draw air bubbles into the solution. Allow the contents to cool to 0^oC - 5^oC and maintain this temperature throughout the titration. Add the bromide-bromate solution in small increments from a 10 ml burette until the detector (magic eye or potentiometric) indicates that the end point has nearly been reached. Continue adding 0.1 ml of the reagent at a time until the detector indicates a stable end point has been reached (end point lasting more than 30 seconds). Repeat the determination but without the addition of the sample; less than 0.1 ml of the bromide-bromate solution should be required.

Calculation

Calculate the bromine index from

Bromine index =

Where

T₁ = ml of the bromide-bromate solution required for the titration of the sample

T₂ = ml of the bromide-bromate solution required for the blank titration

N = normality of the bromide-bromate solution

W = weight of the sample (g)

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TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

Annex 9

SPECIFICATION AND METHOD OF ASSAY FOR TOLUENE

1. Synonym

Toluol, phenylmethane

2. Definition

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Chemical name

Toluene, methylbenzene

C.A.S number

108-88-3

Chemical formula

C₇H₈

Structural formula

Formula weight

...

...

...

3. Description

Clear, colorless liquid with a characteristic odor

4. Functional use

Extraction solvent

5. Specification

5.1. Qualitative

Solubility

...

...

...

Specific gravity

0.864 - 0.870

5.2. Purity

Distillation range

From 110.6^oC to 111.6^oC

Color

Not darker than color standard n^o 20

Non-volatile residue

...

...

...

Sulfur compounds

Pass the test

Non-aromatic substances

Not more than 0.2% (v/v)

Benzene

Not more than 0.5% (v/v)

Lead

Not more than 2 mg/kg

5.3. Content of C₇H₈

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...

...

6. Method of assay

6.1. Qualitative test

Solubility

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

6.2. Purity test

...

...

...

Distillation range

TCVN 6469:2010

Color

JECFA Monograph 1 Vol. 4

Non-volatile residue

TCVN 8900-2:2012

Sulfur compounds

Negative for hydrogen sulfide and sulfur dioxide by the following test:

Reagents

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- Potassium iodate solution (10 g of KlO₃/ 100 ml)

- Starch paper: Dip strips of filter paper in starch solution and let them dry

Procedure

Make a qualitative test for hydrogen sulfide (H₂S) and sulfur dioxide (SO₂) upon the performance of the distillation test. This is done by hanging a strip of filter paper moisten with the lead acetate solution and a strip of starch paper moisten with the potassium iodate solution on the end of the condenser tube. The strips are so placed that they are suspended in the upper part of the receiving cylinder so that drops of condensate pass between the strips without touching them. If, at the end of the test, the lead acetate paper shows discoloration, H₂S is present, but not SO₂. If the lead acetate paper shows no discoloration but the starch iodate paper develops a blue color, SO₂ is present but not H₂S. S. If neither paper shows discoloration, neither H₂S nor SO₂ is present.

Non-aromatic substances

Proceed as directed under the Aromatic Hydrocarbons Determination in JECFA Monograph 1 Vol. 4 and calculate the content of non-aromatic substances by the method of area percentage (area normalization)

Benzene

Proceed as directed under the Aromatic Hydrocarbons Determination in JECFA Monograph 1 Vol. 4

Lead

...

...

...

TCVN 8900-7:2012

TCVN 8900-8:2012

6.3. Quantitative test

JECFA Monograph 1 Vol. 4

Annex 10

SPECIFICATION AND METHOD OF ASSAY FOR BENZYL ALCOHOL

1. Synonym

Phenylcarbinol, phenylmethyl alcohol, benzenemethanol, alphahydroxytoluene

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...

...

2. Definition

Chemical name

Benzyl alcohol, phenylmethanol

C.A.S number

100-51-6

Chemical formula

C₇H₈O

Structural formula

...

...

...

Formula weight

108.14

3. Description

Colorless, clear liquid, with a faint, aromatic odor

4. Functional use

Flavoring agent, carrier solvent

5. Specification

5.1. Qualitative

...

...

...

Solubility

Soluble in water, ethanol and ether

Refractive index

n²⁰_D: 1.538 - 1.541

Specific gravity

d²⁵₂₅: 1.042 - 1.047

Infrared absorption

Pass the test

5.2. Purity

...

...

...

Distillation range

Not less than 95% v/v, distills between 202^oC to 208^oC

Lead

Not more than 2 mg/kg

Acidity

Not more than 0.5

Aldehydes

Not more than 0.2% (v/v) (as benzaldehyde)

Peroxides

...

...

...

Chlorinated organic compounds

Pass the test

5.2. Content of C₇H₈O

Not less than 98.0%

6. Method of assay

6.1. Qualitative test

Solubility

...

...

...

TCVN 6471:2010

Refractive index

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

Infrared absorption

The infrared spectrum of the sample corresponds with the reference infrared spectrum.

6.2. Purity test

...

...

...

Distillation range

TCVN 6469:2010

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

Acidity

TCVN 6471:2010

Aldehydes

...

...

...

Transfer into two test tubes:

Control tube: 2 ml of the control solution.

Sample tube: 2 ml of the sample,

To the two tubes, add 3 ml of distilled water and 0.5 ml of a saturated solution of dinitrophenylhydrazine in diluted hydrochloric acid, then cap the tubes, shake steadily and allow to stand for 10 minutes. Add 5 ml of 95% ethanol and 2 ml of a 10% potassium hydroxide solution (KOH) and homogenize.

Red brown color (if any) that develops in the sample tube must not be more intense than that in the control tube.      

Peroxides

Flush out, with CO₂, a ground glass necked 100-ml flask fitted with a cool air condenser. Introduce 1 ml of the sample, 2 ml of chloroform, 0.1 g of potassium iodide and 20 ml of a mixture of chloroform and glacial acetic acid (ratio 1:2 v/v). Fit the condenser to the flask and warm with small flame to initiate boiling within 30 seconds. Maintain boiling for exactly 30 seconds upon the appearance of vapors in the condenser. Stop warming and cool it immediately in iced water, and add through the condenser 40 ml of CO₂-free distilled water. Titrate the liberated iodine with a 0.005N solution of sodium thiosulfate and record the ml of sodium thiosulfate used as V_m. Perform the same operation without the sample and record the ml of sodium thiosulfate used as V₁.

The difference V_m - V_t must be less than 1 (equivalent to 40 mg of peroxide per litre, expressed as oxygen).

Chlorinated organic compounds

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6.3. Quantitative test

Weigh about 1 g (with precision by mg) of the sample, then proceed as directed under the method for Hydroxyl Value in JECFA Monograph 1 Vol. 4. Calculate the percentage of benzyl alcohol by the formula:

Where:

A is ml of KOH solution required for titration of free acid;

B is ml of KOH solution required for titration of the reagent blank;

C is the weight of the sample used for free acid determination;

S is ml of KOH solution required for titration of the acetylated sample;

W is the weight of the sample used for acetylation;

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Annex 11

SPECIFICATION AND METHOD OF ASSAY FOR BUTAN-2-OL

 1. Synonym

Secondary butyl alcohol, 2-hydroxybutane

2. Definition

Chemical name

2-Butanol, butan-2-ol

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...

78-92-2

Chemical formula

C₄H₁₀O

Structural formula

Formula weight

74.12

3. Description

Colorless, clear, slightly viscous, flammable liquid, with a characteristic odor.

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...

...

Extraction solvent, flavoring agent

5. Specification

5.1. Qualitative

Solubility

Freely soluble in water, miscible with ethanol and ether.

Specific gravity

0.806 - 0.809

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...

Distillation range

From 98.5^oC to 100.5^oC

Non-volatile residue

Not more than 2 mg/100 ml

Water

Not more than 0.2% w/w

Acidity

Not more than 0.003% w/w (as acetic acid)

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...

Not more than 0.3% w/w (as butanal)

Lead

Not more than 2.0 mg/kg

6. Method of assay

6.1. Qualitative test

Solubility

TCVN 6469:2010

...

...

...

TCVN 6469:2010

6.2. Purity

Distillation range

TCVN 6469:2010

Non-volatile residue

TCVN 8900-2:2012

Water

TCVN 8900-1:2012

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...

To 60 g of the sample add a few drops of phenolphthalein TS, and titrate with 0.1 N potassium hydroxide (KOH) to a pink end-point which persists for at least 15 seconds. Not more than 0.3 ml of potassium hydroxide (KOH) is required.

Aldehyde and ketone

- Proceed as directed in JECFA Monograph 1 Vol. 4

- Use 10 g of the sample and the equivalence factor (e) of 36.06.

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

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SPECIFICATION AND METHOD OF ASSAY FOR DICHLOROMETHANE

1. Synonym

Methylene chloride, Methylene dichloride

2. Definition

Dichloromethane (DCM) derives from the chlorination of methane, during which other chlorinated methane derivatives may be formed. Propylene oxide, cyclohexane, and/or 2-methyl-2-butene are added as stabilizers. Purity depends on the amount of C₂ and higher hydrocarbons in the methane and the extent of chlorination. Therefore, small amounts of several other chlorinated compounds may be present. Dichloromethane is commonly recovered from extraction processes and several grades of quality are commonly found in commerce. Dichloromethane is stable when dry though it hydrolyzes in the presence of water.

Chemical name

Dichloromethane

C.A.S number

75-09-2

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CH₂CI₂

Structural formula

Formula weight

84.93

3. Description

Clear colorless non-flammable liquid

4. Functional use

Extraction solvent

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5.1. Qualitative

Solubility

Sparingly soluble in water, miscible with ethanol and ether

Refractive index

n²⁰_D: 1.423 - 1.425

Specific gravity

d²⁵₂₅: 1.323 - 1.327

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Water

Not more than 0.02 %

Distillation range

from 39^oC to 41^oC

Non-volatile residue

Not more than 2 mg/100 ml

Free chlorine

Pass the test

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Not more than 0.002% (w/w) (as HCL)

Alkalinity

Not more than 0.01% (w/w) (as NaOH)

Lead

Not more than 1 mg/kg

5.3. Content of CH₂CI₂

Not less than 99.0%

6. Method of assay

...

...

...

Solubility

TCVN 6469:2010

Refractive index

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

6.2. Purity test

...

...

...

TCVN 8900-1:2012

Distillation range

TCVN 6469:2010

Non-volatile residue

TCVN 8900-2:2012

Free chlorine

Shake 10 ml of the sample steadily for 2 minutes with 10 ml of 10% potassium iodide solution and 1 ml of starch TS. A blue color does not appear in the water layer.

Acidity

Place 100 ml of freshly boiled and cooled distilled water (neutralized to phenolphthalein TS) in a 500-ml glass-stoppered conical flask. Add another 100 ml of the sample and shake steadily. Allow the layers to separate, transfer the aqueous phase into an Erlenmeyer flask, add 0.5 ml of phenolphthalein TS and titrate with 0.1 N sodium hydroxide to a pink color that persists. Calculate any content (%, w/w) of acid in the sample thus found as hydrochloric acid. 1 ml of 0.1 N NaOH is equal to 0.00365 g of HCl.

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Place 100 ml of freshly boiled and cooled distilled water (neutralized to phenolphthalein TS) in a 500-ml glass-stoppered conical flask. Add another 100 ml of the sample and shake steadily. Allow the layers to separate, transfer the aqueous phase into an Erlenmeyer flask, add 0.5 ml of phenolphthalein TS and titrate with 0.1 N hydrochloric acid to a pink color that persists. Calculate alkalinity (%, w/w) in the sample thus found as sodium hydroxide. 1 ml of 0.1 N HCl is equal to 0.004 g of NaOH.

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

6.3. Quantitative test

Principle:

Test material is injected into a gas chromatograph equipped with capillary gas chromatographic columns and a flame ionization detector. Quantification of dichloromethane, contaminants and stabilizers is made by comparing peak areas against external standards.

Apparatus:

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Instrumental conditions:

Injector: 150^oC

Detector: 250^oC

Oven: 40^oC, isothermal

Carrier gas: He 4.4 ml/min

Split flow: 98 ml/min  

Standard:

Sufficient amount of each constituent below is added to the high purity DCM to make the approximate solution:

Methyl chloride: 0.014 % (w/w)

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Ethyl chloride: 0.0084

Propylene oxide: 2.4

Vinylidene chloride: 0.0098

Trans-1,2-Dichloroethylene: 0.017

Chloroform: 0.012

Cyclohexane: 0.047

2-metyl-2-butene: 0.009

The solution is contained in a glass bottle fitted with a silicone rubber septum. Constituents are injected and weighed by syringe (with precision by mg). They are injected into the DCM container through the septum then the syringe is re-weighed to determine the amounts added. The DCM used to make standards must be assayed to determine the possible presence of contaminants prior to use.

Procedure

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Methyl chloride: 2.8

Vinyl chloride: 3.0

Ethyl chloride: 3.5

Propylene oxide: 4.1

2-Methyl-2-butene: 4.5

Vinylene chloride: 4.6

Dichloromethane: 5.3

Trans-1,2-Dichloroethylene: 5.9

Chloroform: 8.7

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Carbon tetrachloride: 12.0

Annex 13

SPECIFICATION AND TESTING METHOD FOR HEXANES

1. Synonym

Hexanes

2. Definition

The term “hexanes" refers hydrocarbons with 6 carbon atoms in chains broken in the process of petroleum cracking. Typically hexanes contain mainly n-hexane, 2-methylpentane, 3-methylpentane or mixtures of these with smaller amounts of n-pentane, isopentane, cyclohexane, n-heptane, dimethylbutanes and methylcyclopentane.

Chemical name

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...

Chemical formula

C₆H₁₄

Formula weight

86.18

3. Description

Clear colorless highly flammable liquid with a characteristic petroleum-like odor; free from sediment and suspended matter

4. Functional use

Extraction solvent

5. Specification

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5.1 Qualitative

Solubility

Insoluble in water, soluble in ether, alcohol and acetone

Refractive index

n²⁰_D: 1.381 - 1.384 (pure n-hexane: about 1.375)

Specific gravity

d²⁰₂₀: 0.665 - 0.687 (pure n-hexane: about 0.660)

5.2. Purity

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...

Distillation range

95% v/v distils between 64^oC to 70^oC

pH

Neutral to methyl orange (pH indicator)

Non-volatile residue

Not more than 0.0005% w/v

Sulfur

Not more than 5.0 mg/kg

Benzene

...

...

...

Lead

Not more than 1.0 mg/kg

Polycyclic aromatic hydrocarbons (PAHs)

Pass the test

6. Method of assay

6.1 Qualitative test

Solubility

...

...

...

Refractive index

TCVN 6469:2010

Specific gravity

TCVN 6469:2010

6.2. Purity test

Distillation range

TCVN 6469:2010

pH

...

...

...

Non-volatile residue

TCVN 8900-2:2012

Sulfur

JECFA Monograph 1 Vol.4

Benzene

Principle:

Internal standard: methyl ethyl ketone (MEK) is added to the test hexane which is then introduced into a gas chromatograph equipped with two columns connected by a flow diversion valve (Figure 1).The specimen passes first through a column packed with a non-polar phase (column A), methyl silicone, which separates the non-polar hydrocarbons. After octane has eluted, the flow is reversed and diverted to the column containing a highly polar phase (column B). Components which have not eluted through column A are thus diverted to column B which separates the aromatic and non-aromatic compounds. The eluted components are detected by a flame ionization detector and recorded on a strip chart. The peak areas are measured and the concentration of each component is calculated by reference to the internal standard.

Apparatus:

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Column A - Made of stainless steel, 0.8 m in length, by 3.2 mm outside diameter, packed with 10% methyl silicone coated on 60-80 mesh acid washed diatomaceous earth.

Column B - Made of stainless steel, 4.6 m in length, by 3.2 mm outside diameter, packed with 25% 1,2,3-Tris(2- cyanoethoxy) propane (TCEP) coated on 80-100 mesh acid washed diatomaceous earth.

Join column A and column B (as shown in Figure 1) using a flow diverting valve. Adjust the helium gas flow through both columns to approximately 40 ml/min. Set the valve in the backflush position and set the flow rate for column B to 40 ml/min (Figure 2).

Fig.2 Flow Switching System

Materials and reagents:

Methyl Ethyl Ketone (MEK) >99.9 %

Benzene >99%

Isooctane >99%

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Calibration:

Determine time required before changing the valve, which varies for each column system and must be determined experimentally as follows: prepare a mixture of 5 volume % isooctane in n-nonane. With the system in the forward flow mode as shown in Figure 2a, inject 1 ml of the mixture of isooctane and n-nonane and allow both compounds to elute. Measure the time in seconds from the injection until all the isooctane but none of the n-nonane has eluted. One half of the measured time approximates the time to switch the backflush valve. Make additional runs until a chromatogram of isooctane and little or none of n-nonane is obtained.

Standardization:

Standard solutions: Prepare 7 standard solutions covering the range of 0 to 1 volume % benzene in a 100 ml volumetric flask, diluted, filled to 100 ml with isooctane to make standard solutions with the following content of benzene:

Volume %

ml

1

1

0.5

...

...

...

0.25

0.25

0.1

0.1

0.05

0.05

0.01

0.01

0.005

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...

Calibration solutions: Accurately measure 0.5 ml of MEK into a 100-ml volumetric flask, fill to the mark with the first standard solution and mix thoroughly. Repeat with each of the other standard solutions. Under the conditions established above, chromatograph each of the calibration solutions after injecting approximately 3 ml.

Calibration: Measure the peak areas of the benzene and of MEK. Calculate the ratio of the benzene peak area to the MEK peak area. Plot the concentration of benzene versus the ratio. The calibration plot must be linear. Determine the retention time for each component for future identification.

Procedure

Test solution: Accurately measure 0.5 ml of MEK into a 100 ml volumetric flask. Fill to the mark with the material under test and mix well. Chromatograph a specimen from the test solution. Identify the peaks of benzene and the internal standard MEK from the retention time of the standards. The order of elution is non-aromatic hydrocarbons, benzene, MEK, and toluene. Measure peak areas of benzene and MEK.

Calculation:

Calculate the ratio of peak area of benzene to the peak area of MEK. Read from the calibration curve the peak volume % of benzene corresponding to the calculated peak ratio. If the results are desired on a weight basis, convert to weight % as follows:

Benzene, weight % = V/D x 0.8844

Where:

V is volume % of benzene,

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...

Lead

TCVN 8900-6:2012

TCVN 8900-7:2012

TCVN 8900-8:2012

Polycyclic aromatic hydrocarbons (PAHs)

Transfer 25 ml of the sample to a 125 ml separator and add 25 ml of hexane. Mix and add 5 ml of dimethyl sulfoxide. Shake steadily for 1 minute and allow to stand until two clear layers are formed. Transfer the lower layer to a second separating funnel, add 2 ml of hexane and shake the mixture steadily. Allow to stand until two clear layers are formed. Separate the lower layer and measure its absorbance over the range 260 nm to 420 nm. Add 5.0 ml of dimethyl sulfoxide with 25 ml of hexane then shake steadily for 1 minute. Prepare a reference solution in trimethyl pentane containing 7.0 mg of naphthalene (per litre) and measure the absorbance of that solution at the wavelength of 275 nm using trimethylpentane as a blank. At wavelengths in the range 260 nm to 420 nm, the absorbance of the test solution is equal to one-third that of the reference solution at 275 nm.

Use hexane, dimethyl sulfoxide and trimethylpentane in quality specified for ultraviolet spectrophotometry.