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GB/T 8294-2008: Natural rubber latex concentrate -- Determination of boric acid content
Status: Valid GB/T 8294: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Standard Title (Description) | Status | PDF |
| GB/T 8294-2008 | English | 94 |
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Natural rubber latex concentrate -- Determination of boric acid content
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GB/T 8294-2008
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| GB/T 8294-2001 | English | 279 |
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Natural rubber latex concentrate -- Determination of boric acid content
| Obsolete |
GB/T 8294-2001
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| GB/T 8294-1987 | English | RFQ |
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Natural rubber latex concentrate--Determination of boric acid content
| Obsolete |
GB/T 8294-1987
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PDF similar to GB/T 8294-2008
Basic data | Standard ID | GB/T 8294-2008 (GB/T8294-2008) | | Description (Translated English) | Natural rubber latex concentrate -- Determination of boric acid content | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | B72 | | Classification of International Standard | 83.060 | | Word Count Estimation | 5,574 | | Date of Issue | 2008-05-15 | | Date of Implementation | 2008-11-01 | | Older Standard (superseded by this standard) | GB/T 8294-2001 | | Adopted Standard | ISO 1802-1992, IDT | | Regulation (derived from) | National Standard Approval Announcement 2008 No.8 (Total No.121) | | Issuing agency(ies) | General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China, Standardization Administration of the People's Republic of China | | Summary | This standard specifies the determination of concentrated natural latex boric acid content. This standard applies to the production of Hevea brasiliensis latex Natural rubber latex concentrate. | GB/T 8294-2008: Natural rubber latex concentrate -- Determination of boric acid content---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Natural rubber latex concentrate. Determination of boric acid content
ICS 83.060
B72
National Standards of People's Republic of China
GB/T 8294-2008/ISO 1802.1992
Replacing GB/T 8294-2001
Natural rubber latex concentrate Determination of boric acid content
(ISO 1802.1992, IDT)
Posted 2008-05-15
2008-11-01 implementation
Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China
Standardization Administration of China released
Foreword
This standard is identical with ISO 1802.1992 "Natural rubber latex concentrate - Determination of boric acid content" (in English).
For ease of use, the editorial changes made the following standard.
--- "This International Standard" be replaced by "this standard";
--- Delete foreword international standards;
--- References GB/T 8290 sampling in Chapter 6, which is standard with ISO 1802.1992 is no technical difference in the respective sections.
This standard replaces GB/T 8294-2001 "Natural rubber latex concentrate - Determination of boric acid content."
It was compared to the 2001 edition of this standard and editorial changes.
The standard proposed by China Petroleum and Chemical Industry Association.
This standard by the National Standardization Technical Committee rubber natural rubber and rubber Technical Committee.
This standard was drafted. Chinese Academy of Tropical Agriculture Institute of Agro-band, the Ministry of Agriculture Food Quality Supervision and Testing Center
(Zhanjiang).
The main drafters of this standard. Lv Mingzhe, more than peace, Chen Chenghai.
This standard was first released in July 1987, in July 2001 the first amendment.
GB/T 8294-2008/ISO 1802.1992
Natural rubber latex concentrate Determination of boric acid content
Warning. Use of this standard shall have a person experiences regular lab work. This standard does not point out all possible security issues.
The user's responsibility to take appropriate safety and health practices and to ensure compliance with the conditions relevant national regulations.
1 Scope
This standard specifies the method for determination of concentrated natural latex boric acid content.
This standard applies to the Brazilian rubber tree latex production concentrated natural rubber latex.
2 Normative references
The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent
Amendments (not including errata content) or revisions do not apply to this standard. However, according to research encourages the parties to the agreement
Study whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.
GB/T 8290 Natural rubber latex concentrate sampling (GB/T 8290-1987, eqv ISO 123. 1985)
Principle 3
Containing boric acid pH is adjusted to approximately 0.02g sample of latex 7.50, then boric acid is substantially non-dissociated state. Then added over
The amount of mannitol to form a strongly acidic acid - mannitol complex, thus releasing the equivalent of boric acid in the latex amount of hydrogen ions, the pH value
decline. Alkali the pH of the sample return to 7.50, based on the amount of base added boric acid content can be measured.
4 Reagents
This standard uses only recognized analytical reagent, distilled water or water of equivalent purity.
4.1 hydrochloride, mass fraction of 2% solution.
4.2 stabilizer solution, containing a mass fraction of 5% of the ethylene oxide condensate type nonionic stabilizing agent.
4.3 mannitol.
4.4 boric acid solution
Weigh about 5g of boric acid (H3BO3), accurate to 1mg, dissolved in water and diluted to 1000mL in a volumetric flask.
4.5 standard solution of sodium hydroxide, Ba (NaOH) ≈0.05mol/L.
Calibration solution 4.5.1
Draw 5mL boric acid solution (4.4) with a pipette (5.2) into a 250mL beaker, stabilizer was added 2mL (4.2) and
50mL water. The solution is measured using a pH meter (5.1) the pH, such as pH value of more than 5.5, the edge constantly stirring, hydrochloric acid was added dropwise a solution of
(4.1), the pH is reduced to 5.5 to 2.5 range. The solution was allowed to stand 15min, with constant stirring, a burette (5.3) was added sodium hydroxide
Solution (4.5) until pH reaches 7.50. Was added and then continued stirring 4g mannitol (4.3), pH value then decreased. From then titrated
Tube (5.3) accurately titrated with sodium hydroxide solution, the pH returned to record volume of 7.50 required for sodium hydroxide solution.
4.5.2 Calculation of concentration
Sodium hydroxide solution calculated by the formula (1) the concentration of Ba, expressed in moles per liter.
Ba = 0.081 × m1 Vp 1
(1)
Where.
M1 --- 1000mL boric acid solution (4.4) in boric acid mass in grams (g);
Vp 1 --- the pH to return to the desired volume of sodium hydroxide solution 7.50 milliliters (mL).
GB/T 8294-2008/ISO 1802.1992
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