GB/T 20373-2021 PDF English
US$110.00 · In stock · Download in 9 secondsGB/T 20373-2021: Determination of acetyl content in modified starch - Titrimetric method Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedureStatus: Valid GB/T 20373: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB/T 20373-2021 | English | 110 |
Add to Cart
|
0-9 seconds. Auto-delivery
|
Determination of acetyl content in modified starch - Titrimetric method
| Valid |
| GB/T 20373-2006 | English | 439 |
Add to Cart
|
3 days
|
Modified starch -- Determination of acetyl content -- Enzymatic method
| Obsolete |
Excerpted PDFs (Download full copy in 9 seconds upon purchase)PDF Preview: GB/T 20373-2021
GB/T 20373-2021: Determination of acetyl content in modified starch - Titrimetric method---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT20373-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.180.20
CCS X 11
GB/T 20373-2021
Replacing GB/T 20373-2006
Determination of Acetyl Content in Modified Starch -
Titrimetric Method
ISSUED ON: MAY 21, 2021
IMPLEMENTED ON: DECEMBER 1, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Principle ... 4
5 Reagents and Materials ... 4
6 Instruments ... 5
7 Methods of Operation ... 5
8 Result Calculation ... 6
9 Precision ... 7
Determination of Acetyl Content in Modified Starch -
Titrimetric Method
1 Scope
This Standard specifies the determination of acetyl content in modified starch through
the titrimetric method.
This Standard is applicable to modified starch that contains acetyl.
2 Normative References
The content of the following documents constitutes indispensable clauses of this
document through normative references in the text. In terms of references with a
specified date, only versions with a specified date are applicable to this document. In
terms of references without a specified date, the latest version (including all the
modifications) is applicable to this document.
GB/T 601 Chemical Reagent - Preparations of Standard Volumetric Solutions
GB/T 603 Chemical Reagent - Preparations of Reagent Solutions for Use in Test
Methods
GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods
3 Terms and Definitions
There are no terms and definitions that need to be defined in this document.
4 Principle
Under alkaline conditions (pH 8.5 or higher), modified starch containing acetyl is
saponified by excess alkali. Use a standard hydrochloric acid titration solution to titrate
the remaining alkali. Through conversion, calculate the acetyl content.
5 Reagents and Materials
Unless it is otherwise specified, the used reagents shall be analytically pure. The water
used for tests shall comply with the requirements of Grade-2 water specified in GB/T
6682.
Use 0.10 mol/L sodium hydroxide solution (5.4) to titrate the specimen solution (7.1.1
or 7.1.2) to slightly red, then, add 25.0 mL of 0.45 mol/L sodium hydroxide solution
(5.5); thoroughly shake it and put on the stopper. Under room-temperature conditions,
on a mechanical oscillator, oscillate it for 30 min, or on a magnetic stirrer (6.2), stir it
for 60 min to perform saponification.
7.3 Sample Titration
After the saponification is completed, remove the stopper; use a washing bottle to rinse
the stopper and the wall of the conical flask. Inject 0.20 mol/L standard hydrochloric
acid titration solution (5.6) into the acid burette (6.3); use it to titrate the specimen, until
the pink color vanishes. Record the volume of the consumed standard hydrochloric
acid titration solution as V1.
7.4 Blank Test
7.4.1 Non-pregelatinized modified starch: take 25.0 mL sodium hydroxide solution (5.5)
as a blank; add 50.0 mL of water and 3 drops of phenolphthalein indicator solution
(5.7); shake it well. Inject 0.20 mol/L standard hydrochloric acid titration solution (5.6)
into the acid burette (6.3); use it to titrate the blank, until the pink color vanishes.
Record the volume of the consumed standard hydrochloric acid titration solution as V0.
7.4.2 Pregelatinized modified starch: take 25.0 mL sodium hydroxide solution (5.5) as
a blank; add 5.0 mL of absolute ethanol (5.3), 100.0 mL of water and 3 drops of
phenolphthalein indicator solution (5.7); shake it well. Inject 0.20 mol/L standard
hydrochloric acid titration solution (5.6) into the acid burette (6.3); use it to titrate the
blank, until the pink color vanishes. Record the volume of the consumed standard
hydrochloric acid titration solution as V0.
8 Result Calculation
The mass fraction w0 of acetyl shall be calculated in accordance with Formula (1):
Where,
V0---the volume of the standard hydrochloric acid titration solution consumed by the
blank, expressed in (mL);
V1---the volume of the standard hydrochloric acid titration solution consumed by the
sample, expressed in (mL);
c---the accurate concentration of the standard hydrochloric acid titration solution,
expressed in (mol/L);
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
Tips & Frequently Asked QuestionsQuestion 1: How long will the true-PDF of English version of GB/T 20373-2021 be delivered?Answer: The full copy PDF of English version of GB/T 20373-2021 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice. Question 2: Can I share the purchased PDF of GB/T 20373-2021_English with my colleagues?Answer: Yes. The purchased PDF of GB/T 20373-2021_English will be deemed to be sold to your employer/organization who actually paid for it, including your colleagues and your employer's intranet. Question 3: Does the price include tax/VAT?Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countriesQuestion 4: Do you accept my currency other than USD?Answer: Yes. www.ChineseStandard.us -- GB/T 20373-2021 -- Click this link and select your country/currency to pay, the exact amount in your currency will be printed on the invoice. Full PDF will also be downloaded/emailed in 9 seconds. Question 5: Should I purchase the latest version GB/T 20373-2021?Answer: Yes. Unless special scenarios such as technical constraints or academic study, you should always prioritize to purchase the latest version GB/T 20373-2021 even if the enforcement date is in future. Complying with the latest version means that, by default, it also complies with all the earlier versions, technically. How to buy and download a true PDF of English version of GB/T 20373-2021?A step-by-step guide to download PDF of GB/T 20373-2021_EnglishStep 1: Visit website https://www.ChineseStandard.net (Pay in USD), or https://www.ChineseStandard.us (Pay in any currencies such as Euro, KRW, JPY, AUD).
Step 2: Search keyword "GB/T 20373-2021".
Step 3: Click "Add to Cart". If multiple PDFs are required, repeat steps 2 and 3 to add up to 12 PDFs to cart.
Step 4: Select payment option (Via payment agents Stripe or PayPal).
Step 5: Customize Tax Invoice -- Fill up your email etc.
Step 6: Click "Checkout".
Step 7: Make payment by credit card, PayPal, Google Pay etc. After the payment is completed and in 9 seconds, you will receive 2 emails attached with the purchased PDFs and PDF-invoice, respectively.
Step 8: Optional -- Go to download PDF.
Step 9: Optional -- Click Open/Download PDF to download PDFs and invoice.
See screenshots for above steps: Steps 1~3 Steps 4~6 Step 7 Step 8 Step 9
|