NY/T 1976-2010 PDF in English
NY/T 1976-2010 (NY/T1976-2010, NYT 1976-2010, NYT1976-2010)
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Water-soluble fertiliers. Determination of organic matter content
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Standards related to (historical): NY/T 1976-2010
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NY/T 1976-2010: PDF in English (NYT 1976-2010) NY/T 1976-2010
AGRICULTURAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 65.080
G 20
Water-soluble fertilizers - Determination of organic
matter content
ISSUED ON: DECEMBER 23, 2010
IMPLEMENTED ON: FEBRUARY 01, 2011
Issued by: Ministry of Agriculture of the PRC
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Principle ... 4
4 Reagents and materials ... 4
5 Apparatus ... 6
6 Analytical procedures ... 6
7 Expression of analysis results ... 7
8 Tolerances ... 8
9 Conversion of mass concentration ... 8
Water-soluble fertilizers - Determination of organic
matter content
1 Scope
This Standard specifies the test method for the determination of organic matter
content of water-soluble fertilizers.
This Standard applies to the determination of organic matter content in liquid or
solid water-soluble fertilizers.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the editions with the dates indicated are
applicable to this document. For the undated references, the latest edition
(including all the amendments) are applicable to this document.
GB/T 8170 Rules of rounding off for numerical values and expression and
judgement of limiting values
HG/T 2843 Chemical fertilizer products - Standard volumetric, standard,
reagent and indicator solutions for chemical analysis
NY/T 887 Liquid fertilizers - Determination of density
3 Principle
USE a quantitative potassium dichromate-sulfuric acid solution to oxidize the
organic carbon in the sample. The remaining potassium dichromate is titrated
with a standard volumetric solution of ferrous sulfate. Based on the reagent
blank, according to the volume of the oxidant consumed before and after the
sample is oxidized, calculate the organic carbon content. The organic matter
content is obtained by the conversion of the carbon coefficient.
4 Reagents and materials
The preparation of reagents, water, and solutions used in this Standard, when
the specifications and preparation methods are not specified, shall comply with
HG/T 2843.
V2 - The volume of standard solution of ferrous sulfate consumed during titration,
in milliliters (mL).
5 Apparatus
5.1 Usual laboratory apparatus.
5.2 Electric sand bath or other heating device with the same effect: The
temperature (room temperature to 300°C) can be adjusted.
5.3 Ground Erlenmeyer flask: 200 mL.
5.4 Ground simple air condenser used with the ground Erlenmeyer flask: It is
about 1 cm in diameter and about 20 cm in length.
6 Analytical procedures
6.1 Preparation of sample
After the solid sample has been divided for several times, take about 100 g;
quickly grind it until it passes through a 0.50 mm aperture sieve (If the sample
is wet, it may pass through a 1.00 mm sieve). MIX well and place in a clean,
dry container. After shaking the liquid sample several times, quickly take about
100 mL and place it in a clean, dry container.
6.2 Preparation of sample solution
6.2.1 Solid sample: WEIGH 0.5 g~1 g (accurate to 0.0001 g) of sample in a 100
mL beaker; ADD a small amount of water; USE a glass rod to grind the solid to
dissolve it; TRANSFER the solution to a 100 mL volumetric flask; USE water to
dilute it and mix well.
6.2.2 Liquid sample: WEIGH 1 g~2 g (accurate to 0.0001 g) of sample and place
it in a 100 mL volumetric flask; USE water to dilute it and mix well.
6.3 Oxidation of sample solution
Immediately after mixing, pipette 5.0 mL of sample solution (homogeneous
emulsion) into a 200 mL ground Erlenmeyer flask; ADD 5.0 mL of potassium
dichromate solution (4.6) and 10.0 mL of sulfuric acid (4.3).
Connect the Erlenmeyer flask to the simple air condenser; PLACE it on an
electric sand bath that has been preheated to 200°C~230°C for heating. When
the first drop of condensate drops from the lower end of the simple air
condenser, the time is counted. Oxidize for 10 min±0.5 min. REMOVE the flask
and allow to cool. USE water to rinse the inner wall of the condenser; MAKE
the volume of the solution in the Erlenmeyer flask about 120 mL.
Note: If an oil bath and a hole-shaped electric heating device are used for oxidation, it shall
ensure that the heating glassware exposes at least 20 cm of the heat source and
funnel is covered.
6.4 Titration
ADD 3~5 drops of phenanthroline indicator (4.5) to the Erlenmeyer flask; USE
standard volumetric solution of ferrous sulfate (4.8) to titrate the remaining
potassium dichromate. The color changing process of the solution reaches the
end point through orange-yellow → blue-green → brown-red. If the volume
consumed by the titration is less than 1/3 of the volume consumed by titrating
the blank, it shall reduce the sample weighing quantity and re-determine.
6.5 Blank test
USE 5.0 mL of water instead of the sample solution. The other procedures are
the same as the determination of the sample solution. Only when the titration
absolute difference between two blank tests is ≤0.06 mL, the average can be
taken and substituted into the calculation formula.
7 Expression of analysis results
Organic matter content (w) is expressed by its mass fraction (%) and calculated
according to formula (2):
Where:
V1 - The volume of standard volumetric solution of ferrous sulfate consumed in
the determination of the blank, in milliliters (mL);
V2 - The volume of standard volumetric solution of ferrous sulfate consumed in
the determination of the sample, in milliliters (mL);
c - The concentration of standard volumetric solution of ferrous sulfate, in moles
per liter (mol/L);
D - Dilution multiple of sample solution during determination;
0.003 - Mass of carbon in grams equivalent to 1.00 mL of standard volumetric
solution of ferrous sulfate [c(FeSO4)=1.000 mol/L];
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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