SN/T 0736.10-2013Test method of import and export fertilizers. Part 10: Determination of free acid (English PDF)

Foreword

SN/T 0736 "Importers fertilizer test methods" is divided into 15 parts.

--- Part 1. sampling and sample preparation;

--- Part 2. Determination of moisture;

--- Part 3. Determination of particle size;

--- Part 4. Flame atomic absorption spectrometric method for the determination of sodium content;

--- Part 5. Determination of nitrogen content;

--- Part 6. Determination of phosphorus;

--- Part 7. Determination of potassium content;

--- Part 8. Determination of shrinkage diurea content;

--- Part 9. Determination of chlorine content;

--- Part 10. Determination of the free acid;

--- Part 11. automatic analyzer nitrogen content;

--- Part 12. Determination of Arsenic, chromium, cadmium, mercury, lead by inductively coupled plasma mass spectrometry;

--- Part 13. Flame atomic absorption spectrometric method for the determination of copper, zinc, iron, manganese, magnesium, cobalt, nickel content;

--- Part 14. Ion Chromatography Trace inorganic anions;

--- Part 15. microwave digestion - atomic fluorescence spectrometry determination of arsenic and mercury content.

This section SN/T Part of 100,736.

This section drafted in accordance with GB/T 1.1-2009 given rules.

The partial replacement of SN/T 0736.10-1999 "Importers fertilizer test methods - Determination of free acid." this section compares the SN/T 0736.10-1999, main technical changes are as follows.

--- This section according to GB/T 1.1 "Standardization Guide Part 1. Standard structure and writing rules" and GB/T 20001.4-2001 "Rules for drafting standards - Part 4. Chemical analysis methods," the provisions of the original SN/T 0736.10-Structure and preparation of 1999 were normative changes and additions;

--- This part of the method feeds, equipment, reagents, analytical procedure and precision has been modified.

This section proposed and managed by the National Certification and Accreditation Administration Committee.

1 Scope

SN/T 0736 provisions of this part of the determination of free acid content of the import and export of fertilizers.

This section applies to the determination of the free acid content of ammonium sulfate, ammonium nitrate, potassium sulfate, ammonium chloride, triple superphosphate fertilizer in import and export.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version suitable for use herein Member. For undated references, the latest edition (including any amendments) applies to this document.

Preparation of GB/T 601 chemical reagent standard titration solution GB/T 6379.2 measurement methods and results of Accuracy (trueness and precision) - Part 2. Determine the standard measurement method to repeat of the basic methods of reproduction Laboratory use specifications and test methods GB/T 6682 Analysis SN/T 0736.1 Importers fertilizer test methods - Part 1. Sampling and sample preparation

3 Reagents

Unless otherwise indicated, the reagents used were of analytical grade, laboratory water should be at least in line with GB/T 6682 in three water requirements.

3.1 sodium hydroxide.

3.2 citric acid monohydrate.

Disodium hydrogen phosphate 3.3 twelve.

3.4 volume fraction of 95% ethanol.

3.5 sodium hydroxide standard titration solution (0.1mol/L). according to GB/T 601 specified preparation and calibration.

3.6 citric acid standard solution (0.1mol/L). Weigh accurately 5.2525g of citric acid monohydrate (3.2) was dissolved in water, dilute to 250mL.

3.7 disodium hydrogen phosphate standard solution (0.1mol/L); accurately weighed 8.954g twelve - hydrated disodium hydrogen phosphate (3.3) is dissolved in water, the volume to 250mL.

3.8 buffer solution (pH value of about 4.5). Pipette 21.6mL standard solution of citric acid (3.6) and disodium hydrogen 28.4mL standard solution Internal solution (3.7) in the 100mL beaker, mix, add 0.5mL bromocresol green indicator (3.10).

3.9 methyl red indicator (1g/L). Weigh 0.1g methyl red, was dissolved in ethanol (3.4), diluted to 100mL with ethanol (3.4).

3.10 bromocresol green indicator (1g/L). Weigh 0.1g bromocresol green dissolved in ethanol (3.4), diluted to 100mL with ethanol (3.4).

4 Instrument

Analytical balance. a sense of the amount of 0.01g, 0.001g.

5 Sampling and sample preparation

Press SN/T 0736.1 predetermined sampling and sample preparation.