NY/T 2272-2012Soil amendment - Measurement of calcium, magnesium, and silicon content (English PDF)

3.1 Atomic absorption spectrophotometric method (arbitration method)

3.1.1 Principle

As for calcium of the sample solution, in slightly acidic medium, USE a certain

amount of strontium salt as the release agent, to make it atomization in the

lean combustion air – acetylene flame; the generated atomic vapor absorbs

the characteristic wavelength 422.7 nm light which is emitted from the

calcium hollow cathode lamp, AND absorbance values is directly proportional

to the calcium ground state atomic concentration.

3.1.2 Reagents and materials

The preparation of the reagents, water and solution which are used in this

standard shall, unless otherwise indicated of specifications AND preparation

methods, be in accordance with the provisions of HG/T 2843.

It shall follow the provisions of 3.1.4.2.

3.2.4.3 Drawing of working curve

Respectively PIPETTE 0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 4.00 mL, AND 5.00

mL of calcium standard solution (3.2.2.1) into six 100 mL volumetric flasks;

USE water to make it reach to constant volume; MIX it uniformly. The

calcium's mass concentration of this standard series solution is respectively 0

µg/mL, 5.0 µg/mL, 10.0 µg/mL, 20.0 µg/mL, 40.0 µg/mL, AND 50.0 µg/mL.

Before measurement, based on the nature of the element to be measured

and the instrument performance, OPTIMIZE the measurement conditions of

argon flow rate, observation height, RF generator power, AND integration

time. Then USE the plasma emission spectrometer, at a wavelength of

317.933 nm, to measure the emission intensity of each standard solution.

USE the calcium's mass concentration of the standard series solution (µg/mL)

as the abscissa AND the corresponding emission intensity as the ordinate;

DRAW the working curve.

Note. It can, based on the different instrument sensitivities, ADJUST the mass

concentration of the standard series solution.

3.2.4.4 Measurement

USE the sample solution OR the solution which is diluted to certain ratio,

under the same conditions of the standard series solution for measurement

purposes, to measure the emission intensity of calcium; from the working

curve, FIND the corresponding mass concentration of the calcium (µg/mL).

3.2.4.5 Blank test

Except for not adding of sample, the rest steps are same as those described

in 3.2.4.4.

3.2.5 Analysis result presentation

It shall follow the provisions of 3.1.5.

3.2.6 Allowable difference

It shall follow the provisions of 3.1.6.

3.2.7 Conversion of mass concentration

It shall follow the provisions of 3.1.7.

4.1.4 Analysis procedures

4.1.4.1 Sample preparation

With respect to the solid samples, after multiple times of splitting, TAKE out

about 100 g of sample; rapidly GRIND it to the grain which can all pass the

0.50 mm pore size sieve (if the sample is wet, it shall pass through the 1.00

mm pore size sieve); MIX it uniformly; PLACE it in a clean AND dry container;

after the liquid sample is subject to multiple times of shaking, quickly TAKE

out about 100 mL; PLACE it in a clean AND dry container.

4.1.4.2 Sample solution preparation

- Solid sample. WEIGH 0.2 g ~ 3 g of sample (accurate to 0.0001 g);

PLACE into a 250 mL volumetric flask; ADD 150 mL of hydrochloric acid

solution (4.1.2.5) which was pre-heated to 28 °C ~ 30 °C; tightly PLUG

the volumetric flask; SHAKE the volumetric flask to disperse the sample

in the liquid; MAINTAIN the solution temperature at 28 °C ~ 30 °C; USE

the oscillator (4.1.3.2) the frequency of which is set to (180 ± 20) r/min

to oscillate it for 30 min; then TAKE the volumetric flask out; COOL it to

room temperature; USE water to dilute it to the mark; MIX it uniformly;

dry FILTER it; DISCARD the first few milliliters of filtrate; USE the rest

filtrate for measurement.

- Liquid sample. WEIGH 0.2 g ~ 3 g sample (accurate to 0.0001 g); PLACE

it into a 250 mL volumetric flask; USE water to make it reach to constant

volume; MIX it uniformly; dry FILTER it; DISCARD the first few milliliters

of filtrate; USE the rest filtrate for measurement.

4.1.4.3 Drawing of working curve

Respectively PIPETTE 0 mL, 1.00 mL, 2.00 mL, 4.00 mL, 8.00 mL, AND

10.00 mL of magnesium standard solution (4.1.2.4) into six 100 mL

volumetric flasks; respectively ADD 4 mL of hydrochloric acid solution

(4.1.2.1) AND 10 mL of strontium chloride solution (4.1.2.2); USE water to

make it reach to constant volume; MIX it uniformly. The magnesium's mass

concentration of this standard series solution is respectively 0 µg/mL, 1.00

µg/mL, 2.00 µg/mL, 4.00 µg/mL, 8.00 µg/mL, AND 10.00 µg/mL. Under the

selected optimum working conditions, at the wavelength of 285.2 nm, USE

the lean combustion air – acetylene flame; and USE the magnesium content

4.2.4.5 Blank test

Except for not adding of sample, the rest steps are same as the sample

solution measurement.

4.2.5 Analysis result presentation

It shall follow the provisions of 4.1.5.

4.2.6 Allowable difference

It shall follow the provisions of 4.1.6.

4.2.7 Conversion of mass concentration

It shall follow the provisions of 4.1.7.

5.1 Principle

The silicon in the sample solution is atomized and excited to a high energy

state in the ICP light source. The high energy state atom, when transited to

ground state, generates the electromagnetic radiation of characteristic

wavelength. AND the emission intensity is directly proportional to the silicon

atom concentration.

5.2 Reagents and materials

The preparation of the reagents, water and solution which are used in this

standard shall, unless otherwise indicated of specifications AND preparation

methods, be in accordance with the provisions of HG/T 2843.

5.2.1 Silicon standard solution. rho (Si) = 1000 µg/mL.

5.2.2 Hydrochloric acid solution. c (HCl) = 0.5 mol/L.

5.2.3 High purity argon.

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