Methods for analysis of soil samples

• US 20060088939A1
• Filed: 09/06/2005
• Published: 04/27/2006
• Est. Priority Date: 03/07/2003
• Status: Abandoned Application

• Current Assignee: Agresearch Limited
• Original Assignee: Agresearch Limited
• Inventors: Rajendram, Gordon Shanthakumar
• Application Number:
  US11/220,772
• Publication Number:
  US 20060088939A1
• Time in Patent Office: Days
• US Class Current: 436/31
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/3577 for analysing liquids, e.g. polluted water
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 33/24 Earth materials G01N33/42 takes precedence
• CPC Class Codes: Y10T 436/24 Nuclear magnetic resonance, electron spin resonance or other spin effects or mass spectrometry

Abstract

The present invention relates to methods for the preparation and analysis of soil samples to determine the presence, concentration and/or volume of at least one component in a soil sample, including preparation steps of extracting the component from the sample by use of aqueous solution and, depending on the element, adding a complexing agent to the aqueous solution and soil mixture. The resulting mixture is then able to be analysed via NIR or UV/Vis spectrometry as the component, not normally detectable via NIR or UV/Vis spectrometry, is converted into an accurately measurable form. The methods of the present invention may be used to obtain a test results on site and within a time period of 10 to 45 minutes rather than a time period of days using present methods.

Claims

1. A method for determining the presence, concentration and/or volume of at least one component in a soil sample, comprising:

a) adding at least one aqueous solution to a soil sample;

b) adding at least one complexing agent to the mixture of step (a); and

c) analysing the result of step (b) via NIR spectrometry;

wherein step (a) is completed within 10 minutes, and further wherein steps (a) and (b) prepare the sample in a manner that is suitable for NIR spectrometry.

19. The method of claim 1, wherein the complexing agent used in step (b) is selected from the group consisting of:

sodium tetraphenylborate (NaTPB), ammonium molybdate (Olsen P colouring agent), ascorbic acid, ethylene diamine tetra acetate (EDTA) or other known chelating agents, nitrilo-triacetic acid (NTA), DTPA, hydroxyl ethylenediamine triacetic acid (HEDTA), PDTA and EDDHA.

20. The method of claim 1, wherein steps (a) and (b) are completed at substantially the same time.

2. A method for determining the presence, concentration and/or volume of at least one component in a soil sample, comprising:

a) adding at least one aqueous solution to a soil sample;

b) adding at least one complexing agent to the mixture of step (a); and

c) analysing the result of step (b) via NIR spectrometry;

wherein step (a) is completed under pressure for a time period of 30 to 45 seconds, and further wherein steps (a) and (b) prepare the sample in a manner that is suitable for NIR spectrometry.

3. A method for determining the presence, concentration and/or volume of at least one component in a soil sample, comprising:

a) adding at least one aqueous solution to a soil sample;

b) adding at least one complexing agent to the mixture of step (a); and

c) analysing the result of step (b) via UV/Vis spectrometry;

wherein step (a) is completed within 10 minutes, and further wherein steps (a) and (b) prepare the sample in a manner that is suitable for UV/Vis spectrometry.

4. A method for determining the presence, concentration and/or volume of at least one component in a soil sample, comprising:

a) adding at least one aqueous solution to a soil sample;

b) adding at least one complexing agent to the mixture of step (a); and

c) analysing the result of step (b) via UV/Vis spectrometry;

wherein step (a) is completed under pressure for a time period of 30 to 45 seconds, and further wherein steps (a) and (b) prepare the sample in a manner that is suitable for UV/Vis spectrometry.

5. A method for determining the presence, concentration and/or volume of at least one component in a soil sample, comprising:

a) adding at least one aqueous solution to a soil sample;

b) adding at least one complexing agent to the mixture of step (a); and

c) analyzing the result of step (b) via NIR or UV/Vis spectrometry;

wherein step (a) is completed within 10 minutes or is completed under pressure for a time period of 30 to 45 seconds, and further wherein steps (a) and (b) prepare the sample in a manner that is suitable for NIR or UV/Vis spectrometry.

6. The method of claim 5, wherein the sample is field moist.

7. The method of claim 5, wherein the sample is at least in part dried.

8. The method of claim 5, wherein the component is an element.

9. The method of claim 8, wherein the elements tested are selected from the group consisting of:

phosphorus, sulphur, pH (hydrogen content), nitrogen, potassium (K), sodium (Na), calcium (Ca) and magnesium (Mg), and combinations thereof.

10. The method of claim 5, wherein an extra step is included between steps (a) and (b) of separating the liquid extract from the residual solids.

11. The method of claim 10, wherein separation methods include filtration or centrifugation.

12. The method of claim 5, wherein the soil samples are prepared for analysis in-situ whereby at least one aqueous solution of step (a) and/or at least one complexing agent of step (b) are applied directly to the sample area before the sample is removed from the ground.

13. The method of claim 5, wherein the aqueous solution used in step (a) is selected from the group consisting of:

sodium bicarbonate, sodium chloride, caesium chloride, water, dye solutions, and combinations thereof.

14. The method of claim 13, wherein the dye solutions are selected from resazurin and a universal pH indicator.

15. The method of claim 5, wherein the mixture from step (a) is decolourised.

16. The method of claim 15, wherein decolourising is completed by addition of 1 to 2 grams of charcoal which is then separated from the extract by filtration.

17. The method of claim 15, wherein decolourising is completed by passing the extract through a charcoal filter.

18. The method of claim 5, wherein the complexing agent is a binding or chelating compound which specifically binds to the component or components to be analysed.

21. The method for determining the presence, concentration and/or volume in a soil sample of properties selected from the group consisting of:

sulphur, carbon, pH, and combinations thereof, comprising;

a) adding at least one aqueous solution to a soil sample; and

b) analysing the result of step (a) via NIR spectrometry;

wherein step (a) is completed within 10 minutes, and further wherein step (a) prepares the sample in a manner suitable for NIR spectrometry.

22. A method for determining the presence, concentration and/or volume in a soil sample of properties selected from the group consisting of:

sulphur, carbon, pH, and combinations thereof, comprising;

a) adding at least one aqueous solution to a soil sample; and

b) analysing the result of step (a) via NIR spectrometry;

wherein step (a) is completed under pressure for a time period of 30 to 45 seconds, and further wherein step (a) prepares the sample in a manner suitable for NIR spectrometry.

23. A method for determining the presence, concentration and/or volume in a soil sample of properties selected from the group consisting of:

sulphur, carbon, pH, and combinations thereof, comprising;

a) adding at least one aqueous solution to a soil sample; and

b) analysing the result of step (a) via UV/Vis spectrometry;

wherein step (a) is completed within 10 minutes, and further wherein step (a) prepares the sample in a manner suitable for UV/Vis spectrometry.

24. A method for determining the presence, concentration and/or volume in a soil sample of properties selected from the group consisting of:

sulphur, carbon, pH, and combinations thereof, comprising;

a) adding at least one aqueous solution to a soil sample; and

b) analysing the result of step (a) via UV/Vis spectrometry;

wherein step (a) is completed under pressure for a time period of 30 to 45 seconds, and further wherein step (a) prepares the sample in a manner suitable for UV/Vis spectrometry.

25. A method for determining the concentration of potassium in a soil sample, comprising:

a) adding an aqueous solution of sodium bicarbonate to a soil sample;

b) adding sodium tetraphenylborate (NaTPB) to the mixture from step (a); and

c) analysing the result of step (b) via NIR spectrometry;

wherein step (a) is completed within 10 minutes, and further wherein steps (a) and (b) prepare the sample in a manner suitable for NIR spectrometry.

26. A method for determining the concentration of potassium in a soil sample, comprising:

a) adding an aqueous solution of sodium bicarbonate to a soil sample;

b) adding sodium tetraphenylborate (NaTPB) to the mixture from step (a); and

c) analysing the result of step (b) via NIR spectrometry;

wherein step (a) is completed under pressure for a time period of 30 to 45 seconds, and further wherein steps (a) and (b) prepare the sample in a manner suitable for NIR spectrometry.

27. A method for determining the concentration of Olsen P phosphorus in a soil sample, comprising:

a) adding an aqueous solution of sodium bicarbonate to a soil sample;

b) adding ammonium molybdate (Olsen P colouring agent) to the mixture from step (a) and degassing the sample; and

c) analysing the result of step (b) via NIR spectrometry;

wherein step (a) is completed within 10 minutes, and further wherein steps (a) and (b) prepare the sample in a manner suitable for NIR spectrometry.

28. A method for determining the concentration of Olsen P phosphorus in a soil sample, comprising:

a) adding an aqueous solution of sodium bicarbonate to a soil sample;

b) adding ammonium molybdate (Olsen P colouring agent) to the mixture from step (a) and degassing the sample; and

c) analysing the result of step (b) via NIR spectrometry;

wherein step (a) is completed under pressure for a time period of 30 to 45 seconds, and further wherein steps (a) and (b) prepare the sample in a manner suitable for NIR spectrometry.