Patent Description:
The present invention relates to a method of analyzing calcium content in soil, the method comprising: a) obtaining a soil sample; b) adding a liquid to the soil sample to form a soil slurry; c) flowing the soil slurry through a filter to form a filtrate; d) blending a reagent composition with the filtrate to form a soil mixture; and e) flowing the soil mixture through an analysis tool along a flow direction whereby a calcium absorbance of the soil mixture is measured; and wherein the flow direction is oriented such that the soil mixture flows vertically.

Other embodiments of the present invention include a method of analyzing calcium content in soil, the method comprising: a) obtaining a soil sample; b) adding a liquid to the soil sample to form a soil slurry; c) flowing the soil slurry through a filter to form a filtrate; d) blending a reagent composition with the filtrate to form a soil mixture; and e) flowing the soil mixture through an analysis tool along a flow direction whereby a calcium absorbance of the soil mixture is measured; and wherein soil mixture comprises a surfactant and the flow direction is substantially horizontal and orthogonal to the direction of gravity.

Moreover, the features and benefits of the disclosure are illustrated by reference to the exemplified embodiments. Accordingly, the disclosure expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the disclosure being defined by the claims appended hereto.

The soil analysis of the present invention is performed to determine an elemental content of calcium in a soil sample.

According to an embodiment of the present disclosure, calcium may be tested according to the following methodology. A soil sample may be obtained and blended with liquid to create the soil slurry. The soil slurry may then flow through the filter element to create a filtrate, whereby one or more reagent may be added to the filtrate to create a mixture.

The soil mixture may then be analyzed for calcium content by absorbance that may be read via a spectrophotometer at a wavelength ranging from <NUM> to <NUM>. In some embodiments, the soil mixture may then be analyzed for calcium content by absorbance that may be read via a spectrophotometer at a wave length ranging from <NUM> to <NUM> - including all wavelengths and sub-ranges there-between - preferably about <NUM>.

In some embodiments, the calcium content analysis may occur inside of the analysis tool <NUM> and as the soil mixture flows along the vertical FD, whereby the vertical FD is substantially parallel to gravitational direction GD such that the soil mixture flows downward at least partially under the effects of gravity. In some embodiments, the calcium content analysis may occur inside of the analysis tool 110a and as the soil mixture flows along the vertical FD, whereby the vertical FD is substantially parallel to gravitational direction GD such that the soil mixture flows upward against the effects of gravity.

In alternative embodiments, the calcium content analysis may occur inside of the analysis tool <NUM> and as the soil mixture flows along the horizontal FD, whereby the horizontal FD is substantially orthogonal to the gravitational direction GD and the soil slurry flows horizontally through the analysis tool <NUM>.

According to embodiments of the calcium content analysis using the vertical FD and horizontal FD, the soil slurry may comprise a surfactant. It has been surprisingly discovered that the addition of a non-ionic surfactant provides an unexpected improvement in optical clarity that enhances the spectrophotometer calcium content analysis while ionic surfactants fail to provide such improved optical properties. Non-limiting examples of non-ionic surfactant include <NUM>-nonylphenyl polyethylene glycol, poly(ethylene glycol)(<NUM>) tridecylether, and mixtures thereof. The surfactant of this embodiment may be substantially free of ionic surfactant. The surfactant of this embodiment may be substantially free of anionic surfactant. The surfactant of this embodiment may be substantially free of cationic surfactant.

It has also bee surprisingly discovered that for the embodiments of the calcium content analysis that utilize a vertical FD, the soil slurry may also be substantially free of surfactant and still achieve the desire optical clarity while the same optical clarity is not achieved in the absence of such surfactants in the horizontal FD.

According to the embodiments directed to the calcium analysis, non-limiting examples of reagents include potassium hydrogen phthalate, chlorophosphonazo III, and combinations thereof.

The reagents may comprise a first reagent that includes potassium hydrogen phthalate at a concentration of about <NUM> to about <NUM> - including all concentrations and sub-ranges there-between. The reagents may comprise a second reagent that includes chlorophosphonazo III in a concentration of about <NUM> to about <NUM> per mL of water - including all concentrations and sub-ranges there-between.

The calcium analysis may further comprise the addition of an extractant, which may be blended with the soil slurry. Non-limiting examples of extractant include ammonium acetate. The extractant may comprise ammonium acetate in concentration ranging from about <NUM> to about <NUM> - including all concentrations and sub-ranges there-between.

According to this embodiment, the soil sample may be prepared by mixing the filtrate with the first reagent, subsequently mixing with the second reagent, and subsequently performing the absorbance reading.

According to this embodiment, the soil slurry and soil mixture may not be subjected to a centrifuge force before performing the calcium absorbance reading.

An experiment was performed to test the impact of horizontal FD and vertical FD as it relates to surfactant for a calcium soil analysis.

The samples of Examples <NUM>-<NUM> were prepared by blending soil and water together at a <NUM>:<NUM> ratio to create a slurry, whereby the slurry is pulled into the extraction portion of the system and potassium is extracted in a <NUM>:<NUM> ratio of slurry to extractant with ammonium acetate. After extraction, the extracted samples were filtered and the filtrate was subsequently blended with reagent to create a soil mixture, the reagent including potassium hydrogen phthalate and subsequently Chlorophosphonazo III. Each soil mixture of Examples <NUM>-<NUM> were then flowed along the horizontal FD through the analysis tool.

The sample of Example <NUM> included a non-ionic surfactant. The sample of Example <NUM> included an anionic surfactant. The sample of Example <NUM> included a cationic surfactant. The sample of Example <NUM> was free of surfactant.

The samples of Examples <NUM>-<NUM> were prepared by blending soil and water together at a <NUM>:<NUM> ratio to create a slurry, whereby the slurry is pulled into the extraction portion of the system and potassium is extracted in a <NUM>:<NUM> ratio of slurry to extractant with ammonium acetate. After extraction, the extracted samples were filtered and the filtrate was subsequently blended with reagent to create a soil mixture, the reagent including potassium hydrogen phthalate and subsequently Chlorophosphonazo III. Each soil mixture of Examples <NUM>-<NUM> were then flowed along the vertical FD through the analysis tool.

Each sample of Examples <NUM>-<NUM> were analyzed by the analysis tool at a wavelength of <NUM> to determine the calcium concentration in the sample. After mixing, each sample produces turbidity, and the ability to read through each sample was recorded as either a pass or fail - whereby the pass value equates to an optical property sufficiently clear to allow for the reading of the calcium concentration at a wavelength of <NUM> and the fail value equates to an optical property insufficiently clear to not allow for reading of the calcium concentration at a wavelength of <NUM>. The results are set forth below in Table <NUM>.

Claim 1:
A method of analyzing calcium content in soil, the method comprising:
a) obtaining a soil sample;
b) adding a liquid to the soil sample to form a soil slurry;
c) adding a surfactant to the soil slurry;
d) flowing the soil slurry through a filter to form a filtrate;
e) blending a reagent composition with the filtrate to form a soil mixture; and
f) flowing the soil mixture through an analysis tool along a flow direction that is substantially orthogonal to the direction of gravity, whereby a calcium absorbance of the soil mixture is measured.