FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICA TION
(See section 10, rule 13)
/. Title of the invention
A NANOPARTICLE DETECTION PROBE HAVING THERMOCHROMIC PROPERTIES
2. Applicant (s)
Name Nationality Address
TATA CHEMICALS LTD. INDIA BOMBAY HOUSE, 24 HOM1 MODI STREET,
MUMBA I-400001
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it is
i
to be performed.

The disclosure relates to a probe for detecting nanoparticles. The disclosure also relates to a kit for detecting nanoparticles. The disclosure further relates to a process for detecting nanoparticles.
BACKGROUND
Nanoparticles are becoming increasingly important in today's world. Application of nanoparticles ranges from solid state physics to biology. For example silver nanoparticles are used as antimicrobial agents, titanium dioxide nanoparticles are used in sunscreens, cosmetics and in coatings.
Because of their size, nanoparticles are not easy to detect, and there is a need for methods that would allow for the detection of nanoparticles. In public health, for example, there is concern about the impact caused by the accelerating rate of nanoparticle emissions and waste. Methods currently used for detection of nanoparticles includes optical chromophore counting, resonant light scattering and Raman scattering techniques, as well as the use of microscope techniques such as Scanning Transmission Electron Microscopy (STEM), or High Resolution Transmission Electron Microscopy (HRTEM). Most methods currently present for the detection of nanoparticles are complicated and require complex devices. This makes such detection methods expensive and difficult to use.
Therefore there is a need for a nanoparticle detection probe and a method that allows for the detection of nanoparticles in a simple manner without the use of expensive devices.
SUMMARY
The disclosure relates to a nanoparticle detection probe. The nanoparticle detection probe has thermochromic properties over a known transition temperature range, the probe includes a transition metal derivative of saturated anacardic acid or anacardic acid enes or both in an organic solvent, the transition metal derivative being a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid

enes or a 2:1 derivative having two molecules of saturated anacardic acid or anacardic acid enes bonded with one transition metal ion. The detection of nanoparticles by the probe is indicated by a change in the transition temperature range of the probe. The disclosure also relates to a kit for detecting nanoparticles in a medium. The kit includes a nanoparticle detection probe having thermochromic properties over a known transition temperature range.The probe comprises a transition metal derivative of saturated anacardic acid or anacardic acid enes or both for dissolution in an organic solvent, the transition metal derivative being a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of saturated anacardic acid or anacardic acid enes bonded with one transition metal ion; and a set of instructions. The instructions includ steps for detecting the presence of nanoparticles in the medium, wherein detection of nanoparticles by the probe in the medium is indicated by a change in the transition temperature range of the probe.
The disclosure also relates to a process for detecting nanoparticles in a medium. The process includes adding a transition metal derivative of anacardic acid or anacardic acid enes or both to the medium in the presence of an organic solvent, the transition metal derivative having thermochromic properties over a known transition temperature range and being a 1:1 derivative having one transition metal ion bonded with one molecule of anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of anacardic acid or anacardic acid enes bonded with one transition metal ion; heating the mixture till thermochromic properties are observed. The detection of nanoparticles is indicated by a change in the transition temperature range of the transition metal derivative of anacardic acid or anacardic acid enes or both.

DETAILED DESCRIPTION
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
A nanoparticle detection probe is disclosed. The nanoparticle detection probe comprises of a transition metal derivative of saturated anacardic acid or anacardic acid enes or both having thermochromic properties over a known transition temperature range in an organic solvent, wherein the detection of nanoparticles by the probe is indicated by a change in the transition temperature range of the probe. The transition metal derivative of saturated anacardic acid or anacardic acid enes or both may be a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes. The transition metal derivative of saturated anacardic acid or anacardic acid enes or both may also be a 2:1 derivative having one transition metal ion bonded with two molecules of saturated anacardic acid or anacardic acid enes.
In accordance with an aspect, the nanoparticle detection probe comprises of a transition metal derivative of saturated anacardic acid or anacardic acid enes or both and saturated anacardic acid or anacardic acid enes such that the ratio of saturated anacardic acid or anacardic acid enes or both to the transition metal is in the range of 2:1 to 10:1, having

thermochromic properties over a known transition temperature range in an organic solvent, wherein the detection of nanoparticles by the probe is indicated by a change in the transition temperature range of the probe.
Saturated anacardic acid is a molecule having a salicylic acid unit linked to a saturated linear alkyl chain (R). The alkyl chain may have any number of carbon atoms, depending upon the source of the saturated anacardic acid. By way of an example, in the saturated anacardic acid obtained from cashew nut shell, the alkyl chain (R) is a saturated 15-carbon long alkyl chain represented as 1R below. The molecular structure of the saturated anacardic acid obtained from cashew nut shell liquid is illustrated below:

Anacardic acid enes are unsaturated anacardic acids having various degrees of unsaturation in the side chain. In accordance with aspect, the anacardic acid enes obtained from cashew nut shell liquid have 1 to 3 double bonds. The anacardic acid enes obtained from cashew nut shell liquid may be an 8'Z -monoene (2R); 8'Z, 1 l'Z-diene(3R) and 8'Z, 11 'Z, 14'-triene (4R) anacardic acid enes having the following molecular structures:

The 1:1 transition metal derivative of saturated anacardic acid or anacardic acid enes has one transition metal ion (M) bonded with one molecule of the saturated anacardic acid or

inacardic acid enes. The molecular structure of the 1:1 transition metal derivative of saturated macardic acid or anacardic acid enes is illustrated below:

R may be a saturated or an unsaturated side chain. By way of an example the alkyl Chain (R) is saturated 15-carbon long alkyl chain represented as 1R above or unsaturated 15-carbon long chain having 1 to 3 double bonds represented as 2R, 3R and 4R above.
In the 2:1 transition metal derivative of saturated anacardic acid or anacardic acid enes, one transition metal ion (M) is bonded with two molecules of saturated anacardic acid or anacardic acid enes. The molecular structure of the 2:1 derivative saturated of anacardic acid or anacardic acid enes is illustrated below:

R may be a saturated or an unsaturated side chain. By way of an example the alkyl chain (R) is saturated 15-carbon long alkyl chain represented as 1R above or unsaturated 15-carbon long chain having 1 to 3 double bonds represented as 2R, 3R and 4R above.

In accordance with an aspect, the transition metal derivative of saturated anacardic acid or anacardic acid enes or both may be any transition metal derivative. In accordance with an aspect the transition metal derivative of saturated anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron, cobalt or copper.
In accordance with an aspect, the transition metal derivative of anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron or cobalt. In accordance with an aspect 2:1 transition metal derivative of anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron, cobalt or copper.
In accordance with an aspect the organic solvent may be any organic solvent including but not limited to aromatic hydrocarbon solvent, aliphatic hydrocarbon solvent, chlorinated solvent, carboxylic esters or hydroxylated solvents.
A kit for detecting nanoparticles in a medium is also disclosed. The kit comprises of a nanoparticle detection probe and a set of instructions that includes the steps for detecting the presence of nanoparticles in the medium. The nanoparticle detection probe comprises of a transition metal derivative of saturated anacardic acid or anacardic acid enes or both for dissolution in an organic solvent. The probe may be a 1:1 derivative of saturated anacardic acid or anacardic acid enes or both having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes or a 2:1 derivative of saturated anacardic acid or anacardic acid enes or both having one transition metal ion bonded with two molecules of saturated anacardic acid or anacardic acid enes. The probe has thermochromic properties over a known transition temperature range. The detection of nanoparticles in a medium by the probe is indicated by a change in the transition temperature range of the probe.
The set of instructions in the kit include steps for detecting the presence of nanoparticles in the medium. The instructions may include additional details such as a list of

solvents that may be used to dissolve the transition metal derivate of saturated anacardic acid or anacardic acid enes or both and the corresponding transition temperature range at which the probe exhibits thermochromic properties when dissolved in the solvent.
A process for detecting nanoparticles in a medium is also disclosed. The process comprises of adding a transition metal derivative of anacardic acid or anacardic acid enes or both to the medium in the presence of an organic solvent. The transition metal derivative of saturated anacardic acid or anacardic acid enes or both have thermochromic properties over a known transition temperature range. The medium and the transition metal derivative of anacardic acid or anacardic acid enes or both in the presence of the organic solvent are mixed and heated till thermochromic properties are observed. The detection of nanoparticles in the medium is indicated by a change in the transition temperature range of the transition metal derivative of saturated anacardic acid or anacardic acid enes or both.
In accordance with an aspect, the medium may be in a solid form. The medium in the solid form may be suspended in an organic solvent. To the medium in organic solvent solid metal derivative of anacardic acid or anacardic acid enes or their mixture may be added. Alternatively, a solution of metal derivative of saturated anacardic acid or anacardic acid enes or their mixture in the organic solvent may be added to the medium in the organic solvent. The mixture is then heated till the thermochromic properties are observed.
Alternatively, the medium may be dispersed in water to obtain an aqueous solution of the medium. The aqueous solution of the medium and the solution of metal derivative of saturated anacardic acid or anacardic acid enes or both in organic solvent are mixed to obtain a reaction mixture having an organic phase including the transition metal derivative of saturated anacardic acid or anacardic acid enes or both and an aqueous phase with the dispersed medium. The reaction mixture is heated till thermochromic properties are observed in the organic phase.

In accordance with an aspect, the heating of the reaction mixture to observe the thermochromic property is carried out in stages. The temperature of the reaction medium is increased to a predetermined higher temperature and then maintained at a higher temperature for a predetermined period of time. By way of a specific example the temperature of the reaction mixture is increased by 5°C and then maintained at the higher temperature for upto 5 min.
The presence of nanoparticles in the medium is indicated by change in the transition temperature of the transition metal derivative of saturated anacardic acid or anacardic acid enes or both. The thermochromic properties of the transition metal derivative of saturated anacardic acid or anacardic acid enes or both may for example be observed at temperatures lower than the known temperatures if nanoparticles are present the medium. The detection of nanoparticles may also be indicated by an increase in the transition temperature of the saturated anacardic acid or anacardic acid enes or both with the presence of nanoparticles in the medium.
In accordance with an aspect, the process may further comprise of determining the transition temperature range of the metal derivative of saturated anacardic acid or anacardic acid enes or both comprising of dissolving the metal derivative of saturated anacardic acid or anacardic acid enes or both in an organic solvent and heating the solution till the thermochromic properties are observed.
A process for production of the nanoparticle detection probe is also disclosed. The process includes reacting an anacardic acid feed including saturated anacardic acid or anacardic acid enes or both with a transition metal to obtain transition metal derivative of saturated anacardic acid or anacardic acid enes or both, the transition metal derivative thus obtained having reversible thermochromic properties. The transition metal derivative of saturated anacardic acid or anacardic acid enes obtained may be a 1:1 transition metal

derivative of saturated anacardic acid or anacardic acid enes or both or a 2:1 transition metal derivative of saturated anacardic acid or anacardic acid enes or both.
In accordance with an aspect, the process for the production of the nanoparticle detection probe comprises reacting the anacardic acid feed including saturated anacardic acid or anacardic acid enes or both with an alkali metal hydroxide to obtain an alkali metal derivative of saturated anacardic acid or anacardic acid enes or both. A transition metal salt is added to the alkali metal derivative of saturated anacardic acid or anacardic acid enes or both to precipitate the transition metal derivative of saturated anacardic acid or anacardic acid enes or both, the transition metal derivative thus obtained having reversible thermochromic properties.
In accordance with an aspect, a pre-calculated amount of alkali metal hydroxide is reacted with the anacardic acid feed to obtain mono-alkali metal derivative or di-alkali metal derivative of saturated anacardic acid or anacardic acid enes or both.
In accordance with an aspect, one mole of alkali metal hydroxide is reacted with one mole of saturated anacardic acid or anacardic acid enes or both to obtain a mono-alkali metal derivative of saturated anacardic acid or anacardic acid enes or both. The transition metal salt is added to the mono-alkali metal derivative of saturated anacardic acid or anacardic acid enes or both thus obtained, to precipitate the 2:1 transition metal derivative of saturated anacardic acid or anacardic acid enes or both.
In accordance with an aspect, two mole of alkali metal hydroxide is reacted with one mole of saturated anacardic acid or anacardic acid enes or both to obtain the di-alkali metal derivative of saturated anacardic acid or anacardic acid enes or both. The transition metal salt is added to the di-alkali metal derivative of saturated anacardic acid or anacardic acid thus obtained, to precipitate the 1:1 transition metal derivative of saturated anacardic acid or anacardic acid enes or both.

The precipitated transition metal derivative of saturated anacardic acid or anacardic acid enes or both are separated and dried. The precipitated transition metal derivative of saturated anacardic acid or anacardic acid enes or both may be separated by any means including but not limited to filtration, decantation or centrifugation.
In accordance with an embodiment, the process further comprises adding saturated anacardic acid or anacardic acid enes or both to the transition metal derivative of saturated anacardic acid or anacardic acid enes or both such that the ratio of saturated anacardic acid or anacardic acid enes to metal is in the range of 2:1 to 10:1.
Solid saturated anacardic acid or anacardic acid enes or both may be added to the precipitated transition metal derivative of saturated anacardic acid or anacardic acid enes or both to obtain the reversible thermochromic additive. Alternatively, transition metal derivative of saturated anacardic acid or anacardic acid enes or both may be dissolved in an organic solvent and saturated anacardic acid or anacardic acid enes or both added to the solution such that the ratio of saturated anacardic acid or anacardic acid enes to metal is in the range of 2:1 to 10:1. In accordance with an aspect, solid saturated anacardic acid or anacardic acid enes or both is added to the solution of transition metal derivative of saturated anacardic acid or anacardic acid enes.
The alkali metal hydroxide used is a hydroxide of alkali metal including from the group comprising sodium, lithium, potassium, rubidium, caesium or francium. The transition metal salt is a divalent metal salt including but not limited to halides, nitrates, sulfates, phosphates or carboxylate salts of transition metals including but not limited to iron, copper or cobalt.
In accordance with an alternate embodiment, the process for the production of the nanoparticle detection probe comprises of preparing a solution of anacardic acid feed including saturated anacardic acid or anacardic acid enes or both in an organic solvent and

preparing an aqueous solution of an organic metal salt. The solution of saturated anacardic acid or anacardic acid enes or both and the aqueous solution of the organic metal salt are mixed to obtain a reaction mixture having an organic phase and an aqueous phase. The reaction mixture is held for a predetermined period of time till the transition metal derivative of saturated anacardic acid or anacardic acid enes or both are formed in the organic phase. The formation of transition metal derivative of saturated anacardic acid or anacardic acid enes or both in the organic phase is indicated by the appearance of colour in the organic phase.
The organic phase is then separated from the aqueous phase to obtain the transition metal derivative of saturated anacardic acid or anacardic acid enes or both, the transition metal derivative being thus obtained is a 1:1 derivative or a 2:1 derivative having reversible thermochromic properties over a known temperature range.
In accordance with an aspect, the organic phase may be separated from the aqueous phase by any known method including but not limited to decantation or phase separation.
In accordance with an embodiment, the process further comprises of recovering solid transition metal derivative of saturated anacardic acid anacardic acid enes or both from the separated organic phase by first evaporating the solvent from the separated organic layer and then drying the solid thus obtained.
In accordance with an embodiment, the process further comprises adding saturated anacardic acid or anacardic acid enes or both to the organic phase containing the transition metal derivative of saturated anacardic acid or anacardic acid enes or both such that the ratio of saturated anacardic acid or anacardic acid enes or both to the transition metal is in the range of 2:1 to 10:1. In accordance with an aspect the saturated anacardic acid or anacardic acid enes added to the organic phase containing the transition metal derivative of saturated anacardic acid or anacardic acid enes of both is in solid form.

In accordance with an aspect, the organic metal salt used is a metal carboxylate. The organic solvent used is selected from the group comprising aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, chlorinated solvents, carboxylic esters and hydroxylated solvents.
In accordance with an aspect, anacardic acid feed includes but is not limited to, cashew nut shell liquid (CNSL) containing a mixture of saturated anacardic acid and anacardic acid enes, anacardic acid enes or a mixture of anacardic acid enes obtained from cashew nut shell liquid, or saturated anacardic acid obtained by saturation of anacardic acid enes obtained from cashew nut shell liquid.
Specific embodiments are disclosed below:
A nanoparticle detection comprising a transition metal derivative of saturated anacardic acid or anacardic acid enes or both in an organic solvent the probe having tbermochromic properties over a known transition temperature range, the transition metal derivative being a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of saturated anacardic acid or anacardic acid enes bonded with one transition metal ion, wherein detection of nanoparticles by the probe is indicated by a change in the transition temperature range of the probe.
A kit for detecting nanoparticles in a medium comprising a nanoparticle detection probe having thermochromic properties over a known transition temperature range, the probe comprising a transition metal derivative of saturated anacardic acid or anacardic acid enes or both for dissolution in an organic solvent, the transition metal derivative being a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of saturated anacardic acid or anacardic acid enes bonded with one transition metal ion; and a set of instructions

including steps for detecting the presence of nanoparticles in the medium, wherein detection
of nanoparticles by the probe in the medium is indicated by a change in the transition
temperature range of the probe.
Such nanoparticle detection probe(s), wherein the nanoparticle detection probe comprises of a
transition metal derivative of saturated anacardic acid or anacardic acid enes or both and,
saturated anacardic acid or anacardic acid enes such that the ratio of saturated anacardic acid
or anacardic acid enes or both to the transition metal is in the range of 2:1 to 10:1.
Such nanoparticle detection probe(s), wherein the organic solvent is any one of aromatic
hydrocarbon solvents, aliphatic hydrocarbon solvents, chlorinated solvents, carboxylic esters
or hydroxylated solvent.
Such nanoparticle detection probe(s), wherein the }:1 transition metal derivative of anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron or cobalt.
Such nanoparticle detection probe(s), wherein the 2:1 transition metal derivative of anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron, cobalt or copper.
Such nanoparticle detection probe(s), wherein the molar concentration of anacardic acid or anacardic acid enes or both in the organic solvent is at least 10-2 moles.
Further specific embodiments are disclosed below:
A process for detecting nanoparticles in a medium comprising adding a transition metal derivative of anacardic acid or anacardic acid enes or both, to the medium in the presence of an organic solvent, , the transition metal derivative having thermochromic properties over a known transition temperature range and being a 1:1 derivative having one transition metal ion bonded with one molecule of anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of anacardic acid or anacardic acid enes bonded with

one transition metal ion; and mixing the solution and the medium followed by heating till thermochromic properties are observed; wherein detection of nanoparticles is indicated by a change in the transition temperature range of the transition metal derivative of anacardic acid or anacardic acid enes or both.
Such process(s), wherein the transition metal derivative of anacardic acid or anacardic acid enes or both is a derivative of any one of copper, iron or cobalt.
Such process(s), wherein the medium is a solid.
Such process(s), wherein the medium is dispersed in an organic solvent.
Such process(s) wherein the medium is dispersed in water.
Such process(s), wherein the thermochromic properties are observed in the organic phase including the transition metal derivative of anacardic acid or anacardic acid enes or both.
Such process(s), wherein the organic solvent is any one of aromatic hydrocarbon solvent, aliphatic hydrocarbon solvents, chlorinated solvents, carboxylic esters or hydroxylated solvent.
Such process(s), wherein heating is carried out in stages, including increasing the temperature to a predetermined higher temperature and maintaining the higher temperature for a predetermined period of time.
The following examples are provided to explain and illustrate certain preferred embodiments of the process of the invention.
Example 1: Thermochromism in presence of metal nanoparticles; biphasic interaction:
The metal nanoparticles were obtained by the wet chemical reduction method using borohydride as the reducing agent. The resulting metal nanoparticles (e.g., gold, silver, copper) were then made to disperse in water by use of suitable capping agent and/or a

stabilizer. The metal nanoparticles in aqueous phase were made to share a boundary with the thermochromic anacardic acid copper derivatives and both these solutions were taken in a double jacketed condenser. Water was circulated through the external jacket and the solutions were gradually but uniformly heated. The increase in temperature of the upper organic layer was constantly monitored using a thermometer while carefully checking the color change. The green colour of the upper organic layer deepened and then changed. Specifically the colour changed from green to brown at 80°C. Using 10- 4 M concentration of gold solution (average particle size 8 nm) in the aqueous phase, a temperature difference of 17 °C was observed for the difference in the thermochromic transition temperature. Reversibility of the color change was observed by cooling the solution below 50 °C.
Example 2: Effect of Metal Nanoparticles in a Single Phase.
Gold nanoparticles in the size range of 8-10 nm in a concentration of 10"4 molar was completely phase transferred into o-xylene by use of a phase transfer agent. A 10 ml of this solution was placed in a test tube and to this anacardic acid metal derivative in o-xylene was added in such a way that the concentration of the derivative in the final solution was 10-2 M. The test tube was inserted in a water bath and the heating done with constant monitoring of the increase in temperature with concomitant color changes. The change in the thermochromic transition temperature was measured carefully and the temperature difference was found to be of a similar magnitude (17 °C). Reversibility of the color changes was observed many times without change in the forward and reverse thermochromic transition temperatures. Similar experiments were performed with silver nanoparticles (average particle size of 30 nm) but the temperature variance was around 8 °C. The reversibility in color change was clearly observed in both cases.

Example 3: Effect of heating the metal nanoparticle solution through thermal and radiative heating.
Solution of gold organosol in xylene was taken in a flask. To this, anacardic acid copper derivative was added in xylene in such a way that the final concentrations of gold and anacardic acid copper derivatives were \0-4 and 10" molar respectively. The green coloration of resulting solutions was identical to that of the pure copper anacardic acid derivative in solution. As an alternative, gold concentration was further reduced to 10-5 M. The solutions were heated by both thermal and radiative heating. Surprisingly, under both conditions the transition in color occurred about 17 °C below its normal transition temperatures. Upon cooling, both exhibited reversible color changing phenomenon.
Example 4; Thermochiromic behavior with metal oxide nanoparticles
Anacardic acid copper derivative in xylene was taken in a flask. To this, zinc oxide nanoparticles capable of dispersing in aqueous, organic and bare nanoparticle powders were added in small amounts. The samples containing pure anacardic acid copper derivative, added by zinc oxide nanopowder, zinc oxide organosol and zinc oxide hydrosol dispersed in solution were all heated in a hot water bath gradually. In certain instances small amount of a blue copper metal salt precipitated while the color of the solution is largely green. The small change in coloration was due to anacardic acid picking small amount of divalent zinc which could also form divalent metal complexes having less starker coloration. The flasks containing zinc oxide nanoparticles in different forms underwent color change at reasonably lower temperatures (about 15 °C) than the one containing pure anacardic acid copper derivative. This clearly indicated that the thermochromism is not only restricted to metal nanoparticles but to metal oxide nanoparticles as well. Similar results were obtained in experiments performed on the commercial titanium dioxide nanoparticles.

Example No. 5: Thermochromism temperature variance with particle size:
Anacardic acid metal derivative in 10"2 Molar concentration (10 ml) was added by titanium dioxide of two different sizes. The average particle sizes of these two particles were in the range of 25 nm (Degussa P25) and 7 nm respectively. It was noticed that the thermochromic temperature variance was higher in the solution suspended with smaller particle sizes (about 15 °C) while the solution containing bigger particulates had a smaller deviation from the thermochromic transition temperature (about 7 °C). The results corroborate well with the results from the experiments performed on different metal nanoparticles of different sizes (example numbers. 1 and 2).
INDUSTRIAL APPLICABILITY
The nanoparticle probe as described above allows for the detection of nanoparticles in a simple manner. The process using the described probe is simple, easy to carry out and does not require complicated instrumentation. Therefore, the detection of nanoparticles using the probe may even be carried out by a person without any technical knowledge allowing for its versatile use in a number of applications.

WE CLAIM:
I. A nanoparticle detection probe comprising:
a transition metal derivative of saturated anacardic acid or anacardic acid enes or both in an organic solvent, the probe having thermochromic properties over a known transition temperature range, the transition metal derivative being a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of saturated anacardic acid or anacardic acid enes bonded with one transition metal ion, wherein detection of nanoparticles by the probe is indicated by a change in the transition temperature range of the probe.
2. A kit for detecting nanoparticles in a medium comprising:-
a nanoparticle detection probe having thermochromic properties over a known transition temperature range, the probe comprising a transition metal derivative of saturated anacardic acid or anacardic acid enes or both for dissolution in an organic solvent, the transition metal derivative being a 1:1 derivative having one transition metal ion bonded with one molecule of saturated anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of saturated anacardic acid or anacardic acid enes bonded with one transition metal ion; and
a set of instructions including steps for detecting the presence of nanoparticles in the medium, wherein detection of nanoparticles by the probe in the medium is indicated by a change in the transition temperature range of the probe.

3. A nanoparticle detection probe as claimed in claim 1 or 2, wherein the nanoparticle detection probe comprises of a transition metal derivative of saturated anacardic acid or anacardic acid enes or both and, saturated anacardic acid or anacardic acid enes such that the ratio of saturated anacardic acid or anacardic acid enes or both to the transition metal is in the range of 2:1 to 10:1.
4. A nanoparticle detection probe as claimed in claim 1 or 2, wherein the organic solvent is any one of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, chlorinated solvents, carboxylic esters or hydroxylated solvent.
5. A nanoparticle detection probe as claimed in claim 1 or 2, wherein the 1:1 transition metal derivative of anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron or cobalt.
6. A nanoparticle detection probe as claimed in claim 1 or 2, wherein the 2:1 transition metal derivative of anacardic acid or anacardic acid enes or both is a transition metal derivative of any one of iron, cobalt or copper.
7. A nanoparticle detection probe as claimed in claim 1 or 2, wherein the molar concentration of anacardic acid or anacardic acid enes or both in the organic solvent is at least 10" moles.
8. A process for detecting nanoparticles in a medium comprising:
adding a transition metal derivative of anacardic acid or anacardic acid enes or both to the medium in the presence of an organic solvent, , the transition metal

derivative having thermochromic properties over a known transition temperature range and being a 1:1 derivative having one transition metal ion bonded with one molecule of anacardic acid or anacardic acid enes or a 2:1 derivative having two molecules of anacardic acid or anacardic acid enes bonded with one transition metal ion; and
heating the mixture till thermochromic properties are observed; wherein detection of nanoparticles is indicated by a change in the transition temperature range of the transition metal derivative of anacardic acid or anacardic acid enes or both.
9. A process as claimed in claim 8, wherein the transition metal derivative of anacardic acid or anacardic acid enes or both is a derivative of any one of copper, iron or cobalt.
10. A process as claimed in claim 8, wherein the medium is a solid.
11. A process as claimed in claim 8, wherein the medium is dispersed in an organic
solvent.
12. A process as claimed in claim 8, wherein the medium is dispersed in water.
13. A process as claimed in claim 12, wherein the thermochromic properties are observed in the organic phase including the transition metal derivative of anacardic acid or anacardic acid enes or both.

14. A process as claimed in claim 8, wherein the organic solvent is any one of aromatic hydrocarbon solvent, aliphatic hydrocarbon solvents, chlorinated solvents, carboxylic esters or hydroxylated solvent.
15. A process as claimed in claim 8, wherein heating is carried out in stages, including increasing the temperature to a predetermined higher temperature and maintaining the higher temperature for a predetermined period of time.
16. A nanoparticle detection probe substantially as herein described.
17. A kit for detecting nanoparticles in a medium substantially as herein described.
18. A process for detecting nanoparticles in a medium substantially as herein described.