Description:
TECHNICAL FIELD
My invention is directed to a test strips for the detection of heavy metals in aqueous solutions such as the detection of how much arsenic ,mercury lead and cadmium is present in the drinking water, juice, milk urine, saliva, dust, paint, food, etc at the home within a few minutes. The strip provides the specific determination of heavy metal; to the use of such strip ; and to the method for making such strip.
DESCRIPTION OF PRIOR ART
One invention discloses an ion indicating device which indicates the presence of ions in the effluent of ion exchange processes. The device comprises an ion-sensitive device made from resilient strip or sheet material and having secured to one side thereof a strip or sheet of active ion-exchange material. The device in its operation makes use of the volume change characteristics such as by swelling or shrinking, according to the nature of the ion the device has absorbed.
An object of the present invention, however, is to provide a simple paper strips and piece of copper as strip that will show a color change when detecting the presence of heavy metals in aqueous solutions.
For instance there are several silver-estimating test papers available that are used by photo processors to approximate the amount of silver in photographic recovery systems and to adjust the fixer replenisher rate to obtain maximum fixer efficiency. These test papers are efficient down to a concentration of 1000 ppm. (parts per million) silver in aqueous solutions. There is, however, a need for a test medium capable of detecting silver at about 0.5 ppm. Also, any test developed for

detecting such silver concentrate must be relatively simple and must employ instrumentation readily available to photo processors.
Another object of this invention, therefore, is to provide a test papers that will detect in aqueous solutions at least 0.5 ppm. (part per million), and preferably about 0.1 ppm., of the presence of heavy metals such as lead, mercury, cadmium and arsenic.
Still another object of the invention is to use a simple paper and piece of copper as strip an analytical device for determining the presence and the concentration of heavy metal in an aqueous solution.
A further object of the invention is to provide a method for making a simple paper strips and piece of copper as strip that will detect the presence of heavy metals in aqueous solutions.
A still further object of the invention is to provide a simple paper strips and piece of copper as strip, as made by the method, for detecting the presence of heavy metals in aqueous solutions.
Other objects of the invention will become apparent to those skilled in the art to which this invention pertains from the disclosure to follow.
DISCLOSURE OF INVENTION
The invention is directed to a simple paper and piece of copper as strip that becomes colored when detecting the presence of heavy metals in aqueous solutions, to a method of making a paper strips and copper strip for detecting heavy metals, to a strip as made by the method, and to the use of a strip which becomes colored when indicating the presence of heavy metals, the degree of

coloration being also a measurement of the concentration of such heavy metals in their oxide form.
Example -1
The method for arsenic detection includes 5x3 copper strip wash with water, now the strip is disperse in aqueous food ,such as milk juice water etc and heat for few minutes .
Black deposit onto the strip indicates the presence of arsenic.
Shining silver color spots indicates the presence of mercury
Example -2
Aqua's test sample put onto the strip and sprays with NAHC03 and 0.1% glysoniun
Violet color onto the strip indicates the presence of lead.
Example -3
The test strip is coated with the H2S, if the drop of test solution give yellow color, the presence of cadmium is confirm
The strips resulting from practice of this invention may serve as a field test kit for measuring; for instance, arsenic concentration in liquid food items. This strip, as tested, has been found capable of detecting as low as 0.1 part per million (ppm.) of heavy metals in a liquid food items. The strip undergoes a detectable color change when exposed to aqueous solutions containing heavy metals.

Some other heavy metals that may also be detected by the film include bismuth, copper, and gold.
The film is formed from a cellulose paper and copper piece by dissolving the first in a volatile solvent to form a liquid solution. The liquid solution is cast into a strip when using the strip in an aqueous solution containing a particular heavy metal; the strip gives specific color as a result of an ion exchange reaction between the coated chemical and the heavy metal.
There is a need, however, to be able to be much more efficient and more sensitive in detecting far lower concentrations of heavy metals in aqueous solutions, and especially, also, from the standpoint of ecological concerns before discharging such aqueous solutions. The practice of this invention, therefore, results in a significant improvement over these known heavy metal estimating kits, and as also previously mentioned herein, will be capable of detecting in aqueous solutions as low as 0.1 part per million (ppm.)

Claims:
1. The method of making a test strips for detecting heavy metals, comprising coatings of specific chemicals onto a cellulose ester in a volatile solvent to form a liquid solution, casting said liquid solution to form a film, test strips for the detection of heavy metals in aqueous solutions such as the detection of how much arsenic ,mercury lead and cadmium is present in the drinking water, juice, milk urine, saliva, dust, paint, food, etc at the home within a few minutes.
2. The method as defined in claim 1, wherein said cellulose strip is selected from the group consisting of cellulose acetate, cellulose butyrate, cellulose propionate and mixed esters thereof.
3. The method as defined in claim 1, wherein said coated chemical is selected from NAHCO3 and 0.1% glysoniun ,sodium sulfide, ammonium sulfide or potassium sulfide.
4.. In a method of detecting heavy metals in an aqueous solution wherein said aqueous solution contacts a strip for indicating the presence of said heavy metals, the said strip being transparent and becoming colored when indicating the presence of heavy metals, the extent of such coloration also indicating the measurement of concentration of such heavy metals.
5. The procedure as defined in claim 4 ,can be perform by housewife ,a layman person or any one and the strip will provides the specific determination of heavy metal; within few minutes.