Claims:A portable device, comprising:

 Miniaturized instrumentation capable of making highly sensitive amperometric measurements.
 Our design supports the democratization of research by providing a minimalistic, yet versatile solution for applications where miniaturization is a priority, such as wearable sensors and handheld diagnostic devices.
 Employing Digital to Analog Converter (12 bit single channel DAC) to enhance the selectivity, sensitivity and specificity of current measurement. (Detection level: 4.5 nA).
, Description:6. Background of the invention
Water contamination is one of the most serious hazards to not only the human species, but also too many other living things on the earth. Water contamination has increases rapidly in the 21st century, due to increasing industrialization. Since the last several decades, determining hazardous compounds from contaminated water has been one of the most difficult tasks for scientists and researchers all over the world.
Heavy metal ions (HMIs) are one of several contaminants that pose a serious hazard to living beings. In order to safeguard and sustain the ecological system, researchers are particularly interested in the elimination of HMIs.
Because of their outstanding optical, electrical, and catalytic characteristics due to quantum size effects, nanomaterials have been widely researched in optical and electrochemical sensors for analytical equipment. When compared to conventional and traditional organic probes, nanomaterials are more effective and may be used for trace detection, complex sample analysis, and multicomponent experiments.
Due to device size limitations, simple-to-use, low-cost, and portable detection systems generally have lower sensitivity and selectivity. The use of nano probes can compensate the shortage of a portable device and shows a good sensitivity and selectivity.
As a result, miniaturized and portable electrochemical instruments are more effective and sorely needed for on-site detection of HMIs. In the worldwide context, the commercial availability of portable electrochemical devices for heavy metal detection is quite limited.
Despite the fact that just a few patents have been granted, the gadgets are not yet accessible on the market. Various analytical equipment, including atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICPMS), mass spectroscopy (MS), and X-ray fluorescence spectroscopy (XPS), have been employed to identify HMIs in the water system to date.
However, due to several key limitations such as high costs, lack of mobility, time consuming for sample preparation/pre-treatment, and the requirement of highly experienced operators, the above-mentioned equipment is finding it difficult to identify HMIs.
In India, there are few number of researchers who have attempted to develop devices for many different applications such as detection of fertilizers in wastewater and device for detection of mycotoxin. However, in our knowledge, there are no researchers who are involved in our country in the development of miniaturized and portable electrochemical devices for the detection of heavy metal ions in the wastewater. Thus the proposed portable device is simple to use, uses less energy, has a high sensitivity, is economical, Easy fabrication, can do in-situ and on-the-spot analysis, and is portable, miniaturized, and highly integrated.

7. Complete descriptions of the invention
A novel integrated circuit (IC) three sensory electrode system with built in trance impedance amplifier circuit integrated in a single chip is used for onsite and in-situ detection of several heavy metals at the same time it operates on the principal of square wave voltammetry (SWV) method. Direct digital frequency synthesizer (DDFS) was exploited in the circuit design to generate a linear and very low frequency scanning waveform for SWV. An ultra-low bias current, a high performance operational amplifier, a lock-in amplifier, and several noise reduction methods, such as cable selection, PCB cleaning, and guarding, were utilized to achieve the capability of ultra-low current measurement.

BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiments of the invention are described here by way of example with reference to the attached drawings, wherein
Fig 1 Potentiostat portable device
1a) Lower half of casing
1b) Board 1 assembled with lower half
1c) Screws and spacers (4 Nos.) assembled
1d) Insulating pad added underneath Board 2
1e) Top board assembled
1f) Upper half assembled and screws tightened
1g) Potentiostat portable device.
Fig. 2 illustrates top view of a Potentiostat portable analysis device
Fig. 3 illustrates cross - sectional view of a Potentiostat portable analysis device
Fig. 4 shows the total functional topology of HMIs.
Fig. 5 Schematic Representation of LMP 91000
Fig 6 is a Block Diagram of Digital Analog Converter (DAC)
Fig 7 is a functional Block Diagram of 16 bit 4 Channel Analog to digital Converter (ADS 1115).
Description of the Preferred Embodiments
Employed a miniaturized potentiostat that combines the small size of the integrated Texas Instruments LMP91000 potentiostat chip (Texas Instruments, Dallas, TX, USA), with the processing power of Atmel 16 MHz, from Microchip Technology, on a custom-designed 44 mm by 50 mm circuit board. By incorporating onboard signal processing via Microprocessor ARDUINO NANO we achieve 1 mV voltage increment resolution and an instrumental limit of detection of 4.5 nA, Employed 2 independent 12 bit DAC to WE and CE to achieve enhanced resolution. This elegant engineering solution allows for high-resolution electrochemical analysis without requiring extensive circuitry.