TD-DFT Guided Advanced E-Eye Sensing Technique for On-site Quantification of Fe, Cr, F, and As in the Environmental, Biological, and Food Samples

Scope of this research is to develop a portable point of care device. It is termed as e-Eye which will be able to measure the concentration of toxicant in multi metrics sample. The experimental challenges associated with the current POCT device is the selectivity, selectivity in a multi matrix sample.

And another challenge is the detection of the very low concentration. At this moment, it cannot detect very low concentration. And last point is that that detecting a particular analyte, particular target in a multi matrix sample.

See this indigenously developed e-Eye sensor basically mimics the spectrophotometer portable EV visible spectrophotometer. Here e-Eye stands for optical sensor. This device is developed based on the two working principle.

First of all, cardiometric chemical sensor working principle of that. Second one is the working principle of optical sensor with a high precision. We have tried to understand the fundamentals of this work to working principle, time dependent density function theory concept, we have applied for the optical comediate sensors.

Our inventions address the basic fundamental questions from computational domain to sensor device development. How we can develop, that we have answered. And based on this working basically, our concept, we can understand the mechanism of the system.

We can predict the selectivity. We can predict the range of detection, all these things. Our future objective is to develop precise higher based sensor, which will be able to address the quality of the water monitoring issues.

And it can be applicable in the agricultural field, environmental field, as well as the healthcare field. And it will be able to detect element compound in even some bio organisms from the sample. To begin, select a lock and key reaction that specifically recognizes the targeted analyte based on its fundamental chemistry.

Launch the Gaussian 09 program to perform all the calculations using the Becke, 3-parameter, Lee-Yang-Parr, B3LYP hybrid method, and the Los Alamos National Laboratory 2 double Z basis set to obtain more accurate results in electronic computation involving the targeted analyte. In the Gaussian Input add SCRF=PCM and choose water and confirm the setting and show the input containing geometry equals connectivity and bonded atom list in the connectivity block. Click submit.

Compute the ground state energy required to compute the optimized structure of the molecule. Obtain excited state electronic transitions using the time-dependent self-consistent field method, requesting a number of states equal to 60. With the same method and solvent model compute and export the predicted ultraviolet absorption spectrum.

Perform a ground state density functional theory geometry optimization using the B3LYP functional with the LANL2DZ basis set to refine the molecular structure. Export the optimized structures of 110 phenenferrline and the ferrous ion for subsequent studies. Transfer equal volumes of trisodium citrate dihydrate as masking agent, ascorbic acid as pH optimizing agent, and 110 pheanphroline into a transparent glass culture tube.

Add two milliliters of stock solution to reach a total volume of five milliliters. Place each sample and standard in a quartz cuvette with a one centimeter path length and keep all measurements at room temperature under standard laboratory conditions. Measure iron in all standards and samples using UV visible spectroscopy by scanning from 250 to 750 nanometers.

Configure the instrument settings to match the specified conditions by selecting scan speed as medium. Set measurement type to absorbance. Adjust slit width to five nanometers and set the detectors to direct.

Perform baseline correction using a blank that contains the same water matrix as the samples. After UV absorbance is recorded, Lambda max is observed at 510 nanometers, which confirms the formation of the complex. To begin procure an LDR, a white LED and LCD, a microcontroller or microprocessor board, and precision resistors.

Using the three dimensional printed box, align the LED and the light dependent resistor directly opposite each other across the cuvette slot. Complete the circuit by installing a 3.3 kiloohm series resistor for the LED, routing clean wiring and connecting the LCD model number 11497. Interface the sensor with the microcontroller across a voltage divider that converts light dependent resistor resistance changes into a measurable voltage.

Install analog noise suppression filters by adding a 10 kiloohm series or biasing resistor and a one microfarad capacitor to form a low pass network at each analog input. Place components close to the microcontroller pins and route short twisted signal leads to improve stability. Print the printed circuit board when the prototype schematic and layout are finalized and electrically verified.

Supply power by turning on the electronic switch and record the sensor response as resistance or converted voltage from each channel. Observe the light path as the LED passes light through the reaction chamber and the light dependent resistor senses transmitted intensity corresponding to farro information. Correlate the measured resistance with ferrous ion concentration to generate a calibration plot and enter the resulting equation into the device algorithm for real-time reporting.

Review the complete circuit drawing to confirm final wiring and channel assignments. Then print and assemble the finished device enclosure. Create four dedicated slots in the three dimensional box to hold four cuvettes in fixed positions.

Isolate each detection slot both optically with opaque physical barriers and electronically with separate LED and light dependent resistor pairs and individual voltage dividers to prevent signal overlap. Assign one slot to a single analyte and keep the assignment fixed. Ensure the cuvette placed in each slot contains only the reagent specific to that analyte.

Turn on the main switch to supply power so that all four LEDs illuminate simultaneously. Allow the light dependent resistors to sense each analyte in parallel and display the results for all channels at once. The multiplexed prototype accurately quantified total iron concentrations in peanut samples with results closely matching the UV vis spectrophotometer and remaining above the limit of detection in all cases.

The chromium and fluoride levels measured in hair samples using the multiplexed prototype were comparable to UV visible measurements. Arsenic levels in brahmaputra water samples increased progressively across sample numbers and were reliably detected by both the multiplexed prototype and UV vis system.