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To quantify the content of sodium in blood serum, a low-cost microcontroller-based Sodium analyzer has been created. The hardware consists of an ATmega8535-based microcontroller and its related peripherals. This article goes into the specifics of interface, calibration, and operation method. The sensor for the measurement is the Sodium Ion Selective Electrode (ISE). To measure, analyze, and show the data, software written in the 'C' programming language is used. Blood samples are taken from a large number of patients. The sodium concentration in the samples is determined. The instrument's performance is investigated using linear regression analysis.

Sodium is a necessary component of everyone's diet; it aids in the maintenance of cell water balance as well as the function of nerve impulses and muscles. When it comes to open heart surgery and renal care, blood electrolyte sodium is extremely important in determining the course of treatment. Sodium consumption is one of the elements that contribute to the development of hypertension (blood pressure greater than 150 mmol/L). Excess salt consumption can cause edema or water retention. Even if calcium consumption is adequate, women in menopause (low of oestrogen) who drink too much sodium may be at risk for osteoporosis. When serum sodium levels fall below 132 mmol=L, hyponatremia ensues. Although hyponatremia affects people of all races and genders equally, it is more common in the elderly due to the greater frequency of comorbidities that might cause serum levels to drop (e.g., cardiac, hepatic, or renal failure). [1] The daily salt requirements are around 1,500 mg (70 mmol) and 2,300 mg (100 mmol), respectively. [2]

Flame photometry, spectrophotometry, colorimetry, and ISE techniques are some of the methods used to determine sodium ion concentration in blood serum. The first three methods take a long time to complete. The percentage of accuracy is lower in the ISE approach, and sample conditioning= preparation is time-consuming. As a result, the ion selective electrode method is utilized to detect sodium electrolyte in blood. [3,4] The goal of this project is to create a low-cost microcontroller-based instrumentation system that can measure sodium ion concentration in blood serum using a sodium ISE sensor. With the right interface, the microcontroller can be used to determine sodium ion concentrations in a variety of ways. The microcontroller's benefits in processing the sodium ion analysis contribute to the device's increased measurement accuracy and robustness in rejecting noise and identifying false results. The microcontroller also provides the ability to store test results for further reference.[5]

Design Scheme

Figure 1 depicts the design concept for the microcontroller-based sodium concentration measurement system. The ATmega8535 microcontroller in Block A is at the heart of the measurement system. It has an 8-Kbyte In System Programmable Flash with Read-Write capabilities, 512-byte EEPROM, 512-byte SRAM, 32 general purpose I/O lines, 32 general purpose working registers, a serial programmable USART, an 8-ch 10-bit ADC, and a Programmable Watchdog Timer with Separate On-chip Oscillator[6]. A Sodium Ion Selective Electrode sensor is found in Block B, and it converts sodium ion concentration into voltage. The output of the sodium ion ISE sensor is amplified appropriately in Block C using an instrumentation amplifier. The ATmega8535 microcontroller (Block A) receives the amplified output signal and processes the input data. A stepper motor and pump motor configuration are found in Block D. The ISE Electrode is moved up and down by a stepper motor to take measurements, while the calibrator1 solution is pumped by a pump motor. The microcontroller receives commands and information via a keypad housed in Block E. The results are shown on a Hitachi four-row 20-character alphanumeric LCD display in Block F. The results can be sent to a PC through an RS232 port for additional analysis. In block G, the IC MAX232 is a dual RS232 transmitter=receiver interface circuit that complies with all EIA RS232 specifications. It serves as a link between the microcontroller and the computer (Block H).

Block diagram of microcontroller based sodium ion analyzer.

Block diagram of microcontroller based sodium ion analyzer.

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