Inexpensive ion-selective syringe electrode allows quantifying potassium levels in foods and drugs

The intensive development of new technologies in the field, especially related to the construction of new portable devices used as sensors for the detection of many compounds, has led to many surprising solutions. One of them is an electronic tongue that can answer various questions about unknown samples. These include providing seemingly unmeasurable information such as the presence and amount of certain compounds, contamination, spoilage, or taste.

However, such devices would not have been successful without the development of efficient, fast, and inexpensive sensors such as electrochemical sensors.

A recent paper published by researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences, led by Dr. Emilia Witkowska Nellie, demonstrates a low-cost, ion-selective syringe electrode that can be used to quantify potassium levels in a wide range of foods and pharmaceuticals. has been. supplement.

The study is published in the journal Electrochimica Acta.

One of the most important elements in the human body, after carbon, oxygen, nitrogen, and sulfur, is potassium. This element is involved in the regulation of intracellular pH, the reactivity of muscles such as the heart muscle, the regulation of blood pumps in the circulatory system, and the transmission of electrical impulses in nerves, which are closely related to the work of the nervous system. . .

Adequate potassium levels are not only related to proper blood pressure, but also to ensuring proper electrolyte balance and kidney function. Disturbances in potassium levels in the body can cause serious health problems, such as nerve necrosis, which prevents depolarization of heart cells, which can cause changes in heart rhythm, such as bradycardia.

Therefore, it is important to quickly and easily measure potassium levels in biological samples for quick and effective diagnosis. The same is important when monitoring various biologically important elements in the form of ions in samples.

In a new study, researchers have presented a quantitative, low-cost electrode array for measuring potassium levels in foods and drugs. This is a step forward in accurately, quickly and accurately measuring potassium levels in body fluids. However, prevention by consuming adequate potassium levels through a balanced diet is better than cure. Ensuring a healthy body, healthy mind, and adequate potassium levels in your food is paramount to maintaining good health.

A research team has presented a new system for measuring potassium levels in liquid food samples such as juices and mineral supplements. The system uses fast, non-destructive technology that operates at a high dynamic range compared to commercially available devices and does not require tedious recalibration. Their work emphasized low-cost analysis and the development of techniques that can be selectively and easily adapted to the analysis of a variety of samples. All of this is to make point-of-care devices available in the near future.

Why do we need sensors? Where did the idea for such research come from? Sensors detect the concentration of substances in various media, mainly liquids, such as blood, urine, saliva, water, etc. A device used for One of the most important characteristics of a sensor is its selectivity, or its ability to respond to: Displays only the chemical species of interest in the presence of other chemical species.

The sensor response is a result of the signal from the species you want to detect, but it is also influenced by interfering species, temperature, etc. Therefore, the sensor is calibrated for a specific type of sample. The sensor in a home blood glucose meter is prepared to accurately measure glucose in the blood with a finger prick. It can be used to measure glucose content in saliva or food, but the readings will not be accurate as the sensor is not calibrated for different pH or interfering species from other samples. .

In today’s world full of health threats, everything from diagnostic sensors to determine a patient’s health status and diagnosis to sensors to detect the presence and levels of specific compounds in a particular sample, such as a food sample, is becoming increasingly important. We need sensors in the field. It is often advantageous to use the same sensor for different types of samples.

To achieve their goal and demonstrate that the sensor can be used to directly measure species of interest in a variety of samples, the researchers used a well-known and long-used ion selection method based on the valinomycin ionophore. A sex electrode was used. Valinomycin is a recognition molecule used in sensors that provides high selectivity for potassium binding.

A disposable syringe was used to create the sensor, which was used as an alternative to the traditional expensive sensor body, and the use of selective ionophore not only provided high efficiency and accuracy, but also reduced the cost of potassium level analysis. . The low-cost syringe sensor features excellent selectivity and linear range.

“We describe a new and simple method to construct ion-selective electrodes using internal conditioning solutions. The electrodes can be easily fabricated from readily available materials, such as disposable syringe bodies. Comparison of the analytical parameters with standard ISE electrodes prepared using commercially available electrodes revealed that the proper functionality of the syringe sensor was further confirmed by analysis of the PCA loading and correlation matrix. Confirmed. ” Witkowska-Neri, who is responsible for this project.

However, as expected for this type of sensor, the results showed significantly higher accuracy, although for samples with more complex compositions and higher ionic strengths, such as beet soup, dried fruit, and tomato products. ​Assay precision was below acceptable limits. To obtain accurate readings, the sensor must be calibrated for each sample type.

A series of sensors was prepared to improve the accuracy of conducted measurements without requiring additional calibration for each new sample type. Different variations of sensors in the array were tested, in which the syringe played a key role.

In addition to the physical performance of the electrodes, appropriate algorithms needed to be optimized to exploit information from different electrodes in media with complex chemical compositions. Various methods ranging from Partial Least Squares (PLS), Multivariate Linear Regression (MLR), Principal Component Regression (PCR), and Random Forest (RF) algorithms to determine potassium concentration in real samples was used. RF is an ensemble. How to combine multiple decision trees to obtain a single result.

The researchers also tested whether it would be possible to replace the best but expensive valinomycin ionophore with a much cheaper but less selective corona ether.

Elżbieta Jarosinska, principal investigator of the project, said: “Compared to the quantification of potassium using a standard calibration curve, the root mean square error of prediction was almost six times lower. We also showed how to design arrays for this purpose.” Comparable analytical performance can be obtained by substituting valinomycin with a less selective ionophore, such as dibenzo-18-crown-6. ”

Tests were prepared on real samples such as mineral water, tomato juice, banana juice, dried dates, tomato sauce, concentrated beet soup, and pharmaceutical potassium supplements. The performance of the proposed syringe-based system and the proposed valinomycin replacement is highly impressive in determining potassium content in many complex samples containing other ions and organic substances that may affect detection. It shows high effectiveness.

The proposed methodology can also be used in biomedical diagnostics to increase measurement accuracy when using commercially available sensors. Using the methodology developed by Dr. Witkowska-Nery’s group, tests for cholesterol, HDL, LDL, triglycerides, and more can be made more accurate by changing only the calibration procedure without changing the measurements. There is a gender.

In addition to being curious during research, scientists working on the aforementioned projects emphasize the importance of simplifying the path to achieving your goals. These days, creating diagnostic points that are accessible to everyone requires that the methods used be simple and the cost of testing low. It is these factors that the authors of this study focus on.