The influence of different ionic concentration in cell physiological solution on temperature measurement by near infrared

It is important to real-timely monitor and control the temperature of cell physiological solution in patch clamp experiments, which can eliminate the uncertainty due to temperature and improve the measurement accuracy. This paper studies the influence of different ions at different concentrations in the physiological solution on precision of a temperature model by using near infrared spectroscopy and chemometrics method. Firstly, we prepared twelve sample solutions respectively with the solutes of CaCl₂, KCl and NaCl at four kinds of concentrations, and collected the spectra of different solutions at the setting temperature range 20~40℃, the range of the spectra is 9 615~5 714 cm^-1. Then we divided the spectra of each solution at different temperatures into two parts (a training set and a prediction set) by three methods. Interval partial least squares method was used to select an effective wavelength range and develop calibration models between the spectra in the selected range and temperature velues. The experimental results show that RMSEP of CaCl₂ solution with 0.25 g·mL^-1 is maximum, the result of the three tests are 0.386 3, 0.303 7 and 0.337 2℃, RMSEP of NaCl with 0.005 g·mL^-1 solution is minimum, the result of the three tests are 0.220 8, 0.155 3 and 0.145 2℃. The experimental results indicate that Ca²⁺ has the greatest influence on the accuracy of the temperature model of the cell physiological solution, then K⁺, and Na⁺ has the least influence. And with the ionic concentration increasing, the model accuracy decreases. Therefore, when we build the temperature model of cell physiological solution, it is necessary to change the proportion of the three kinds of main ions in cell physiological solution reasonably in order to correct the effects of different ionic concentrations in physiological solution and improve the accuracy of temperature measurements by near infrared spectroscopy.