Direct Determination of Gas pH and Carbon Dioxide Concentration with pH Electrodes

Abstract

A simple apparatus to measure gas pH and carbon dioxide (CO 2 ) concentration was designed for undergraduate students in the analytical chemistry laboratory. Gas passed through a flow meter and a mixer, then reached the homemade measuring chamber and caused the potential change of a pH combination electrode. Poly(ethylene glycol)-20000 aqueous solutions with hygroscopicity and nontoxicity were used as reaction media by forming absorption liquid films around the junction point and the bulb of the pH combination electrode. A laboratory-made voltage follower and a N2000 chromatography data system were used to transform impedance and record data, respectively. Gas samples containing 10−100% CO 2 were measured with the apparatus, and fast potential responses for different concentrations of CO 2 were obtained. This apparatus is more cost-effective and ecofriendly as compared with other conventional methods.

Introduction to Validation of Analytical Methods: Potentiometric Determination of CO2

“…After the average percentage of recovery (PRec) was obtained, by means of eq 5, for the regular and altered conditions, PRec o and PRec i , respectively, the absolute difference |d i | = |PRec i − PRec o | was determined to evaluated the robustness of the method: the smaller the |d i |, the more robust the method. It has been established 18 that, after altering a factor, a |d i | ≥ 3% indicates the robustness of the method is compromised. Table 1 compiles the results obtained for the described challenges to the method; see Supporting Information, section 1.6.…”

“…17 Moreover, quantification of CO 2 is a fundamental element of quality assurance in fields such as agricultural industry and food. 18 For instance, CO 2 detection and quantifications are carried out by practically any soft drinks, mineral water, and breweries producers. 17,19 The aims of the present work are first, to present the performance of a series of parameters needed to validate a potentiometric method to quantify CO 2 in carbonated drinks.…”

“…Applications of this sensing electrode include CO 2 measurements in blood, CO 2 generated from metabolic processes in plants, and determination of urea and oxalate . Moreover, quantification of CO 2 is a fundamental element of quality assurance in fields such as agricultural industry and food . For instance, CO 2 detection and quantifications are carried out by practically any soft drinks, mineral water, and breweries producers. , …”

The Effects of Soil Moisture on Carbon Dioxide Emission in Tibetan Plateau

“…CO2 data is tropospheric. The mobility of carbon dioxide in the troposphere is too strong, and the molar mass fraction changes all the time but uncertainty of carbon dioxide molar mass fraction monitored by satellite [7]. The experiment can only rely on site monitoring to get more specific and accurate data and results.…”