【2025 Analytical Instruments】Selection of Online Analytical Instruments

The following response is not part of the attachment and is provided for reference only: Analytical instruments are an essential component of industrial automation, used to detect and analyze the composition, concentration, or other important chemical and physical parameters of substances. They are widely used in industries such as chemicals and environmental protection, helping enterprises improve product quality, optimize production processes, and ensure safe production.

1. Gas analysis instruments: Gas analyzers are used to detect and analyze the components and concentrations in gas samples, and they are widely applied in fields such as environmental monitoring, control of industrial exhaust emissions, and safety monitoring. Common gas analysis instruments include: (1) Infrared Gas Analyzer (IRGA), which analyzes the components in gases by utilizing the property of absorbing infrared radiation, and is particularly suitable for measuring the concentrations of gases such as carbon dioxide, carbon monoxide, methane, and nitrogen. It is commonly used in environmental monitoring and industrial exhaust gas detection. (2) Chemiluminescence detectors (CLD) analyze gas concentrations by utilizing the luminescence generated from the reaction between gases and chemical reagents, and are commonly used for the detection of nitrogen oxides (NOx). (3) Gas chromatograph (GC): Based on the principles of gas chromatography, it separates the various components in a gas mixture and performs quantitative analysis; it is widely used in fields such as petrochemical industry, environmental testing, and food analysis. Gas chromatographs can accurately analyze the complex components in gas samples, and are particularly suitable for the detection of volatile organic compounds (VOCs) and gas pollutants. (4) Electrochemical gas analyzers analyze the composition of gases by generating an electric current through chemical reactions between the gases and electrodes; they are commonly used for detecting oxygen, carbon monoxide, hydrogen, etc., and are widely applied in industrial gas monitoring, indoor air quality testing, and laboratory analysis.

2. Liquid analysis instruments: Liquid analyzers are used to detect and analyze parameters such as chemical composition, concentration, and pH value in liquid samples. They are widely used in fields such as water quality monitoring, the pharmaceutical industry, and food processing. Common liquid analysis instruments include: (1) pH meters, which are used to measure the acidity or alkalinity of liquid solutions and are among the most common instruments in liquid analysis. It is widely used in fields such as environmental monitoring, water treatment, and chemical analysis. (2) A conductivity meter is used to measure the electrical conductivity of liquids, thereby determining the ion concentration in them. It is commonly used in industries such as water treatment, food, and pharmaceuticals. (3) Ion-selective electrodes (ISE) are used for the analysis of the concentration of specific ions, such as sodium ions, calcium ions, chloride ions, etc. It is widely used in fields such as water quality analysis, chemical experiments, and food safety monitoring. (4) Spectrophotometer: It determines the concentration of chemical substances in a sample by analyzing the absorption or transmission of light of specific wavelengths by that sample. It is widely used in water quality analysis, food testing, environmental monitoring, etc. It is not only used for water quality analysis, but also provides high-precision quantitative analysis in various fields such as chemical experiments, food quality testing, and pharmaceutical analysis.

A gas chromatograph is a commonly used instrument for analyzing gases and volatile liquid mixtures. It separates and quantitatively analyzes different components based on their retention times, by vaporizing the sample and then allowing it to distribute between the stationary phase and the mobile phase. It is commonly used in fields such as petrochemical industry, environmental monitoring, and food and pharmaceutical analysis. Gas chromatographs can provide high-resolution separation, making them suitable for the detection of trace components in complex gas samples.

A mass spectrometer is an instrument that analyzes the mass-to-charge ratio (m/z) of substances based on ionization. Mass spectrometers can be used in combination with gas chromatographs (GC) or liquid chromatographs (HPLC), and are widely applied in fields such as environmental monitoring, drug analysis, food safety, and the study of chemical reaction mechanisms. Mass spectrometers are primarily used for the qualitative and quantitative analysis of complex samples, and are especially suitable for in-depth analysis of compounds with complex chemical compositions.

Thermal analysis instruments are used to analyze the changes in the thermal properties of substances during heating and cooling processes, and are commonly employed in fields such as materials science and chemical analysis.

Auxiliary devices in online analytical instruments: sampling device, preprocessing device, constant temperature controller.

The functions of the sampling, preprocessing, and injection systems are to obtain representative samples from the process, adjust their composition to meet the requirements regarding the sample conditions for analysis, and then feed them into the analyzer.

The function of an analyzer is to convert the amount of components (or physical properties) in a sample being analyzed into measurable values.

Display and data processing systems are used to indicate and record data on analysis results, and to convert them into corresponding electrical signals that are sent to automatic control systems in order to automate the production process.