The core principle of the continuous flow chemical analyzer is to drive the mixing reaction between the sample and the reagent through the continuous flow of the carrier liquid, achieving automated and continuous component analysis. The key is to use the chemical reaction and detection system during the flow process to quickly obtain the concentration information of the target component in the sample.
1、 Core process: from sample introduction to result output
The working process of a continuous flow chemical analyzer can be divided into several closely connected steps, presenting a continuous flow state as a whole without the need for manual intervention.
Sample introduction: Through an automatic sampler, the sample to be tested (such as water quality, soil extract, blood, etc.) is quantitatively injected into the analysis system at a set frequency (such as 30-120 samples per hour). Samples are usually cut into discrete 'sample segments', each separated by a carrier liquid (usually distilled water or buffer) to avoid cross contamination between samples.
Reagent mixing and reaction: The sample section flows along a closed pipeline (such as polyethylene or polytetrafluoroethylene tube) under the push of the carrier liquid, and is sequentially mixed with different reaction reagents (determined according to the detection items, such as color reagents, oxidants, etc.). There may be a mixing ring in the pipeline (increasing the contact area through a spiral structure) to promote sufficient reaction between the sample and the reagent, generating products with specific optical properties such as color, fluorescence, and absorbance changes.
Detection and signal conversion: The mixed solution after the reaction flows into a detector (commonly used spectrophotometers, fluorescence detectors, etc.), which measures the characteristic signals of the reaction products (such as absorbance at specific wavelengths), converts the optical signals into electrical signals, and transmits them to the data processing system.
Data processing: The system establishes a calibration curve based on the signal of the standard sample, calculates the concentration of the target component through the signal of the sample to be tested, and finally outputs the result in digital or graphical form.
2、 Key design: Ensure continuous flow and reaction efficiency
Continuous flow system: Throughout the entire analysis process, the carrier liquid, sample, and reagent flow continuously in the pipeline, without the need to process each sample individually like traditional manual analysis, greatly improving the analysis speed.
Bubble separation technology: Some instruments introduce bubbles into the sample section or reagent, which can reduce the adsorption of the sample on the inner wall of the pipeline, enhance the mixing effect, and avoid diffusion mixing between adjacent sample sections.
Thermostatic control: Many reactions require specific temperatures (such as enzymatic reactions), and the instrument maintains the reaction pipeline at a set temperature (such as 37 ℃) through a thermostatic bath or heating module to ensure reaction efficiency and stability.
3、 Differences from traditional methods: why is it more efficient?
Compared with traditional methods such as manual titration and discrete analysis, the core advantage of continuous flow chemical analyzers lies in "continuity" and "automation": in traditional methods, steps such as sample processing, reagent addition, reaction waiting, and detection need to be manually completed, which is inefficient and prone to introducing human errors; Continuous flow analysis achieves full process automation through mechanical devices, with continuous sample injection and synchronous reaction. It is not only suitable for batch sample analysis, but also improves the repeatability and accuracy of results by strictly controlling reaction conditions such as time, temperature, and reagent ratio.
Summary: The Essence of Continuous Flow Chemical Analysis
The working principle of a continuous flow chemical analyzer can be summarized as follows: using a continuously flowing carrier liquid as a carrier, it realizes automatic sample injection, online mixing reaction with reagents, real-time detection of characteristic signals, and finally calculates the concentration of target components through calibration curves. Its core is to integrate the traditional step-by-step chemical analysis process into a continuous automated process, thereby achieving efficient and accurate batch sample analysis, which is widely used in environmental monitoring, food testing, clinical testing and other fields.