The overall operation process of a continuous flow chemical analyzer is relatively standardized, but the specific complexity depends on the instrument model, analysis items, and user experience. The following analysis focuses on three aspects: operational steps, key points, and simplification techniques to help quickly grasp its logic:
1、 Overview of Operation Process (Taking Common Water Quality Analysis as an Example)
1. Preparation before startup (about 15-30 minutes)
Preparation of reagents and consumables:
Prepare the required reagents (such as color reagents, buffer solutions, reducing agents, etc.) according to the analysis project, paying attention to the purity of the reagents (analytical grade or above) and the shelf life;
Install or replace the peristaltic pump tube (to avoid deformation caused by excessive compression), connect the sample tube, reagent tube, and waste liquid tube, and ensure that the tubing is free of bubbles and leaks.
Instrument inspection:
Confirm that the power supply, cooling water, and gas (if necessary) are connected properly;
Clean the injection system (such as sample tray, flow cell) to avoid cross contamination.
2. Power on and parameter settings (10-20 minutes)
Start software:
Open the instrument control software, select the analysis method (such as built-in standard methods for ammonia nitrogen, total phosphorus, etc.), or customize parameters (flow rate, temperature, wavelength, etc.).
Key points for parameter setting:
Flow rate: The rotational speed of the peristaltic pump determines the mixing ratio of reagents and samples (usually 1-5 mL/min), which needs to be adjusted according to the method requirements;
Temperature: For projects involving heating reactions (such as digestion), the temperature of the reaction coil should be set (such as 100 ℃± 2 ℃);
Wavelength: Select the detection wavelength based on the characteristic absorption peak of the color reaction (such as 420nm for ammonia nitrogen).
3. Calibration and Blank Test (30-60 minutes)
Blank correction:
Run pure water or reagent free blank, deduct background values (such as pipeline residue, reagent color interference).
Standard curve drawing:
Inject different concentrations of standard solutions (such as 0.1, 0.5, 1.0mg/L) in sequence, and the software will automatically generate standard curves (with a required correlation coefficient R ² ≥ 0.999).
Key Tip:
Standard solutions need to be prepared or stored according to regulations to avoid concentration drift;
Each batch of samples needs to redraw the standard curve to ensure accuracy.
4. Sample analysis (time varies with sample size)
Sample injection operation:
Place the samples in the sample tray in order and set the injection interval (to avoid the residual effect of the previous sample on the next one);
Start the analysis program, and the instrument automatically completes sampling, mixing, reaction, colorimetry, and data recording.
Process monitoring:
Observing baseline stability: Under normal circumstances, baseline fluctuations should be ≤ ± 1% absorbance;
Pay attention to abnormal peak shapes: such as peak broadening or tailing, which may indicate pipeline blockage or unstable flow rate.
5. Shutdown and maintenance (20-30 minutes)
Pipeline cleaning:
Rinse the pipeline with pure water or dilute acid (such as 5% HCl) for 10-15 minutes to remove residual reagents (especially after high salt or high concentration samples);
Long term shutdown requires ethanol flushing to prevent microbial growth.
Component maintenance:
Release the cover of the peristaltic pump to extend the service life of the pump tube;
Clean the colorimetric dish or circulation pool to avoid stains affecting the light transmittance.
Record filling:
Register instrument usage time, sample quantity, maintenance content, and abnormal situations.
3、 Practical tips for simplifying operations
1. Pre experiment optimization parameters
Before formal analysis, use simulated samples (such as known concentration solutions) to test parameters such as flow rate and temperature to ensure peak symmetry and stable retention time.
2. Pipeline identification and color coding
Use different color labels to distinguish between sample tubes and reagent tubes (e.g. blue=sample, red=reagent), reducing connection errors.
3. Batch processing and automatic sampling
Using the automatic sampler of the instrument (such as turntable or track type), load 30-100 samples at once to reduce manual intervention.