How to use the LC-2050 series liquid chromatograph

The general usage steps of the LC-2050 series liquid chromatograph are as follows:

Preparation before use

Inspect the instrument: Check if there is any damage to the appearance of the instrument and whether the connections of all components are normal, such as whether the connections of the infusion pump, injector, chromatographic column, detector, etc. are stable.

Prepare the mobile phase: According to the analysis requirements, prepare the mobile phase. High-purity solvents should be used, filtered and ultrasonically degassed to remove bubbles and impurities, so as to prevent affecting the test results and damaging the instrument.

Install the chromatographic column: Carefully install the chromatographic column on the corresponding interface of the liquid chromatograph, making sure the direction is correct and the connection is tight to avoid leakage.

Preheating upon startup: Connect the power supply, turn on the liquid chromatograph, and let the instrument preheat for a period of time to ensure that all components reach a stable working state. The general preheating time is 15 to 30 minutes.

Parameter setting

Infusion pump parameters: Set the flow rate. Determine the appropriate flow rate based on the nature of the sample and the analysis requirements. The common flow rate range is 0.1-5 mL/min. Set a pressure limit to prevent the infusion pump from being damaged due to excessive pressure. Generally, it is set to a value slightly higher than the normal working pressure.

Sampler parameters: Set the injection volume and select the appropriate injection volume based on the sample concentration and analytical accuracy requirements. Common injection volumes range from 1 to 20 μL. Select the injection mode, such as manual injection or automatic injection.

Detector parameters: Set the detection wavelength and select the appropriate detection wavelength based on the absorption characteristics of the target compound in the sample. Adjust the sensitivity so that the detection signal is within an appropriate range, which can accurately detect the target compound without causing saturation due to an overly strong signal.

Injection analysis

Manual injection: If manual injection is adopted, a certain amount of sample solution is drawn with a microsyringe. After expelling the air bubbles in the syringe, insert the syringe into the injection port of the injection valve, slowly push the syringe to inject the sample, and then quickly turn the injection valve to the injection position to start the analysis.

Automatic sampling: If an automatic sampler is used, place the sample bottle containing the sample on the sample rack of the automatic sampler, set the position of the sample bottle, the sampling sequence and other information, start the automatic sampling program, and the instrument will sample and analyze in sequence according to the set parameters.

Data acquisition and processing

Data acquisition: After starting the analysis program, the instrument begins to separate and detect according to the set parameters, and at the same time, the data acquisition system starts to record the detection signals. During the analysis process, closely observe whether the baseline is stable and whether the peak shape is normal, etc.

Data processing: After the analysis is completed, the collected data is processed using the software that comes with the liquid chromatograph. It can perform operations such as peak identification, integral calculation of peak area and peak height, and quantitative analysis. Calculate the content of the target compound in the sample according to methods such as the standard curve or the internal standard method.

Shutdown and maintenance

Shutdown: After the analysis is completed, stop the data collection first, then turn off the power of the detector, infusion pump and other components in sequence, and finally turn off the main power of the liquid chromatograph.

Cleaning system: Clean the infusion pump, injector and chromatographic column with appropriate solvents to prevent residual samples from remaining in the system and causing blockage or contamination. Generally, it is first rinsed with the mobile phase for a period of time, and then rinsed with pure solvents (such as methanol, acetonitrile, etc.).

Maintenance and care: Regularly maintain and care for the instrument, such as replacing the rotor and gasket of the injection valve, cleaning or replacing the packing material of the chromatographic column, and inspecting the sealing parts of the infusion pump, etc., to ensure the stable performance and service life of the instrument.