How to choose a liquid chromatograph

How to choose a liquid chromatograph
One. Excellent technical indicators

The first is how to look at the indicators. There are many indicators for liquid chromatographs, such as pumps, detectors, columns, and so on. We believe that depending on the main technical indicators, according to national standards, the main indicators of the instrument are noise, drift, minimum detection concentration, qualitative and quantitative repeatability. These indicators should be placed in the system, in the loop to see, to compare. It is necessary to connect all the unit devices, such as connecting the column, the injection valve, and the mobile phase. Because you can also analyze after you have connected in the analysis, instead of using a detector or pump alone.

Then on this basis, we will compare these main indicators.

1. noise

It refers to the high frequency noise generated by the electrical components of the instrument, temperature fluctuations, linear pulses of voltage and other non-solute effects and irregular fluctuations in the baseline. The size of the noise is directly related to the detection sensitivity of the instrument. The louder the noise, the lower the sensitivity of the detection. For the detection of low content of the sample, the instrument noise is required to be as small as possible. Otherwise, excessive noise will cause the baseline to be unstable and even affect the analysis results.

2. Minimum detection concentration (minimum detection limit)

It is an important parameter that reflects the sensitivity of the instrument. CL=2×Nd×C/H (CL: minimum detection concentration Nd: noise C: minimum concentration of sample concentration H: peak height of sample) It can be seen from the above formula that the minimum detection concentration is proportional to the noise, and the noise is larger. The smaller the minimum detection concentration, the lower the sensitivity. Some manufacturers have avoided this indicator, indicating that they are not willing to compare noise based on the minimum detection concentration.

3. drift

It refers to the distance that the baseline drifts away from the origin for a period of time after the instrument is stable. It is usually used to measure the stability of the instrument. High-quality instruments can be stabilized in a short period of time, which improves the efficiency of analysis to some extent.

4. Qualitative quantitative repeatability

It is mainly an indicator for assessing the stability of the instrument, which is very important for analyzing samples. The stability of a good instrument should be very good, which requires multiple injection retention time and consistency of content, so the results can be convincing.

Some friends will think that these indicators seem to be detectors. Yes, but the conditions mentioned above are to be placed in the entire loop and system to see and compare. For example, pump pulsation will directly affect the noise index, pump flow accuracy, accuracy indicators, and poor sealing will also affect the relevant indicators. So look at the indicators systematically. For example, in some of the published indicators, the noise and drift indicators are written on an empty pool or some are not written. This indicator only evaluates the optical and electrical characteristics of the UV detector, which is far from the actual situation. It does not test the pressure pulsation of the pump, the damping of the flow circuit and the performance of the UV detector flow cell. Therefore, we believe that some of the above indicators can reflect the true level of the instrument.

two. Easy to operate

Operational convenience is important for both novice and mature users. The simpler the operation, the better the analysis efficiency, and the powerful help for the expansion of the analysis method. The WS-100 workstation software of Shanghai Wufeng Scientific Instrument Co., Ltd. realizes truly intelligent operation. It abandons the previous concept that workstation software can only be used for data processing. It is the first to introduce software that integrates control and post-processing in China, which brings great convenience to users in operation and use.

three. Systematic, overall development

This refers to the overall development of the instrument and is a complete system. This phenomenon is currently on the market, saying that my pump is imported, or how good the detector is, how many imported parts are assembled, and so on. In fact, this is a misunderstanding. Liquid chromatography is a complex system, not developed as a whole. The indicators, software and hardware, hardware and hardware are not matched. The overall level is not high, and the user is not satisfied with the after-sales service. responsible.

The main advantages of the overall development are: unified technical indicators, communication coordination of various units of the instrument, the ability to establish an overall digital evaluation system, reflecting the company's technology and development strength.

The products of well-known foreign instrument manufacturers are also developed as a whole, so the overall level of the instrument can be guaranteed.

Shanghai Qite Analytical Instrument Co., Ltd.: http://

telephone / fax

Http:// Submission:

First Grade Silicon Carbide

First Grade Silicon Carbide,Silicon Carbide For Abrasive,Silicon Carbide For Refractories,Metallurgical Grade Black Silicon Carbide

ningxia hexing carbon based materials ,