Column efficiency determination of high performance liquid chromatography: high performance liquid chromatography column uses liquid as the mobile phase, and obtains a relatively high flow rate with the help of a high-pressure infusion pump to increase the separation speed, and is made of a highly efficient stationary phase with extremely fine particles The chromatographic method of separation and analysis on the chromatographic column. In high performance liquid chromatography, if a non-polar stationary phase is used, such as an octadecyl bonded phase and a polar mobile phase, and a reversed-phase chromatographic separation system is formed.
Prevention of blockage in HPLC Column
The mobile phase used in reversed-phase chromatography systems has a lower cost and is more widely used. In quantitative analysis, in order to facilitate accurate measurement, it is required to have a good separation between the quantitative peak and other peaks or internal standard peaks.
Because the filler particles are very fine, the chromatographic column cavity is very small, and the fine particles in the solvent and the sample can block the chromatographic column. Solvents and fine particles in the sample will increase the clogging and wear of the injection valve, and will also increase the wear of the piston rod and piston in the pump head. In short, try to use high-purity reagents as the mobile phase.
Factors Affecting Separation Efficiency in HPLC Column
The mobile phase used in HPLC must be degassed beforehand; otherwise, bubbles will easily escape in the system and affect the operation of the pump. Air bubbles will also affect the separation efficiency of the column, the sensitivity of the detector, the stability of the baseline, and even make it impossible to detect. In addition, the oxygen dissolved in the mobile phase may also react with the sample, the mobile phase, and even the stationary phase. Dissolved gas can also cause changes in the pH of the solvent, which can cause errors in the separation or analysis results.
Dissolved oxygen can form UV-absorbing complexes with some solvents. This complex will increase background absorption and cause a slight decrease in detection sensitivity, but more importantly, it will cause baseline drift or formation during gradient elution.
Degassing Method in HPLC Column
In fluorescence detection, dissolved oxygen can also cause quenching under certain conditions. In some cases, the fluorescence response can be reduced by up to 95%. In electrochemical detection, the influence of oxygen is greater. Generally speaking, the gas in the organic solvent is easy to fall off, while the gas in the aqueous solution is more stubborn. Blowing helium in the solution is a very effective degassing method. This continuous degassing method is often used in electrochemical detection.
Beginners Guide Of Choosing HPLC Columns
High performance liquid chromatography (HPLC) is Well known as a kind of essential tool in the lab worldwide, with the ability to separate, identify, and quantitate the compounds presented in any sample which can be dissolved in the liquid.
To perform HPLC, we need an HPLC column tube and fittings that contain the chromatographic packing material, which is called the stationary phase as well. The column must withstand the back pressure which is created during separating. Providing a flow path for the sample at its inlet, and analyte bands at its outlet, the HPLC column also needs to be well-controlled with no leaking and zero-dead volume. The column should be chemically inert relative to the separation system not only the sample and mobile but the stationary phases too.
Hawach HPLC columns are constructed of stainless steel for the highest pressure resistance, prepacked with the different stationary phases. C18 HPLC columns are in the first place by offering the perfect hydrophobic separation power and high surface area coverage. Compared to a C18, when less retention is needed, C8 HPLC columns will be the better choice. C4 HPLC columns and C5 HPLC columns are used when separating the large macromolecules. Besides the prepacked columns, Hawach also has empty HPLC columns available.