First, how is the liquid chromatograph peak fork?
The cause of this is generally caused by contamination of the column or collapse of the column packing.
In the first case, first flush the column with pure water, then replace it with methanol, then rinse the column with methanol + isopropanol (4+6) (the length of the rinse time is determined by the contamination of the sample), and then Rinse with methanol, rinse with pure water, and finally rinse with methanol for more than 30 minutes. If the peak is still poor after rinsing, consider the second case.
In the second case, unscrew the column head and check that the column packing is indented or collapsed. Remove the indurated part (contaminated packing), fill in the new packing, drop a drop of methanol, fill the packing, refill, press with a smooth stainless steel rod with the same inner diameter of the column, fill it again, drop the methanol, and then press it again. Once, until it is filled and filled. Rinse the column head with methanol, wipe the packing on the outer wall of the column, tighten the column head, and rinse with pure methanol for more than 30 minutes.
Second, how to eliminate the bubble overflow of the liquid chromatograph?
The generation of bubbles in the mobile phase cannot be removed, mainly because the filter is immersed in a buffer such as ammonium acetate for a long time. The inside of the filter grows due to the growth of mold, forming a cluster of bacteria, blocking the filter, and the buffer is difficult to smoothly. Through the filter, the air enters the mobile phase through the filter under the pressure of the pump.
The filter is immersed in a 5% nitric acid solution and ultrasonically cleaned for a few minutes. The filter can also be immersed in a 5% nitric acid solution for 12 to 36 hours, gently vortexed several times, and then the filter is washed several times with pure water. Open the pressure relief valve, open the purge button to clean the degassing. If there are still bubbles emerging from the filter, continue to soak the filter in a 5% nitric acid solution. If there are no bubbles, the filter will emerge from the filter, indicating the inside of the filter. The mold flora has been destroyed by nitric acid and the mobile phase can pass through the filter smoothly. Open the pressure relief valve, turn on the pump, adjust the flow rate to 1.0 ~ 3.0ml / min, rinse the filter with pure water for about 1 hour. The filter can be cleaned. Close the pressure relief valve and rinse with pure methanol for half an hour.
Third, when the self-test, why does the "tungsten lamp energy low" error sometimes occur?
Generally speaking, the reason is that there are light blocking in the system, the optical path is deviated, and the tungsten lamp power system or the tungsten lamp bulb is broken. At this time, first check whether the photometric room has a light-blocking material; open the detector light source chamber cover to check whether the xenon lamp is lit; if the xenon lamp is not lit, shut down, replace the new xenon lamp, and change the time, pay attention to the model; check æ°˜Lamp fuse, see if it is loose, oxidized, burned; if it is faulty, it should be replaced immediately; then restart and self-test; if the above fault still occurs, re-install the software and then perform self-test.
Fourth, there is a large pressure fluctuation, the flow is unstable, what should I do?
The reason for this is that there is foreign matter between the gem ball and the valve seat with air or check valve in the system, so that the two cannot be sealed. Pay attention to the amount of mobile phase in the treatment work, ensure that the stainless steel filter sinks into the bottom of the reservoir, avoid inhaling air, and the mobile phase should be fully degassed. If there is a foreign object between the check valve and the valve seat, remove the check valve and put it into the beaker containing acetone for ultrasonic cleaning.
Fifth, the liquid chromatograph peak area repeatability is not good how?
The main reason may be that the injection valve leaks, the needle is not in place, or the liquid volume is insufficient. For the first case, the injection valve gasket should be replaced during processing; for the second case, the needle is inserted to the end, and the sample solution must be quickly and smoothly switched from the LOAD state to the INJECT state to ensure the injection volume. accurate. In daily work, the maintenance of the liquid chromatograph is very important. If you are careful not to let the air enter the infusion system and the high pressure pump, the solution in the reservoir should be cleaned and replaced with a solution if it has not been used for a long time. After the chromatograph is finished, the buffer should be rinsed with pure water to prevent precipitation or deposition of inorganic salts. The pretreatment of the sample is also important. Any sample should be removed as much as possible, completely dissolved, and the contamination of the column should be minimized. Extend the service life of the column while avoiding the injection of the concentrated sample solution to prevent the residual liquid from clogging in the injection valve. The column is marked and the column for different analysis purposes should not be mixed.
6. What is the reason for the increase in column pressure in liquid chromatography?
There are many reasons for the increase in column pressure. It is generally caused by an abnormal space-bearing object in the column bed, which causes an increase in fluid resistance. For example, a buffer salt such as ammonium acetate or the like is deposited in the column, or the sample is contaminated and deposited. For the first case, the treatment should first use 40~50 °C pure water, and the column should be flushed at a low speed. After the column pressure is gradually decreased, the flow rate is increased accordingly. After the column pressure is greatly reduced, it is rinsed with normal temperature pure water. The column was then rinsed with pure methanol for 30 minutes; for the second case, the contaminated C18 column was deposited by the deposition of the sample, and the column was rinsed back with pure water, then replaced with methanol, followed by methanol + isopropanol (4+6). Rinse the column (depending on the contamination of the sample), rinse with methanol, rinse with pure water, and finally rinse the column for more than 30 minutes.
(Content Source Instrument Network)
YT-T15
YT-T15
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