1, bubble overflow
There are bubbles in the mobile phase, the pump is turned off, the pressure relief valve is opened, the purg button is turned on, the degas is cleaned, the bubbles are continuously ejected from the filter, and the mobile phase enters the mobile phase. No matter how many times the purge button is turned on, the continuously generated bubbles cannot be removed. 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. The buffer is difficult to smoothly pass through the filter, and the air enters the filter under the pressure of the pump. Mobile phase. The treatment 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. The internal 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.
2, peak area repeatability is not good
(1) The injection valve leaks.
(2) The sample needle is not in place.
(3) The liquid volume is insufficient. The injection valve gasket is replaced for the case of *; 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 is 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.
3, high column pressure reasons
(1) A buffer salt such as ammonium acetate or the like is deposited in the column.
(2) Sample contamination deposition. For the case of *, first use 40 ~ 50 °C pure water, the column is washed forward at 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, then pure methanol. Rinse the column for 30 minutes; for the second case, contaminate the C18 column by deposition of the sample, and rinse the column back with pure water, then switch to methanol wash, then rinse the column with methanol + isopropanol (4+6) ( The length of the rinsing time is determined by the contamination of the sample. It is then rinsed with methanol and then rinsed with pure water. After the methanol rinse, the column is flushed for more than 30 minutes.
4, no pressure indication, no liquid flow
(1) The pump seal gasket is worn.
(2) A large amount of air bubbles enter the pump body. Treatment For the case of *, replace the gasket; for the second case, use a 50ml glass syringe to help extract air at the pump outlet while the pump is acting.
5, pressure fluctuations, flow instability
Cause There is a 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.
6, the peak is not good, peak fork
(1) The column is contaminated.
(2) The stigma packing collapses. For the case of *, 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, then rinse with pure water, and then rinse the column 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.
Emulsions are one of the most commonly used formulations in cosmetics, ranging from thin fluids to thick creams. Therefore, the selection of emulsifier for emulsion cosmetics is of great significance to the research, production, preservation and use of cosmetics.
The function of emulsifier in skin care products is really too important. Without emulsifier, most formulas cannot exist, and many active ingredients cannot be added to the formula.
In skin care products, emulsifier has two main functions: emulsifying and dispersing oil and active ingredients in the formula, providing special skin sensation and rheological characteristics.
Luxury skin care products usually take Xanthan Gum, AGAR powder, gelatin, carrageenan or glycerin monostearate as the Emulsifying Agent.
Our company provides high quality and purity natural Emulsifying agents, which includes Xanthan Gum, AGAR powder, gelatin, carrageenan and glycerin monostearate etc. A custom formula is also available if you would like to have your unique solution.
Emulsifying Agent,Oil-In-Water Emulsifier,Food Emulsifying Agent,Emulsifier Oil Additive Agent
Allied Extracts Solutions , https://www.alliedadditives.com