(1) for safety reasons
(2) the accuracy, reliability and repeatability of the experimental results
l Standardized operation throughout the entire experimental process:
① Preparation for the experiment. Doing experiments should be pre-arranged and planned. First of all, we need to consult the literature, the formulation of the experimental program, followed by the preparation of drugs and instruments used. Attention to the use of drugs (in advance to the basic information of the drug query completely, including melting and boiling point, solubility, toxicity? How to dispose after use, etc.) laboratory availability, location? What glass instruments might be used in this experiment? Do you have all these glass instruments in the lab? Are there enough of them? Are they clean? Do they need to be dried? Note! Find all the medicines and instruments in advance and place them in a fixed location for backup. For some communal experimental instruments, to be negotiated in advance to solve the use.
② Experimental process. Before the use of glass instruments, check again whether there is no damage. According to the experimental design to take drugs, start the experiment. Experimental process, people can not leave the operation site for a long time, especially the heating temperature of the experiment. Observe the phenomenon of the experimental process, and timely record, and according to the phenomenon of timely adjustment of their experimental program.
③ After the end of the experiment, deal with the experiment in time. If it is indeed too late to deal with, to add labels, so as not to be confused with other people's samples or accidentally poured by others, and in the experimental record book to write a truthful account of the situation. Pay attention to the tidiness of the experimental table, the cleaning of glass instruments, and timely drying. Especially some common instruments, don't occupy them for a long time without cleaning or washing them in time. Public drugs should be returned to the place in a timely manner after use.
④ Analysis and summary of the results of the experiment. After the end of the experiment, timely analysis of the results of the experiment, such as encountering problems that can not be solved by themselves, can be experienced brothers and sisters to ask for advice, and still can not be properly solved, timely consultation with the instructor, planning the next step of the experiment. Regularly summarize the experimental results at a stage, so that it is easy to find problems, and can summarize the law, conducive to the next experiment.
1. Use of ultrasonic waves
Function of ultrasonic waves: accelerate the dissolution
Cleaning of the instrument
Ultrasonic degassing Degassing of air bubbles in the solvent, so that the baseline is smooth during HPLC detection.
Precautions:
① First of all, check whether the bottle is broken, the bottle should be placed in the ultrasonic smooth, lest the liquid pour out.
② Ultrasonic water depth should be appropriate, should not be used for a long time, pay attention to the stop in the middle.
③ Regular replacement of water.
2. The use of thermostatic water bath:
① Heating water bath water to cover the material
② bottle to match the condenser tube
③ condenser water problems: the water flow is appropriate, the firmness of the rubber tube, check whether there is aging? Size can be matched? Whether connected to the wrong?
④ Placement of the downpipe, pay attention to be sure to put in the sink, and finally align the downpipe mouth. Be sure to put stable, do not let the water leak to the floor, do not!
3. rotary evaporator
(concentration): mainly used for continuous distillation of a large number of volatile solvents under reduced pressure. Must be connected with the circulating water pump (right)
Rotary evaporator and circulating water pump of the various interfaces of the grinding, pay attention to lubrication and sealing, vacuum tube regular inspection and replacement, otherwise the vacuum does not meet the requirements.
If the vacuum can not pump up or the vacuum degree becomes small need to check:
(1) the joints, interfaces are sealed
(2) sealing ring, sealing surface is too much wear and tear, but also whether it is effective
(3) the spindle and the sealing ring between the vacuum grease is coated
(4) the vacuum pump and its skin tube is leaking
(5) the glass parts are cracked, broken, and the vacuum pipe is leaking
(5) the rotary evaporator and the circulating water pump. Whether the glass parts have cracks, broken, damaged phenomenon
The concentration process needs to pay attention to the following issues:
① Don't load too much, the requirement is not more than 1/2, otherwise it is easy to boiled and contaminated.
② Do not turn too fast at the beginning, otherwise the vacuum can not reach the bottle is easy to fall off.
③ Concentration process is generally the first vacuum and then warming, and pay attention to timely outgassing to reduce the boiling. Alcohol and water mixture in the concentration of especially easy to boil
④ concentration is completed off the pump, pay attention to the first unloading vacuum, and then turn off the power supply of the pump, do not reverse the order caused by the reverse suction. When unloading the vacuum, pay attention to protect the bottles (especially large, heavy bottles) not to fall into the water. Circulating water pump generally have two pumping port, so shut down the pump to observe whether the other pumping port is in use? Remove the bottle should also pay attention to the height of the water bath, not appropriate to lower the water level first, otherwise the bottle mouth dipped in water or bottle and water bath pot collision, damage to the glass bottle contamination of the sample.
⑤ Pay attention to the replacement of water in the water bath as well as the replacement of water in the circulating water pump. It is recommended that the water in the circulating pump be replaced once a week, and the period of water replacement should be shorter when it is used more frequently. Or connect the condensate outlet with the circulating water pump to realize the timely replacement of water in the circulating water pump.
4. The use of pumping device: connected to the circulating water pump
HPLC solvent filtration and degassing: filtration to remove some particulate impurities, the use of microporous filter membrane, pore size 0.45um and 0.22um, divided into aqueous phase membrane and oil phase membrane.
Precautions for decompression filtration of solvents? Check if there is any damage to the filtration bottle first. Can you align the bottles so that there is no leakage? Can't suck backward? It is strictly prohibited to leave the work site for a long time when pumping solvents, which will make the vacuum pump empty for a long time and shorten its life.
5. The use of electronic balance
① Precision instruments, leveling, is strictly prohibited to move.
② Note the range of the balance. Generally there is a max, min on the balance.
③ Pay attention to clean. Solid samples with weighing paper, be careful not to spill on the weighing pan, especially some corrosive samples, weighing especially careful. If you want to spill, turn off the balance power, gently remove the tray, with soft paper in time to spill to the crevice of the items cleaned off, if necessary, with a cotton ball dipped in anhydrous ethanol wipe. Be especially careful when weighing liquid samples, and be sure not to spill onto the tray, the crevices of the opening and closing doors, or the liquid crystal display. If corrosion, it will cause the balance to weigh inaccurately, the door can not be closed or it is difficult to open and close the door. After the balance has been used for a period of time, it should be calibrated with the calibration weights that come with it to ensure accurate weighing.
④Clean up after use. This cleanup includes discarded weighing paper, disposal of spills around the balance, and cleanup of remaining items on the medicine spoon. If necessary, the spoon should be cleaned, inorganic salts can be rinsed with water basically, organic drugs with the appropriate organic solvent washing, the spoon washed in time, put back to the original position.
6. Oven use
Drying samples: ① Pay attention to the temperature setting, for the baked samples have special requirements, easy to high-temperature deterioration of the samples, you must wait for the oven temperature stabilization and then put. Otherwise, in the oven temperature, there will be part of the time more than the set temperature 5 ~ 10 degrees.
② Try to bake samples during the day, avoid overnight. High-temperature baking samples should pay attention to timely check whether there are abnormalities.
③ To use petri dishes or beakers to contain, the sample is strictly prohibited overfilled, pay attention to put the level, especially some of the extract or viscous material.
Drying instruments: ① clean glass instruments, first drained most of the water, and then sent to the oven for drying.
② remove rubber bands, rubber plugs, etc., as far as possible to remove the labeling paper
③ first full of the upper layer, and then put the lower layer. The lower layer of dry instruments, must first be removed, and then to the upper layer of stacked wet instruments, otherwise the lower layer of dry instruments are prone to wet instruments of water droplets cracked.
7. Reasonable use of the refrigerator
Use: to store some of the need for low-temperature refrigeration or freezing of medicines or personal samples, such as biological samples.
Storage of samples Note:
(1) do not just what drugs or samples to the refrigerator, (this is the wrong idea: samples exist in the refrigerator is easier to store than at room temperature, etc.) there is a need to store and then use. Arrangement of neat, smooth, do not want to randomly stacked by hand, the refrigerator door gently open and close, otherwise the large vibration easy door cabinets stored on the liquid samples tilted or tilted out, contamination of the refrigerator or other people's samples.
(2) Remember to store samples labeled, indicating why the sample? No. and what is contained? Especially for personal production of important samples, be sure to note that the labeling paper is best wrapped with plastic tape, otherwise the samples repeated freezing and thawing prone to cause labeling, blurred handwriting and so on.
(3) If the samples are sensitive to moisture, carefully wrap the seal of the bottle with waterproof tape to insulate it from water vapor as much as possible.
(4) Personal samples are regularly cleaned up, and useless samples are disposed of in a timely manner. For other people's samples, do not take out without permission, moving, arbitrary disposal, etc..