What problems should be paid attention to to to ensure the correctness of the identification results of a natural drug?

To ensure the correctness of the identification results of a natural drug, what problems should be paid attention to

sufficient purity!

sufficiently high-resolution NMR

high-resolution MS!

some drugs need accurate crystal form

some drugs need accurate optical structure (optical rotation) identification of chemical components of natural drugs

qualitative identification?

chemical qualitative analysis refers to the use of certain chemical reagents to produce special odor, color, precipitation or crystallization with certain chemical components in traditional Chinese medicine as a means to identify varieties of traditional Chinese medicine. The specific components of high-quality traditional Chinese medicine can also be used as one of the characteristics of quality evaluation. In the chemical qualitative analysis of traditional Chinese medicine, its extract, powder or slice can be used. For example, chemical reagents are directly added to the surface, slice or powder of traditional Chinese medicine, and the resulting crystals (observed by microscope) and special color reactions are observed; Slices or powder can also be placed on glass slides or filter paper, and corresponding reagents are dripped for direct observation; Take a proper amount of Chinese medicine powder in a small test tube, add a proper solvent to extract its chemical components, then drop the solution on a glass slide, filter paper or add it into a small test tube, and then drop a certain chemical reagent and observe its phenomenon; The sublimable components in traditional Chinese medicine were separated by micro-sublimation method, and the chemical reaction phenomena were observed by adding appropriate reagents. On the question of paternity test results ~ ~ ~ ~ ~

According to the technical specification of paternity test currently used in the industry, CPI is above 1, that is, RCP is above 99.99%, which supports biological paternity test.

So the conclusion of paternity test will support biological paternity. Or does not support biological paternity.

where is the accuracy?

Accuracy and inaccuracy are the limitations of current technology. What problems should be paid attention to in the experiment to make the dissolution determination accurate? (1) What operation steps should be paid attention to in the experiment to determine the accurate content of vitamin C? Answer: 1. When measuring the liquid, it must be accurate, and the line of sight must be equal to the lowest part of the concave liquid level when reading; 2. When titrating, we must control the titration speed, and don't drop too much 2,6 dichlorophenol indophenol solution at once, resulting in excessive titration. If this happens, how can we ensure the accuracy of the determination results of chlorophyll a concentration in water samples? What should we pay attention to?

There are many methods to determine chlorophyll a in phytoplankton, which can be divided into high performance liquid chromatography, fluorescence photometer and spectrophotometer according to all the instruments used. High performance liquid chromatography (HPLC) can accurately determine the content of various photosynthetic pigments, but it can not be used for rapid analysis of a large number of samples in the field because of expensive instruments and complicated analysis steps. Fluorophotometer can also accurately determine the content of chlorophyll a, especially the samples with low chlorophyll a content, but it is not conducive to the rapid analysis of various field samples because it is easily interfered by other pigments or pigment derivatives during the analysis. Therefore, the spectrophotometer method has become the most commonly used method to determine the chlorophyll a content of phytoplankton. What problems should be paid attention to when using natural gas

1. What are the requirements for the environment when using natural gas?

the gas device should be set in the kitchen with fire resistance and fire prevention efficiency. Flammable and explosive articles shall not be piled up in the room, and there shall be no second fire source. It is necessary to ensure ventilation in the gas environment.

2. What are the components of natural gas and combustion waste gas and their harm to human body?

(1) carbon dioxide (CO2)

carbon dioxide is odorless and sour colorless gas, which is the product of natural gas combustion. Carbon dioxide has an anesthetic effect, which can * * * face plate and mucous membrane. The content of carbon dioxide in fresh air is .4%, which is harmless to human body. When the combustion exhaust gas fills the uncompensated fresh air in the room, the indoor carbon dioxide increases and the oxygen content decreases relatively, which will cause people to suffocate.

(2) methane (CH4)

The main component of natural gas is methane. Methane is harmless to human physiology, but it has asphyxiating effect. When its concentration in the air reaches 1%, it can suffocate people. When the content of natural gas (methane) in the air reaches 5-15%, it will explode when it meets the fire source.

3. Why can't gas pipelines and facilities be closed?

natural gas pipelines, valves, meters and other facilities need regular inspection and regular maintenance. If these facilities are closed, it will bring inconvenience to the inspection and maintenance. If the gas leakage accident cannot be found in time, the natural gas in the closed environment will be gathered, which will easily lead to fire and explosion accidents.

4. What are the rules for connecting the hoses of gas appliances?

the hose is used for a long time, and it is easy to age, leak and cause accidents, so the hose should be used as short as possible. General rules should not be more than 2 meters, and can't go through walls. Check the rubber hose from time to time, and replace it with a new one in time if it is aging.

5. how to check the air leakage of gas facilities?

When it is suspected that the gas pipes and valves are leaking, the following steps can be taken:

(1) Turn off all the gas appliances (such as stoves and water heaters), and observe the last digit of the gas meter. After careful observation for a long time, there should be no movement.

(2) Brush the valves, pipes, joints, etc. with soapy water or high-foaming washing powder water. If there is bubbling, there will be air leakage points.

(3) close the air inlet valve in front of the gas meter and ask the maintenance personnel of the natural gas company to repair it.

(4) it is forbidden to use naked flame to check the leakage.

6. how to deal with a large amount of natural gas leakage?

after receiving the notice of gas stoppage or finding sudden gas stoppage, the valve of gas consumption device should be closed to prevent unburned natural gas from leaking into the room after gas inflow. In addition, the aging and damage of the device may cause natural gas leakage.

when finding a large amount of natural gas leaking indoors, we should first cut off the gas source, open doors and windows to reduce the concentration of natural gas in the air, and then notify the maintenance personnel of the natural gas company to deal with it. Never use gas appliances, or even turn on or off electric lights, to prevent the possibility of sparks in the room, so as to prevent the leakage gas from burning and exploding.

7. How to rescue poisoned personnel?

when someone is found to be poisoned by natural gas, the gas source should be turned off first, the doors and windows should be opened for ventilation, the poisoned person should be quickly lifted away from the poisoned environment, artificial respiration should be carried out, and the person should be sent to the hospital for rescue in time.

The symptoms of natural gas poisoning are as follows:

Mild: dizziness and swelling of temples.

moderate: dizziness, eye pain, nausea, weakness of limbs, and restlessness.

severe: coma, dyspnea, shock, anoxia and asphyxia.

Repeated chronic poisoning will make people's health worse and their memory decline.

8. Why can't gas pipelines and facilities be changed arbitrarily after unified installation and acceptance?

gas pipelines and devices are designed, installed and inspected in strict accordance with relevant national technical specifications before they are put into use, so as to ensure the tightness and safety of gas supply and use facilities. Without on-site investigation, rectification and inspection by professionals of natural gas company, users move the installation location of pipelines and facilities privately, and their tightness, safety and durability are not reliably guaranteed. Therefore, if the user's gas environment changes or needs to rectify the natural gas facilities, he must apply to the natural gas company according to the procedure for unified rectification and acceptance. Users are not allowed to move natural gas facilities, expand the scope of gas use and change the nature of gas use without authorization.

9. what should I pay attention to when using natural gas?

(1) When cooking and boiling water, do not fill the pots and pans with soup and water, so as to prevent the soup from boiling and overflowing, dousing the flames and causing air leakage.

(2) When there is wind, the flame may be blown out by the wind, resulting in air leakage, so a circle should be made to prevent the wind.

(3) gas should not be separated from people, so as to prevent a large amount of natural gas from gushing out due to the above two reasons, which can't be handled in time and cause accidents.

(4) educate children not to play with the natural gas switch, so as not to damage or forget to turn it off, causing air leakage and accidents.

(5) Close the stove valve immediately after three meals a day. Before going to bed at night, before going out or after use, the facilities such as the switch of natural gas stove and the block valve behind the table should be carefully inspected. Open and close the day valve of natural gas meter. If you need to go out for a long time, all the front and rear valves of natural gas meter should be closed.

1. What should I pay attention to when using a gas water heater?

(1) Users who need to install water heaters must go through the formalities at the natural gas company and are not allowed to install them themselves.

(2) The selected water heater must meet the national GB6932-86 domestic gas-fired quick water heater standard. The type of gas used in the famous brand of water heater must be consistent with the airflow.

(3) The water heater must be installed in a well-ventilated kitchen or a separate room. When conditions are not available, it can also be installed in a well-ventilated aisle. It is strictly forbidden to install it in a bedroom, bathroom or toilet.

(4) The height of the room where the water heater is installed should be more than 2.5 meters, and its room volume is generally not less than 18m3, but it can be handled as appropriate according to the ventilation condition of the room.

(5) The room where the in-line water heater is installed must have good natural ventilation, and the upper part of the room should be provided with an exhaust fan or louver that goes straight to the outside, and the lower part should be provided with a louver with an area of not less than .2m2 or a gap with a height of not less than 3mm between the door and the ground.

(6) The flue water heater must be equipped with a flue and an anti-downdraft device, and the smoke extraction force of the flue should be not less than 3Pa (when there is no instrument, the paper strip or smoke can be used to visually check that the smoke extraction force should be available). The room where the flue water heater is installed must have good natural ventilation, and the lower part of the door should be provided with shutters with an area of not less than .2m2 or a gap with a height of not less than 3mm between the door and the ground.

(7) Only after the small fire burner (long flame) is ignited can the water inlet valve be opened and the main fire burner be ignited. If the water inlet valve is opened before the long flame is ignited (that is, the water heater linkage valve is opened), natural gas leakage will occur. Therefore, when igniting, there will be an explosion sound, and if the time is too long, it will easily cause an explosion accident.

(8) When the water inlet valve is closed during intermittent use, people should not stand under the shower nozzle to avoid scalding.

(9) When using the water heater, it must be operated in strict accordance with the operating instructions of the water heater and relevant regulations on safe gas use, and the bathing time should not exceed 2 minutes, and the bathroom should be well ventilated. It is forbidden to use oxygen-consuming gas appliances for heating at the same time.

(1) When the hot water valve of the water heater is turned off, if the main burner is still burning, the gas valve should be turned off quickly, and it should be repaired in time after it is stopped. When air leakage or water leakage is found, it should be stopped, and the above abnormal conditions should be promptly notified to the maintenance service department of the natural gas company for repair. Unauthorized disassembly and repair is strictly prohibited.

(11) maintain the water heater every year, and operate it in strict accordance with the instruction manual of the water heater.

11. How to save gas?

As a human resource, everyone has the obligation to save gas.

(1) using efficient and energy-saving gas devices is an important measure to save gas.

(2) When the natural gas burns, the flame is red and yellow, which means lack of oxygen, and the phenomenon of "off-fire" means that there is too much air. At this time, the air door of the cooker can be adjusted appropriately, and when the flame is purple and blue, it means full combustion.

(3) When cooking, you should prepare the food to be cooked before lighting it, so as to avoid burning an "empty stove". If you cook soup or stew, you should boil it with a strong fire first. Just turn down the fire and keep the pot boiling without overflowing, but you must turn off the fire when leaving people.

(4) When cooking, the size of the fire can be determined according to the size of the pot, and it is best that the flame distribution area is level with the bottom of the pot.

(5) It is best not to use steaming when cooking, and the steaming time is three times that of stewing rice.

(6) The water stains on the surface of the pot and kettle to be burned should be wiped dry before being put on the stove, so that heat energy can be transmitted into the pot as soon as possible and gas can be saved.

(7) If the flame is shaken by the wind, a thin iron sheet can be used as a "windshield", which can ensure the concentration of firepower and save gas. What problems should be paid attention to when choosing a career correctly?

What problems should be paid attention to when choosing a career correctly:

1. Determining life goals is a prerequisite for choosing a job. Ask yourself first what kind of life you want to live and how you want to live. For example, you are full of enthusiasm and ambition, like to accept new things and a challenging life, but you choose to work in a leisure institution like a nursing home. Then your daily work has become a painful tug-of-war between your ideal and reality, and the results can only be two: First, you compromise, your enthusiasm is gradually worn away, your ambition is weakened a little, and slowly, you become lifeless. Second, you can't get used to this kind of life in the end. After a complicated and long-term psychological struggle, you finally choose to continue fighting for your ideals or choose the life you want. Cruelly, it is unknown whether you can adapt to the fast-paced and competitive society by then. Of course, it's not that the institution is bad, the key is whether it suits you or not, and whether that kind of life is what you want. Therefore, never choose a job for the sake of comfort and stability and a good job in the eyes of others. When you choose a job, first of all, it must be because the job itself attracts you, and you love the life style and life state brought by this job.

2. Don't blindly pursue economic value. Choosing a job depends on the added value it can bring you, not just the salary. Of course, salary is the material condition to guarantee our living standard, but this is only for the current situation. For the future life, can a higher salary bring security? The answer is of course no, after all, the relatively high salary is limited after all, and it can't provide guarantee for your future life. Therefore, it is ability, not money, that can guarantee your future living standard. To get real protection, we should not rely on saving money, but on increasing the reserve of ability. If your ability reserve is improved, even if you want to leave your post and company due to various changes, you can find a new job immediately and continue to protect your life in a new environment. For example, there is a job with a monthly salary of 5, yuan and a job with a monthly salary of 8, yuan. At first glance, many people will not hesitate to choose the latter, but if the job with a monthly salary of 5, yuan has higher added value and can improve their ability, then the actual value of these two jobs has changed 18 degrees. Therefore, we must pay attention to the growth space that your work can bring you, that is, to see "real value."

3. Don't work hard alone, but choose your work objects. You should choose who to do it with. People will carefully choose wedding objects, but in the face of the choice of work objects, it seems that the degree of attention is far from enough. In fact, the choice of work objects is very important. A person's time with work objects is definitely not much less than that with wedding objects. For such a partner who needs to get along for a long time, if he is not a like-minded person, it may be difficult to go long.