Operating Regulations of Laboratory Glass Apparatus

Update:12-11-2020
Summary:

1. Purpose Establish a standard operating procedure for […]

1. Purpose

Establish a standard operating procedure for the use and cleaning of glass instruments to standardize the operating process.

2. Duties

The quality department QC is responsible for the drafting of this document, and the quality department and QC inspectors are responsible for the implementation of this standard.

3. Scope

This standard applies to the use and cleaning of glass instruments.

4. Content

4.1 Measuring Instruments

4.1.1 The glass measuring device cannot be heated and heated, and cannot store concentrated acid or alkali. It should be used in accordance with relevant regulations.

4.1.2 Measuring cylinder and measuring cup are used to measure solutions with inaccurate concentration and volume requirements. When reading, the line of sight should be kept level with the lowest part of the concave surface of the solution in the measuring cylinder (or measuring cup).

4.1.3 Volumetric flasks are used to prepare solutions with accurate concentration and volume requirements or for quantitative dilution of solutions. The bottle stopper should be matched with good airtightness. Check if it leaks before use. When preparing or diluting the solution, when the solution is close to the marking line, use a dropper to slowly drip to the concave surface and the marking line Tangent. Volumetric flasks cannot store solutions for a long time, especially alkaline solutions.

4.1.4 burette is a more precise instrument used in titration analysis, which is used to measure the volume of solution used in titration. Constant burette can be divided into acid type and basic type. Before use, check whether there is water leakage. In order to ensure that the concentration of the standard solution into the burette is not diluted, the standard solution should be washed three times before loading the standard solution. After the standard solution is filled with the burette, the bubbles in the lower part of the burette should be drained. When reading, the line of sight should be level with the concave surface of the solution.
4.1.5 pipette is used to transfer a certain volume of liquid accurately. The constant pipette has a graduated pipette and a plump pipette. When in use, the cleaned pipette should be washed three times with aspirate. When discharging, the liquid should flow out naturally. After flowing, keep the pipette vertical and the container tilted 45. If there is no "blow" on the pipette, it is not necessary to blow out the liquid remaining at the tip of the pipette, but when there is a "blow" on the pipette, the liquid remaining on the tip of the pipette should be blown out.
4.2. The washing of the instrument requires not only removing dirt, but also not introducing any interfering ions.
4.2.1 generally, the cleanliness can be checked by the following method: add water to the vessel, and after the water is poured out, a layer of water film will be evenly attached to the vessel wall, which will neither gather into water drops nor flow down into streams, which is called washing.
4.2.2 the instrument should be washed before use, after the experiment and after the storage exceeds the specified time limit.
4.2.3 wash with tap water before washing. The measuring cylinder and measuring cup can be injected into detergent (synthetic detergent or detergent solution), slightly shaking or brush with brush, then rinsing to tap water without foam, after the water is dripped from the volumetric flask, burette and pipette, add a small amount of chromic acid lotion, soak for 4-6 hours or overnight, pour out the lotion (wash it back in the bottle, recycle it or pour it into the waste liquid wash cylinder), and tap water. Wash it clean (it is not allowed to wash the instrument containing ether with chromic acid washing solution, which is easy to explode when the ether encounters the washing solution); finally, wash the instrument along the inner and outer walls with distilled water for 2-3 times.
4.2.4 put the cleaned instrument upside down on the filter paper, put it on a clean shelf or in a special cabinet, let it drip and drain naturally; use an electric blower to dry the instrument with cold air or hot air; or add a small amount of volatile organic solvent (ethanol, ether, etc.) for wetting and then pour it out, repeat for 3-5 times, and then let it evaporate naturally to dry or blow it to dry in the order of hot air and cold air Dry, this method can achieve the purpose of rapid drying, but pay attention to indoor ventilation, fire prevention, anti-virus, etc., organic solvents are expensive, only use this method in case of emergency.

5.1.1 the beaker is mainly used to prepare solution, boil, evaporate, concentrate solution, carry out chemical reaction and preparation of a small amount of substances. Asbestos mesh should be padded when heating; water bath, oil bath or sand bath can also be used. The content should not exceed 2 / 3 of the volume when heating, and the watch dish should be covered when adding hot corrosive liquid.
5.1.2 flasks are used for heating, boiling and chemical reactions between substances. When heating, asbestos mesh should be padded (round bottom flask can be directly heated), and the content should not exceed 2 / 3 of the volume. Flat bottomed flasks and round bottomed flasks are commonly used for solid-liquid reactions with more reactants, or liquid-liquid reactions and reactions requiring longer heating time. Check whether there are bubbles, cracks, nicks and uneven thickness before use.
The triangular flask is easy to shake during the reaction and is often used as a container in titration operation. The fixed iodine flask, also known as the flask with stopper, is mainly used in the determination of iodometry. The cork should be opened when heating to prevent the plug from flushing out or the bottle breaking. The stopper should be kept in the original configuration. If condenser is needed for distillation flask, the short neck thick mouth flask should be selected. When connecting the distillation flask and condenser, the branch pipe through the rubber plug should not be less than 4-5cm into the condenser. The multi port flasks are usually used to make gas or volatile substances and as heating vessels in distillation.
5.1.3 the test tube is often used for qualitative test, which is convenient for operation and observation. It can be heated by direct fire. When heating the content, it should not exceed 1 / 3 and not more than 1 / 2 when heating. When heating the solid substances in the test tube, the pipe orifice should be inclined downward to prevent the condensate from returning to the bottom of the test tube and breaking the test tube.
5.1.4 centrifugal tube is often used for precipitation separation in qualitative analysis and cannot be directly heated.
5.1.5 the colorimetric tube is mainly used to compare the color of the solution. For substances with low element content, it can be used for simple and rapid quantitative analysis by visual method. Do not heat when using. Keep the transparency of the tube wall, especially the tube bottom.
5.1.6 reagent bottle is used to contain reagent. Each reagent bottle must be labeled with the name, concentration and purity of the stored reagent. The cork and dropper are not interchangeable and should be kept as original. When using, the bottle stopper should be upside down on the table top; when using the dropper, do not inhale the solution into the rubber head, and do not place the dropper in other places.
5.1.7 weighing bottle is mainly used to weigh a certain mass of sample when using analytical balance, and it can also be used for drying sample. Usually to wash, dry, store in the dryer for use at any time. It is not allowed to heat directly with fire, the bottle cap can not be exchanged, and it can not be taken directly by hand during weighing. Gloves or clean paper should be worn.

5.2. When washing the instrument, not only the dirt should be removed, but also any interfering ions should not be introduced.
5.2.1 generally, the cleanliness can be checked by the following method: add water to the vessel, and after the water is poured out, a layer of water film will be evenly attached to the wall of the vessel, neither forming water droplets nor flowing down into streams, which is called washing.
5.2.2 the instrument should be washed before use, after the experiment and after the storage exceeds the specified time limit.
5.2.3 wash with drinking water before washing. Use a brush to dip in detergent (synthetic detergent or detergent solution) to brush the inside and outside of the instrument, and then wash it with water edge until it is cleaned; if the detergent can not be cleaned, drain the water in the instrument, add a small amount of chromic acid lotion into the instrument, and then turn it slowly and obliquely to wet the inner wall for several times. You can also soak it for 4-6 hours or overnight, and pour out the washing liquid (pour Recycle the washing solution bottle or pour it into the waste washing liquid collection bottle for unified treatment), and then rinse it with tap water; after that, wash it 2-3 times along the wall with distilled water.
5.2.4 the cleaned instrument shall be inverted in filter paper, clean shelf or special cabinet and allowed to drain naturally; the cleaned instrument shall be placed in an oven at 105-120 ℃ for 1-2 h. for thick wall instrument and solid glass stopper, the temperature shall be slowly increased. After drying, it is stored in special shelf, special kitchen or dryer. Put the cleaned instrument on the lamp flame and dry it directly. The test tube can be tilted with the nozzle downward and gradually baked from the tail to the mouth. When no water drops can be seen, the nozzle of the tube should be upward to exhaust the moisture. The beaker can be placed on the asbestos net and baked at a low fire. This method can be used in case of emergency.
5.3. The container should be stored in a clean environment with dust-proof device.
6. Other categories
6.1. All glass instruments shall be used according to their regulations.
6.1.1 funnel is mainly used for filtering operation and pouring liquid into small mouth container. It can filter hot solution, but can not be directly heated by fire.
6.1.2 the glass sand core filter is often matched with the filter bottle for vacuum filtration. Different substances can be filtered according to the size of the hole (the larger the number of filter pieces, the smaller the aperture). Attention should be paid to avoid the corrosion of alkali liquor and hydrofluoric acid. The filter bottle can withstand negative pressure and cannot be heated.
6.1.3 the dryer is mainly used to keep the articles dry, and can also be used to store small-sized and valuable instruments that are moisture-proof, weighing bottles and crucibles that have been dried. When using, a thin layer of Vaseline should be applied along the edge to avoid air leakage. When opening, the top cover should be moved slowly to the horizontal direction.
6.1.4 after the dropper is taken out of the reagent bottle, the rubber head shall be kept on the top and shall not be placed horizontally or obliquely to prevent the test solution in the burette from flowing into the rubber head, corroding the rubber head and contaminating the reagent. When dropping the reagent into the test tube or other containers with a dropper, it must be suspended above the mouth of the tube or container. It is absolutely forbidden to put the tip of the dropper into the tube or container to prevent the end of the tube from touching the wall and adhering to other substances.

6.1.5 the condensing tube, connecting pipe and fractionating tube are used together with other instruments for condensation and fractionation operation. Pay attention to the tightness of internal and external grinding mouth when using, and carefully operate the installation and disassembly in sequence.
6.1.6 evaporating dish is mainly used for evaporation, concentration and crystallization of solution. It should be cleaned and dried at ordinary times,
6.2. In the laboratory work, there are higher requirements for the cleaning of the instrument, which not only requires the removal of dirt, but also requires that no interfering ions can be introduced.
6.2.1 generally, the cleanliness can be checked according to the following method: add water into the container, and after the water is poured out, a layer of water film will be evenly attached on the wall of the vessel, which will neither gather into water drops nor flow down into streams, which is called washing.
6.2.2 before use and after the experiment, the glassware stored beyond the specified period shall be washed.
6.2.3 when washing glass instruments, first wash them with drinking water. Except for glass core leakers, other instruments can be washed with detergent (synthetic detergent or washing powder solution) (glass core leakers and other instruments that cannot be cleaned with detergent should be washed with a small amount of chromic acid lotion until they are clean); * *, and then wash 2-3 times along the inner and outer walls with distilled water.
6.2.4 place the cleaned instrument in an oven of 60-80 ℃ (the evaporating dish can be 105-120 ℃) to dry, or invert the cleaned instrument on the filter paper, clean shelf or special cabinet, and let it drip and drain naturally.
6.3 glass instruments should be stored in a clean and dustproof environment. Clean instruments should be washed again after a certain period of storage. Store in a dryer for ready use.

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