Washing and drying of common glass instruments.

in the analysis work, washing glass instruments is not only a necessary pre-experimental preparation, but also a technical work. Whether the instrument is washed meets the requirements has an effect on the accuracy and precision of the test results. Different analytical work has different instrument washing requirements, we mainly introduce the washing method of the instrument based on general quantitative chemical analysis.
(i) Cleaners and range of use
the most commonly used cleaners are soap, soap liquid (special merchandise), washing powder, detergent, lotion,
organic
solvents, etc.
soap, soap liquid, laundry detergent, detergent, instruments that can be brushed directly with a brush, such as
Beaver
, triangular bottles,
reagents
bottles, etc., washing lotions are mostly used for instruments that are not convenient for brushing, such as
titer tube
, pipe pipe,
capacity bottle
, distillers and other special shapes of instruments, but also used to wash long-term use of cupware utensils and brush brush can not be used under the fouling.
washing equipment with lotion, is the use of lotion itself and dirt chemical reaction, the dirt removal.
So there is a need to soak a certain opportunity to fully function; organic solvents are for dirt belonging to a certain type of greasy, and with the help of organic solvents can dissolve the role of grease washed away, or with the help of some organic solvents can mix with water and play a fast speciality, rinse the instrument with water will not wash away. For example, toluene, xylene, gasoline, etc. can wash scale, alcohol, ether, acetone can be washed freshly washed with water instruments.
(ii) Precautions for the preparation and use of washing liquid
Washing liquid referred to as lotion, according to different requirements have a variety of different lotions . . . will be more commonly used several introductions as follows.
1. Strong acid oxidant lotion
strong acid oxidant lotion is made with heavy chromate (K2Cr2O7) and strong sulphuric acid (H2SO4). K2Cr2O7 in acidic solution, has a strong oxidation capacity, glass instruments and rarely erosion. Therefore, this lotion is most widely used in the laboratory.
the preparation of different concentrations, from 5 to 12% of the various concentrations have.
preparation method is about the same: take a certain amount of K2Cr2O7 (industrial products can be), first with about 1 to 2 times the water
heating
dissolved, slightly cooler, the industrial product H2SO4 required volume Slowly add K2Cr2O7 insoluble solution (do not add water or solution to H2SO4), side upside down with glass rod stirring, and pay attention not to spill out, mix evenly, after cooling, loaded into the washing lotion bottle spare.
newly made lotion is red-brown and has a strong oxidation capacity. When the lotion becomes black-green after a long time, it means that the lotion has no oxidation washing force.
e.g., the preparation of 12% lotion 500mL. Take 60 g industrial K2Cr2O7 in 100mL water (the addition of water is not fixed, to dissolve as a degree), heating dissolved, cooled, slowly added thick H2SO4340mL, side-by-side stirring, cold after bottling standby.
use of this lotion should be careful not to spill on the body, in order to prevent "burning" broken clothes and damage to the skin.
the washing lotion into the instrument to be washed, the instrument should be fully immersed after a short stop and then pour back into the lotion bottle. The first time with a small amount of water to rinse just washed the instrument, waste water do not pour in the pool and sewer, long-term corrosion of the pool and sewer, should be poured in the waste tank, tank full after pouring in the garbage, if there is no waste tank, the age-literate outlook on life immortal ah
hormones
talk into the pool, to use a large amount of water flushing.
2. Alkaline lotion
Alkaline lotion is used to wash oil-stained instruments, using this lotion for a long time (more than 24 hours) immersion method, or immersion method. When extracting the instrument from the alkali lotion, wear latex
gloves
avoid burning the skin.
commonly used alkali lotions are: sodium carbonate (Na2CO3, i.e. soda), sodium bicarbonate (Na2HCO3, soda), sodium phosphate (Na3PO4, trisodium phosphate) liquid, sodium phosphate (Na2HPO4) liquid, etc.
3.Alkaline potassium permanganate lotion
with alkaline potassium permanganate as a lotion, slow action, suitable for washing oily vessels. Displication: Take potassium permanganate (KMnO4) 4 grams plus a small amount of water dissolved, and then add 10% sodium hydroxide (NaOH) 100mL.
.