In the analysis, the washing glass instrument is not only a must do the preparation work before the experiment, but also a technical work. The washing of the instrument is in compliance with the requirements, the accuracy and precision of the test results have an impact on the accuracy and precision of the test results. Different analysis work has different instrument cleaning requirements, we use the general quantitative chemical analysis as the main method of washing equipment.

(1) clean agents and the range of use

The most commonly used cleaning agents are soap, soap solution (special products), washing powder, detergent powder, lotion, organic solvents, etc..

Soap, liquid soap, washing powder, decontamination powder for can brush direct scrub instruments, such as beakers, triangle and reagent bottle; a lotion for inconvenience for cleaning brush instruments, such as the burette pipette, volumetric flask, distillation and other special shape of the instrument, and can also be used to wash long unused cups, dishes and utensils, brush scaling. With the washing apparatus, is the use of the solution itself and dirt from the role of chemical reaction, the removal of dirt. Hence the need for full function of soaking a chance; organic solvent is the dirt is a certain types of greasy, while the use of organic solvents to dissolve the grease wash in addition to, or with the help of some organic solvents and mixed water and play fast particularity, rinse with water instrument will not wash. Such as toluene, xylene, gasoline and other can wash the grease, alcohol, ether, acetone can be the instrument just wash with water rinse.

(two) preparation of the washing liquid and the use of the matters needing attention in the detergent solution for short, according to different requirements, there are a variety of different solutions. The more commonly used are introduced as follows.

Strong oxidant lotion acid oxidant lotion is with potassium dichromate (K2Cr2O7) and sulfuric acid (H2SO4). K2Cr2O7 in acidic solution, has strong oxidation ability, less corrosion of the glass instrument ps.. So this lotion is widely used in the laboratory. Formulated concentrations vary, from 5~12% to a variety of concentrations are. Preparation method of roughly the same: take a certain amount of K2Cr2O7 (industrial products), with about 1 ~ 2 times of water, heating, dissolving, slightly cold, industrial concentrated H2SO4 required volume slowly adding K2Cr2O7 solution (do not will be water or solution by adding H2SO4), side down side by glass rod stirring, and careful not to spill, mixed evenly, as soon as after cooling into lotion bottle of spare. The newly formulated lotion is reddish brown, with strong oxidation ability. When washing with long into dark green, which means no oxidation stress washing lotion.

For example, the preparation of 12% lotion 500mL. Take 60 grams of industrial products of K2Cr2O7 placed in 100 ml of water (water amount is not fixed, in order to be able to dissolve), heating, dissolving, cooling, slowly adding concentrated H2SO4340mL, while kabe stirring, cold after bottling standby.

This kind of lotion in use should pay attention to can not be splashed on the body, in order to prevent burn broken clothes and damage the skin. Pour lotion to wash instrument, should make the instrument Biquan pause again after weeks of immersion into the lotion bottle. First with a small amount of water washing instrument just after immersion, don't waste water inverted in the water and sewer, long will the sewer of the pool and corrosion, should be inverted in the waste liquid in the cylinder cylinder full inverted in the garbage, if no waste liquid cylinder, but age literacy life concept of immortality ah hormone conversation into a pool of water, to edge down side by a lot of water flushing.

2 basic Lotion

An instrument used to wash oil and dirt, using this lotion for a long time (24 hours or more), or by boiling. From the alkali solution for the instrument, to wear latex gloves, so as not to burn the skin.

Commonly used alkali lotion: (Na2CO3 solution of sodium carbonate, sodium carbonate), sodium bicarbonate (Na2HCO3, baking soda), sodium phosphate (Na3PO4, trisodium phosphate) liquid, hydrogen phosphate disodium (Na2HPO4 solution).

3 basic Potassium Permanganate Lotion

Use alkaline Potassium Permanganate as lotion, slow, suitable for washing oil containers. Method: take the Potassium Permanganate (KMnO4) 4 grams and a small amount of water dissolved, adding 10% sodium hydroxide (NaOH) 100mL.

4 pure soda acid lotion

According to the nature of the vessel dirt, direct use of concentrated sulfuric acid (HCL) or concentrated sulfuric acid (H2SO4), concentrated nitric acid (HNO3) immersion or immersion cooking utensils (temperature should not be too high, no person strong acid volatile stimulation). Soda wash the immersion of more than 10% of the concentrated caustic soda (NaOH), potassium hydroxide (KOH) or sodium carbonate (Na2CO3) solution or soaking and cooking utensils (boiling).

5 organic solvents

With fat dirt, the vessel can with gasoline, toluene, xylene, acetone, ethanol, chloroform, ether and other organic solvents scrub or immersion. But with organic solvents as a waste of large waste, can be used as a brush to wash the large instruments to use alkaline lotion. Cannot use small pieces of brush or special shape of the instrument before using the washing with organic solvents, such as in the piston hole, a pipette tip, tip of the burette, burette live jack, dropper, vials etc..

6 cleaning solution

The vessel for testing the carcinogenic chemical substances, in order to prevent damage to the human body, before washing should be used to destroy the decomposition of these carcinogenic substances have the effect of washing and removing liquid for immersion, and then wash.

Often used in food inspection decontamination liquid: 1% or 5% sodium hypochlorite (NaOCL), 20%HNO3 solution and 2%KMnO4 solution.

1% or 5%NaOCL solution on the destruction of aflatoxin. Using 1%NaOCL solution to soak the contaminated glass equipment for a long time or soak a moment with 5%NaOCL solution, you can achieve the role of the destruction of aflatoxin. Method: take bleaching powder 100 grams, 500 ml of water, stirring evenly and other industrial Na2CO3 80 grams of dissolved in 500ml warm water, then the two liquid mixing, stirring, clarification filtration, the filtrate containing NaOCl was 2.5%; if bleaching powder concentrate formulated, NaCO3 weight should be doubled, and the resultant solution concentration is about 5%. If you need 1%NaOCL solution, the above solution can be diluted in proportion.

20% HNO3 solution and 2% KMnO4 solution of benzo (a) pyrene have destructive effects, benzo (a) pyrene contaminated glass instrument can be used 20% HNO3 and immersed for 24 hours, removed after washed with tap water to residual acid, before washing. By benzene and (a) pyrene contaminated latex gloves and micro syringe and other available 2%KMnO4 solution soak for 2 hours, then wash.

(three) the steps and requirements of the washing glass apparatus

Constant washing apparatus

Washing equipment, should be the first hand wash with soap, so that the hand of the oil attached to the instrument, increase the difficulty of washing. Such as long-term storage of equipment with dust, first washed with water, and then by the requirements of the use of detergent or washing detergent. Such as with scouring powder, brush dipped in a small amount of detergent, instrument and brush again and again while water Chong Bian scrub to invisible to the naked eye decontamination powder, wash with running water 3 to 6 times, and then distilled water washed three times or more. A fine glass instrument should be clean, do not hang water for. If still can catch on the water, still need to wash. When washing with distilled water, the instrument should be washed with a smooth wall and fully shake, after being washed by distilled water, the indicator should be used as neutral.

2 for trace metal analysis of glass instruments, the use of 1:1~1:9HNO3 solution immersion, and then carry out regular washing.

3 when the fluorescence analysis, the glass instrument should avoid the use of washing powder washing (washing powder containing fluorescent whitening agent, will give the results of the analysis of the error).

4 Analysis of carcinogenic substances, should use the appropriate wash snack soak, then wash with normal methods.