In the process of using copper alloy testing instruments, the measured results have large errors or no results at all. In the case of eliminating the problems of the instrument itself, the biggest problem that often occurs is the problem of chemical reagents, so let's talk about it. What problems should be paid attention to in chemical reagents?
1. A label should be affixed to the reagent bottle, indicating the name, concentration, and preparation date of the reagent, and a thin layer of wax should be applied to the outside of the label. Pay attention to protect the label of the reagent bottle during work to make it intact. If it is lost, it should be subsidized in time.
When dispensing reagents, solid reagents should be placed in easy-to-access wide-mouth bottles, and liquid reagents should be placed in easy-to-pour narrow-necked bottles or dropper bottles. Reagents that are easily decomposed when exposed to light, such as silver nitrate, should be placed in Brown reagent bottles, and kept in a dark place; reagent bottles containing lye should use rubber stoppers; familiar with the properties of common metal element analyzer chemical reagents, such as the concentration of commercially available acid and alkali, the solubility of reagents, organic solvents Boiling point, toxicity and chemical properties of reagents, etc.
2. Before taking reagents, read the label clearly. When taking it, if the top of the cork is flat. The bottle stopper can be placed upside down on the analysis table. If the top of the bottle stopper is not flat, the index finger and middle finger can be used to hold the bottle stopper or place it on a clean and dry watch glass. It is strictly forbidden to put the bottle stopper on the analysis table horizontally; for solid reagents Use a clean medicine spoon to take it. If the reagent is agglomerated, use a clean and dry thick glass rod or a special stainless steel spatula to mash it before taking it. After removing the reagent, the bottle stopper should be tightly closed immediately to prevent the wrong stopper from contaminating the reagent. The used medicine spoon and glass rod must be washed in time.
3. General solid reagents can be weighed on clean waxy paper. Solid reagents that are corrosive, strongly oxidizing or deliquescent should be weighed in a container after get off work, and must not be weighed with filter paper. If you take too much when weighing, you should pour the excess medicine into a designated container for others to use, and never pour it back into the reagent bottle; when measuring liquid reagents with a graduated cylinder in the laboratory, the left-handed measuring cylinder should The thumb indicates the scale of the required volume, hold the reagent bottle in the right hand, and pay attention to touching the reagent bottle into the graduated cylinder to prevent droplets from flowing down the outer wall of the reagent bottle. Then erect the reagent bottle, close the cork tightly, and put it back in place with the label facing outward. When reading the scale, the line of sight and the liquid level should be on the same level. If too much liquid reagent is poured out carefully, it can only be discarded or poured into a designated container for others to use.
4. Use the dropper to drop the reagent into the test tube, use your left hand to hold the test tube vertically, the thumb and index finger of the right hand to clamp the rubber tip of the dropper, and the middle and ring fingers to clamp the dropper rubber tip and the connection point of the off-duty tube. Take the dropper vertically or obliquely, and insert it directly above the test tube mouth. The distance between the dropper and the test tube is about 2-3mm, and then squeeze the rubber tip to drop the reagent into the test tube. The dropper cannot be inserted into the test tube. Do not touch the inner wall of the test tube, otherwise, the mouth of the dropper will easily be stained with other solutions on the inner wall of the test tube. If the dropper is put back into the original solution bottle, the reagent in the dropper bottle will be contaminated; take out a small amount of reagent from the dropper bottle When, first lift the dropper to keep the nozzle away from the liquid surface, pinch the rubber tip on the upper part of the dropper with your fingers to drive out the air in the dropper, then put the dropper into the dropper bottle, put your finger on the surface, and inhale the reagent , Then lift the dropper and drop the reagent into the test tube or other container.