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Abstract: Measuring pipette is a gauge used to accurately move a certain volume of solution. A measuring pipette is a dispensing instrument used only to measure the volume of the solution it releases. It is a long, thin glass tube with an expanded part in the middle. The lower end of the nozzle, the upper end of the tube neck is engraved with a line, is the accurate volume of the mark.

1 Introduction

Common measuring pipettes have 5,10,25,50 ml and other specifications. The volume removed by the measuring pipette is usually accurate to 0.01 ml.

2. Steps

According to the volume and requirements of the solution to be moved, choose the appropriate size of the measuring pipette for use. The measuring pipette is generally used for accurate removal of the solution in titration analysis, and it is generally used when the reaction needs to control the amount of the test solution.

Inspection equipment

Check whether the nozzle and tip of the measuring pipette are damaged or not. If there is any damage, it cannot be used.

Clean the instrument

After rinsing with tap water, soak with chromic acid detergent.

The operation method is as follows:

Take the upper end of the measuring pipette in a suitable position with the right hand, index finger close to the upper mouth of the measuring pipette, middle finger and ring finger open and hold the outside of the measuring pipette, thumb in the middle of the middle finger and ring finger hold the inside of the measuring pipette, little finger naturally relax;

Hold the ear washing ball in the left hand and hold the clenched fist position. Hold the ear suction ball in the palm with the tip down, clench the ear suction ball and discharge the air in the ball. Insert the tip of the ear suction ball into or close to the top of the measuring pipette, pay attention to avoid air leakage.

Slowly loosen the left hand finger, the washing liquid slowly inhaled into the tube, until the scale above the part, remove the suction ear ball, quickly block the measuring pipette mouth with the right index finger, wait for a moment, the washing liquid back to the original bottle. Rinse the inner and outer walls of the measuring pipette with running water until water drops are not hanging, then wash with distilled water for 3 times, control the dry water for reserve.

Draw solution

Shake to solution absorption, will stay pour a small part of the solution absorption in a small beaker, wash and dry with a measuring pipette tip of filter will be cleaned inside and outside the moisture blot, extract solution and insert small beaker and when suction to 1/3 of the measuring pipette capacity, with right index finger hold the nozzle immediately, remove and a horizontal and turn the measuring pipette, make the solution flows through the pipe wall, Dump the solution from the lower tip into the waste liquid cup. In this way, the solution can be absorbed after 3-4 times of moistening and washing.

Insert the measuring pipette that has been moisten and washed with the liquid to be sucked into a place 1 ~ 2 cm below the liquid to be sucked, and use the suction ear ball to absorb the solution as described above (note that the measuring pipette should not be inserted too deep into the solution, and should be inserted downward while sucking, and always maintain this depth). When the tube head to located about 1 ~ 2 cm above the line, quickly with the right hand index finger plug nozzle (fall at this time if the solution to the tong, should learn from the back), the measuring pipette to suction surface is put forward, and make the contact tube tip filed after a short stay liquid container wall, using filter paper dry the measuring pipette lower adhesion of a small amount of solution. (When moving the measuring pipette, the measuring pipette should be kept vertical, not tilted.)

Regulating liquid level

Take another clean beaker in the left hand and place the tip of the measuring pipette close to the inner wall of the beaker. Keep the beaker tilted so that the measuring pipette is vertical and the scale line and the eye level (the left hand should not touch the measuring pipette). Loosen the index finger slightly (you can turn the measuring pipette slightly), so that the solution in the tube slowly flows out from the lower mouth. When the liquid level reaches the scale line, press the right index finger tightly, pause for a moment, and then press the upper method to put the bottom line of the meniscus of the solution to the tangent with the upper edge of the mark line, and immediately press the tube mouth with the index finger. Place the tip close to the inside of the beaker and move a little toward the beaker to remove any drops from the tip. Carefully move the measuring pipette into the container receiving the solution.

Effluent solution

The pipette upright, receiver tilt, pipe bottom close to receiver walls, open your second finger, the solution along the receiver down walls, tube after the solution flow, keep stay 15 s fluid status, the measuring pipette tip in receiver by point by wall slip a few small distance before and after (or rotate the measuring pipette tip by receiver inside a week), Remove measuring pipette (the small amount of solution remaining on the inner wall of the measuring pipette tip should not be forced out by external force because the volume of the retained solution at the inner wall of the measuring pipette tip has been taken into account when calibrating the measuring pipette. )

Clean the instrument

Clean measuring pipette and place on measuring pipette rack.

3 Matters needing attention

1. Measuring pipette should not be dried in an oven.

2. The glass measuring pipette should not move too hot or too cold a solution.

3. As far as possible, the same pipette measuring should be used in the same experiment.

4. After the measuring pipette is used, it should be immediately rinsed with tap water and distilled water and placed on the measuring pipette rack.

5. Measuring pipette and volumetric flask are often used together, so the relative volume of the two is often calibrated before use.

6. In use, in order to reduce measurement error, each time from the top scale (0 scale) as the starting point, to lower the required volume of the solution, rather than absorb as much volume as needed.

As a  measuring pipette manufacturer & supplier of medical equipment and equipment, Huida can not only provide customers with overall solutions for laboratory equipment, but also provide a full range of high-quality products and related services for laboratory glass wares. Welcome to send an inquiry for more details.