# The Correction of the Pipette

1. After using the pipette for a period of time, check if correction is needed to ensure accurate range. Generally, it is routinely inspected for 3-6 months, and it is carried out at around 20-25 degrees. The specific operations are as follows:
1) Pipette the distilled water 3 times and discard it, then use a pipette to draw 1000 ul and 100 ul of 3 distilled water or deionized water 10 times each time, and weigh the actual weight after each weighing (on the most accurate balance). The average value of 10 times is recorded as m1. (How many volumes to choose depends on the maximum range of the pipette and 10% of the maximum range (eg 200ul and 20ul for two guns)
2) Check the thermometer value, find the density value of distilled water at this room temperature, and calculate the standard weight m2 of 1000 ul and 100 ul distilled water.
3) Calculate the accuracy A, the formula = (m1-m2) / m2 * 100, if it is within the allowable error range, no correction is needed, if it is exceeded, the correction is selected.

2. Correction
Method: According to the comparison result of the first step, if the actual weight is greater than the standard weight (m1>m2), indicating that the liquid volume removed by the pipetting gun is larger than the actual volume, the volume of the pipette should be reduced, and the actual weight is approached the standard weight. Use a tool to adjust the nut counterclockwise. The opposite is reversed. This is repeated until the standard weight is adjusted.