Pipette transfer

Pipettes are of two kinds (i) those which have one mark and deliver a small, constant volume of liquid under certain specified conditions (transfer pipettes) ... 

Automatic pipettes. The Dafert pipette (Fig. 3.2) is an automatic version of a transfer pipette. One side of the two-way tap is connected to a reservoir containing the solution to be dispensed. When the tap is in the appropriate position, solution fills the pipette completely, excess solution draining away... 

Transfer Pipettes They have only one specific mark engraved on them and are specifically employed to deliver (or transfer) a definite volume of liquid under certain specified conditions, and... 

The British Standards Institution (BSI) has laid down the permitted tolerances and delivery times for commonly used bulb transfer pipettes as shown in Table 2.5. 

The USP specifies the following tolerances accepted by the National Bureau of Standards for transfer pipettes ... 

The salient features of single-graduation mark transfer pipettes are ... 

Use of the Transfer Pipette The following steps mentioned sequentially must be followed while making use of a transfer pipette ... 

Presently, many analysts make use of pipette filler for sucking in and draining out of liquids from the transfer pipettes for obvious reasons. 

Automatic Pipettes (Transfer Pipettes) Automatic pipettes are always preferred to ordinary transfer pipettes because of their ability to handle corrosive and toxic liquids in routine analytical laboratories, e.g., determination of Iodine Value in edible oils by iodine-monochloride (IC1) solution. 

O O A student uses a transfer pipette to put 25.00 mL of 0.100 mol/L acetic acid into an Erlenmeyer flask. Then the student adds sodium hydroxide from a burette to the flask, and records the following readings of volume and pH. 

Holmes, F. E. Transfer Pipette for Solvent Extraction. Chemist-Analyst S3, 20 (1964). 

Nondrug-related impurities can be extracted from various components employed in the sample preparation of a low-dose drug product. Classic sources of this type of contamination are glassware,20 filters, centrifugation tubes, HPLC vials and caps and transfer pipettes.20 Chemicals from the pH electrode can also be extracted into the sample diluent while adjusting the pH of the solution. In addition, impurities in reagents used in sample preparation1 can pose issues. 

Step 3. Place a 50-mL beaker under the column to collect the eluent fractions. Add the uranium sample in 3 M HC1 from Step 1 to the top of the column with a transfer pipette. Open the stopcock to let the solution flow at a rate of about 1 mL/minute. Record the time of uranium separation. Rinse the beaker that contained the uranium sample twice with 5 mL of 3 M HC1 and pour it through the column. Pass an additional 10 mL of 3 M HC1 through the column. Then wash the column with 4 mL of concentrated HC1. Close the stopcock when the liquid just covers the resin. 

Step 15. Transfer the sample with a borosilicate glass Pasteur pipette or plastic transfer pipette to a prepared electroplating cell. See diagram (Fig. 15.3) of electroplating cell and cell preparation procedure given below of electroplating planchet and cell. 

Step 24. Remove the electrode from the cell and turn off the power. Promptly use transfer pipette to discard the solution. Rinse the disk in the cell with 1% solution of ammonium nitrate in 1 99 ammonium hydroxide from a squirt bottle. Discard rinse. 

The 5 mL tube is placed in a magnetic field (DYNAL MDC 1) for 2 min, the supernatant is gently removed with a 1 mL disposable polypropylene transfer pipette. Resuspend the beads in 2 mL HBSS/1% BSA and place the tube in the magnetic field again for 2 min. Collect the supernatant, combine the 2 supernatants and centrifuge at 300,g for 10 min. Resuspend the cells in the desired volume of HACM. 

A transfer pipette (bottom) measures a fixed volume of liquid, such as 10.00 mL, 25.00 mL, or 50.0 mL A burette (top) measures a variable volume of liquid. 

Two 1-mL transfer pipettes, used to dispense the standard amounts of sucrose and enzyme solution... 

One 2-mL transfer pipette, nsed exclusively for dispensing the dinitrosalicylate reagent... 

One 5-mL transfer pipette, nsed exclnsively for dispensing the NaOH solntion required in parts F and H of the experiment... 

Two 1-mL transfer pipettes one 2-mL transfer pipette one 5-mL transfer pipette one 1-mL graduated pipette two 2-mL graduated pipettes one 25-mL graduated cylinder or pipette pipetting bulb glass-stoppered flask volumetric flasks, beakers, test tubes. 

Typical volumetric glassware (a) volumetric flask, (h) transfer pipette, (c) measuring pipette,... 

Measuring pipettes are essentially small burettes without stopcocks. As with burettes, the need for adequate drainage time cannot be ignored. Because of the double reading involved in the use of measuring pipettes and the additional manipulation required, they are neither as precise nor as accurate as transfer pipettes, but they are quite satisfactory for semiquantitative operations. 

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