Using 4-channel pipette is much easier for sample loading onto agarose gel than with 8- or 12-channels, because pipette tips are frequently set unevenly. In such a case it is difficult to apply samples into all the wells at a time. It is much easier to adjust direction of tips by fingers for 4-channel pipette than for 8-channel. The 4-channel pipette is also easier to use with gels of various sizes and number of wells. It may take more time than 8- or 12-channel pipette but is much quicker than single pipette.

Gels with 25-26 lanes fit well with 4-channel pipette. One or two more lanes are necessary for molecular weight marker along with samples (4 x 6 + 1 = 25). If you were trying to use gels with 17-18 lanes, too many (six) gels are necessary for 96-well PCR products. On the other hand, it is a little more difficult to handle a larger gel with 33-34 or more wells. Anyway 4n+1 or 2 lanes are necessary for 4-channel pipette. An electrophoresis apparatus with 32-lane comb which fits 8-channel pipette, says the supplier, is commercially available, but I wonder if they imagined the real lab systems. Where can we apply molecular weight marker?

Commercially available 4-channel pipette.

Several multi-channel pipettes are available from suppliers. Most of them are of 8- or 12-channels. I know only one 4-channel pipette available at present from the BIOHIT (Finland). It seems a rare item, and I hope the supply would not be expired.

Electrophoresis apparatus with four or six-staged 26-lane combs.

Electrophoresis apparatuses with 26-lane comb are available from the Advance (Japan) and Cosmo Bio (Japan). Spacing of the comb fits multi-channel pipettes (alternative wells). Their gel trays have several sets of guide groove for combs. This allows a four-staged electrophoresis of 96 samples at a time (fit with 96-well PCR products) or at most a six-staged run of 144 samples (Cosmo Bio only). Their medium sized gels allow easy handling and save lab space.

Mupid-EX electrophoresis apparatus.

iMyRun electrophoresis apparatus.

A tapered 26-lane comb of Mupid-EX makes wells with bigger mouth so that it is easier to apply samples with multi-channel pipette. Narrower gel margin of iMyRun ensures longer effective gel length.

A big demerit of both is that their electrophoresis chambers cannot be ice-chilled like the old type Mupid as shown below.

The old type Mupid has a power plug higher than the gel tray bottom so that it can be chilled by ice (yellow arrows).

It is, however impossible to put ice around Mupid-EX. It is also difficult to put ice around iMyRun chamber higher than the bottom of the gel tray, because the power plug is a little lower than the bottom (orange arrow).