Liquid Handling

PLT unitUse and HandlingTesting with and without tipTo check the overall pipettesystem, the test is conductedwith a mounted, unused tip.When a leak has been identified,the test can be repeatedwithout a tip to determinewhether the leak arises fromthe tip cone/tip couplingregion.Dynamic or static test?The dynamic test can rapidlydetermine whether a defectivepiston (contamination,scratches, etc.) has caused aleak. The pipette button mustbe pushed down numeroustimes during the measurementperiod. The associated pistonmovement allows a defectivepiston to be recognized.In the static test, the pipettebutton is not pressed duringthe test procedure, i.e. thepiston doesn't move. This willonly determine a leak in a generalway, without attributing itto a particular component.Featuresn Limit values for the commerciallyavailable singleandmultichannel pipettesin the volume range 1 µl to10 ml are pre-programmed.n Testing with and withouttipsn Test results in secondsn Patent pendingLiquid HandlingMain MenuA wide variety of submenuscan be selected from themain menu, e.g., pipette type,volume range, self-test, andsettings (language, shut-offtime, pressure units, etc.)Main MenuPipette TypeSelf TestSwitch OFFSettings...Auswahl selectzurück backLimit valuesThe limit values referencedduring testing represent awarning limit, from which significantlylower volume valuescan also be determined gravimetrically.This is one quarterof the volume tolerances,according to ISO 8655-2.The limit value for the leak volumeof a given pipette allowsthe leak rate to be calculated.These calculations, which arebased on over 35 years ofexperience in the developmentand production of pipettes, includethe dead volume and theintake characteristics, amongother things.If the pipette is mechanicallydefect-free, clean, and thetest is carried out properly withthe BRAND PLT unit, then theinstrument is within the ISO8655-2 tolerances.The marks in the verticalprogress bars in the displayrepresent the resident limitvalues for the leak rate Q L .PASSSC – 100 µlQ L: 0.04 hPa * ml/sstartWith the correlation table inthe PLT operating manual,the missing volume can beapproximately determined fromthe leak rate. The level of theprogress bar in the displayindicates whether the pipetteis leak-tight, and whether itlies within the tolerance limitsor leaks.FAILSC – 100 µlQ L: 4.6 hPa * ml/sstartwww.brand.de 107