Here a single aspiration step is performed, followed by priming dispenses, then incremental dispenses into dry plates as follows:
Data Acquisition and Processing
Absorbance data is acquired on a Wallac Victor2 reader using the same read protocol as for the calibration plate. The raw results are exported to ExcelTM and %CV is calculated. The volume dispensed is calculated by comparison of signal to a manually prepared calibration standard.
Testing has been done for three and five incremental plates using the method described above. For each run, the volume dispensed and %CV for each plate is calculated and summarized (Table 1). The results for the two runs are represented graphically (Figure 3).
In this preliminary work we have found that the Sciclone ALH equipped with a Low Volume Head is capable of delivering 0.5μL of liquid into dry microplates with a precision of less than 6%CV. This is performed with no direct contact between the cannulas and the plate. In the above results, a "first plate" effect is observed, in which the first plate in a series has a higher volume. We believe this is due to residual tartrazine solution of the external surfaces of the cannulas that is removed as the first plate is dispensed.
Initial dry plate work was carried out using a 384 Cannula Array. The benefits of this array are that it can access both deep well plates and standard microplates. However, the larger cannulas do not permit formation of well formed droplets. Without such droplets, physical cont