Bio-Rad S3™ Cell Sorter - Manual (Page 49)

Instruction Manual | 39
4.4 Quality Control
Fig. 39. QC histograms displayed in the workspace.
4.4.3 Alignment
During the alignment phase, automated micro-motors sweep the fluidic stream through the
laser beams to find the point of optimal illumination. This automated process requires the
stream and laser(s) to be running. After alignment, the CVs and voltages are compared to the
QC criteria. During the QC procedure, a calibration protocol will open and run automatically.
Upon completion, the data are saved as an FCS file. This file may be opened and viewed by
opening the daily QC report, selecting the desired date and time, and clicking the open FCS file
button at the bottom of the report.
4.4.4 Drop Delay Determination
After the droplet and side stream formations have been optimized and the system is optically
aligned, drop delay will be determined using ProDrop
™ technology and set using the same
ProLine Calibration Beads used for the alignment.
ProDrop technology accurately calculates the drop delay on the S3 and S3e Systems by
analyzing the waste stream while running calibration particles. Events are detected normally at the
nozzle and then again in the waste stream below. The drop delay setting is adjusted automatically
through a set range, first coarsely then finely, while sorting is enabled. The correct drop delay
value is determined when the calibration particles are deflected from the center stream and
therefore no longer present in the waste stream. This technology allows accurate measurement
of the drop delay value without requiring the user to count beads under a microscope.
While the ProDrop technology is running, the Drop Delay Alignment Status window will open.
The yellow line indicates the best drop delay during the process and this value will be set as
the drop delay once completed. The green points, light green for coarse adjustments and dark
green for fine adjustments, indicate the number of beads detected in the waste stream. After
completion, three buttons will appear in the lower right corner. These buttons, from left to right,
recalculate drop delay, run a verify drop delay test, or confirm and close the window (Figure 40).