CSols AutoDil Software – Frequently Asked Questions
General
- What is the CSols AutoDil software?
AutoDil is a software application (app) which is part of the Teledyne CETAC Technologies High Performance Liquid Dilution (HPLD) system. The HPLD system comprises the ASX-560 Autosampler and SDX Dilutor and is designed to work with all ICP and ICP-MS instruments from different vendors.
- What does the CSols AutoDil software do as part of the HPLD system?
AutoDil monitors analysis of all the samples in a batch analysis run. When the run is completed it will automatically undertake the following actions:
i) Decide if any of the instrument concentration results for the analytes measured are above the upper detection limit (upper range) of the instrument.
ii) Calculate a suitable dilution factor for each sample
iii) Start a new repeat instrument run, instructing the HPLD system to dilute and re-analyse only those samples that have results that are above the detection limit.
- What components of the ASX-560 Autosampler and SDX Dilutor are available for control by AutoDil
AutoDil can control the following:
- Autosampler
– Arm (all sample positions and the probe rinse station)
– Peristaltic pump (for rinse station) - Dilutor
– Syringe (to draw up sample from tubes)
– Syringe (to dispense sample and diluent into vortex mixer)
– Multiport valve (switching during different syringe movement)
– Peristaltic pump (Rinsing vortex mixer) - Vortex mixer
– Speed and duration of mixing
What is the sequence used by AutoDil to carry out the dilution process?
The following steps are used:
i) Move sample probe to those samples requiring dilution
ii) Draw up a calculated target amount of sample to perform the required dilution (N.B. The working vortex volume is 9 ml)
iii) Move sample probe to the probe wash station and rinse probe
iv) Move sample probe to the vortex mixer
v) Dispense sample into vortex mixer
vi) Dispense diluent into vortex mixer
vii) Start vortex mixer
viii) Lower sample probe into vortex mixer
ix) Aspirate sample into Instrument
x) Raise probe, move to wash station & rinse
xi) Rinse vortex mixer
Repeat for next sample requiring dilution
- How different will operation of the HPLD system and AutoDil be compared to my current workflow?
Working with AutoDil will be very similar to your current operation. Samples would be prepared and loaded into the autosampler in the normal way. Method and sample information would then be entered into the instrument software run queue also as normal. Then AutoDil would be activated before the run is started.
AutoDil will monitor the run in background and if any of the sample results are over range at the end of the run it will automatically perform all of the required dilutions without any further user intervention. AutoDil will then collate all the results together (diluted and non diluted) at the end of run for you to review and report.
Consequently there is no need to find and take out over range samples from the autosampler and manually dilute them before then re-running them, saving considerable time and effort
Dilution
- How does AutoDil know if it should dilute a sample?
AutoDil will trigger dilution of a sample if any of the calculated concentration results, for any of the analytes, are greater than the upper detection limit (over range) for that analyte.
- How does AutoDil know what the upper detection limit is?
The upper ranges are either loaded electronically from the instrument methods by Autodil or are entered manually into the Autodil method.
- How does AutoDil decide what dilution factor to apply?
For each analyte specified in the method, AutoDil will check the user configured dilution rules. Either the dilution factor will be calculated dynamically based on the concentration result, or one or more of a list of predetermined fixed values will be used.
- How is the dynamic dilution factor calculated?
As the quality of analysis is reduced as higher dilutions are performed, Autodil’s strategy is to calculate a dilution factor that is:
- Sufficient enough so that the diluted result is below the upper detection limit.
- Compensates for non linearity of the calibration curve at high concentrations by using a Linear factor.
- Rounded up to a set of preset integer values to ensure simplicity and accuracy of dispensing the diluent.
The calculation used is as follows:
Dilution Factor = Result / (Upper Detection Limit * Linear Factor)
e.g. If sample analyte has an upper range of 300 concentration units, a linear factor of 0.8 and a reported concentration of 400. The Dilution Factor = 400/(300 * 0.8) = 1.67. This would be rounded up to 2.
- What happens if AutoDil decides that more than one dilution factor for the same sample are required and they are different (i.e. Analyte A needs 5x dilution, Analyte B 10x dilution)?
Two separate dilutions are performed on the same sample. As explained before the strategy is to always obtain the best results. i.e. a 10x dilution for Analyte A will result in a poorer quality result than a 5x dilution provided that it is not over range.
If the AutoDil method requires more than one fixed dilution then these are always scheduled into the same ‘repeat’ run.
- How many dilutions per sample will AutoDil schedule?
There potentially can be a dilution for every analyte per sample. However using the dynamic calculation described provided the diluter can both aliquot and dispense the sample and diluent and sufficient diluent exists, then a single dilution will be able to determine the result. As the fixed dilution method uses preset settings the amount of dilutions required will be more difficult to determine but will be higher.
- Once the dilution factor is calculate how does AutoDil work out what volume of each sample to take for the dilution?
As the working volume for mixing is 9ml, the amount of sample is calculated by dividing the working volume by the dilution factor.
- What is the maximum dilution factor that the system can schedule?
The dilution system can reliably draw 45 µl (0.045 ml) of sample from a sample tube. With a working volume of 9 ml in the vortex mixer this allows a dilution of 200 times (9 / 0.045). Further serial dilution with a single SDX dilutor could repeat this process for a 40,000 times dilution (200 * 200). Although this is not currently supported by AutoDil.
- What happens with very high concentrated samples?
Where a sample is being processed using the dynamic dilution method, if an analyte concentration remains above the detection limit after the largest dilution has been used, then AutoDil will not schedule further dilutions and will report these results as ‘>Upper Detection limit’.
- Read delays and wash times for dilutions will be longer than normal samples due to mixing process and additional rinsing. How does AutoDil compensate?
AutoDil updates the read delay and wash time for the diluted samples by amending these settings in a new instrument run file. N.B. This is automatically given a unique name to avoid overwriting the original instrument run.
Result handling
- Once the runs are completed how do I work out which results to use?
Of course once all the dilutions are completed there may be multiple results per analyte per sample. As AutoDil has kept a record of all the samples, their dilutions and results, it is able to consolidate the data and report only these results that can be used. i.e. within the analyte detection limit range.
- I use sample weights to calculate final concentrations. How will AutoDil handle dilutions if these are required?
Sample weights can be introduced in the normal way to the instrument sample queue file and used by the instrument method to report a final concentration. AutoDil’s decision to dilute is driven only by the amount of analytes in the sample tube and uses the correct measured instrument parameter to calculate this independently so that results can be reported in the required way.
- How can I get the results to my LIMS system?
AutoDil will allow you to export the consolidated results to a text file so that this can be transferred to your LIMS systems. AutoDil can also be used with the CSols Links for LIMS interfacing application to directly transfer the result data.
Instruments & Software
- What instruments does the HPLD and AutoDil support?
It is planned to support all ICP and ICP-MS instruments models from all vendors. Delivery of different versions will be staggered once full testing has been completed. Please speak to a Teledyne CETAC representative to get an update on the release of different versions.
- Will AutoDil run on a Windows XP based Workstation?
Yes, AutoDil will run on Windows XP.
Benefits
- How much time am I likely to save using Autodil?
There are substantial savings from using AutoDil. These can be divided into productivity savings from better use of the instrument and those from less analyst time per run.
Instrument productivity
Laboratories often perform smaller runs during day shifts, preparing and scheduling larger runs overnight when the laboratory is not manned. So that when samples are over range they will still need analysing in the morning. As AutoDil automatically runs the over range samples when unattended so that:
- The instrument is ready first thing in the morning for further analysis. This saves the instrument dead time while manual dilutions are carried out and means urgent samples can be scheduled immediately in the morning.
- Results from the overnight run can be released immediately in the morning. This will considerably reduce turnaround times (TAT).
Analyst time
AutoDil replaces the following manual steps
i) Review the sample results from the original run to find the over range samples and calculation of dilution factors
ii) Re-Preparation of the over range samples by removing the sample tubes and preparing the dilutions
iii) Replacing the newly prepared samples in a new autosampler tray or back in the original autosampler positions
iv) Resetting the sample queue or creating a new queue using the original sample details
Depending upon the sample types analysed and industry this may take several hours per instrument run. The analyst time saved by using AutoDil can therefore be diverted into more analysis, increasing productivity and decreasing TAT.
Case studies showing examples of productivity gains will be made available in due course.
Further logic
- I always analyse samples in duplicate and want to be able to schedule the HPLD system to repeat the sample analysis by performing a third replicate if there is a >10% difference between the initial duplicate result values?
This is not currently possible using AutoDil but we are planning to introduce new logic functions to AutoDil to allow this to take place and so save value time and resources.
- Can I flag unusually high sample concentrations with AutoDil?
This is not currently possible with AutoDil, but the CSols Links for LIMS software can be used to flag results that are not over range but are above a certain threshold.
- Can I get AutoDil to automatically repeat samples with unusually high sample concentrations?
This is not currently possible using AutoDil but we are planning to introduce new logic functions to AutoDil to allow this to take place and so save value time and resources.
- Can I automatically repeat my AQC samples?
This is not currently possible using AutoDil but we are planning to introduce new logic functions to AutoDil to allow this to take place and so save value time and resources.
- Can I stop the instrument run if my AQC’s are outside the action limits (>+ or – 3SD)?
This is a much more complex requirement as it requires access to AQC limit values. However while this is not possible at present we are planning to introduce new logic functions to AutoDil to provide this