Home Forums Iolite User Forum using multiple calibration standards

This topic contains 5 replies, has 4 voices, and was last updated by  Dr Tephy Marillo-Sialer 1 year, 8 months ago.

  • Creator
    Topic
  • #7821

    Robert Thompson
    Participant

    Is it possible in Iolite to make use of more than one calibration standard in a laser ablation sequence? The drop down menus only permit me to select one standard when I use trace elements IS DRS – I would like to try using more than one if possible.

Viewing 5 replies - 1 through 5 (of 5 total)
  • Author
    Replies
  • #7825

    Hi Robert,

    Unfortunately, no. A multi-point calibration is actually quite complex when you’re looking at time resolved data.

    #8283

    Benjamin Parks
    Participant

    Hi all,

    I have Igor Pro v6.37 and iolite on trial on a Windows PC. For processing the data of laser ablation spot analyses, I understand that you can identify multiple reference standards under the “reference materials” tab. At the point where you “crunch data” on the DRS tab, must a user only choose one reference material (e.g., BIR-1G vs. NIST-612) to be used in crunching the data?

    For instance, what if you did the same thing as in the demo from the user manual section 4.4.1 (analyzed NIST-612, BCR2G, BHVO 2G and BIR 1G). And in addition to analyzing all of these standards let’s say you also had unknown sample analyses interspersed in the raw data set and wanted to use all of the reference standards to crunch the data in a DRS. However it seems as if, even when using the Trace_Elements_IS DRS, you must select only one of the reference standards as the one to be used to crunch data (in the demo, they use NIST-612). But what if you want to use more than one? Can Iolite produce a callibration curve of the measured vs. preferred concentrations of multiple reference standards?

    Thanks,
    Ben Parks

    #8303

    Hi Ben,

    iolite uses a single well-characterised reference material to calibrate LAICPMS measurements and provides the option to easily switch between measured reference materials to verify this calibration.

    #9732

    Jared Wesley Singer
    Participant

    Hi,

    Multi-point calibration is a staple of analytical controls, and it is especially appropriate [if not imperative?] to implement multi-point calibration for laser ablation in Iolite. Manually generating multi-point curves for many channels becomes a impossibly tedious exercise of data entry and spreadsheet manipulation. [This is the world’s smallest violin…]

    It is not strictly necessary to generate multi-standard calibrations in time-resolved mode. For example, a single well-characterized reference material can still serve as Primary standard in the usual time resolved way. Meanwhile other standards present in the run could be integrated and processed like Output_1. In a final calibration loop the secondary standards could be regressed as “X_ppm” vs. “ACCEPTED-VALUE” and generate new “X_ppm_CORRECTED” output channels using a calibration curve for each channel. The user could inspect the curves in the X-Y plot area.

    Even easier to implement, Iolite might just include an optional data table output of “ACCEPTED VALUES”. Any standard analysis in the run, whether primary or secondary, could have “X_ppm” and “ACCEPTED-VALUE” adjacent in the Data Table export. This option at least eliminates the data entry part, and the data table export is ready to plot multi-standard curves in spreadsheet form.

    To Tephy’s point about the complexity, I have seen the slope of multi-standard curves shift from one sample exchange to the next (perhaps a cell design issue) and slopes depending on matrix composition–no doubt this could be next-level implementation. Do any able programmers know how to implement this?

    Much obliged for your efforts,

    Jared

    #9758

    Thanks for the feedback!

    We are already assessing different approaches and hope to find a robust way to tackle this topic.
    In the meantime I will add your suggestions to the list of developments, we might be able to incorporate them (or something along those lines) a bit sooner.

Viewing 5 replies - 1 through 5 (of 5 total)

You must be logged in to reply to this topic.