0 Replies Latest reply on Mar 14, 2019 12:35 PM by agricult

    ICP-OES 5100 Method Development Tools & Advice

    agricult

      Hi,

       

      I was hoping to get some advice on how to apply some of the 5100 VDV OES features to assist in my method development work, i.e. Intelliquant, Trend analysis, Confirmatory wavelengths. I think I've already a fair idea of how to apply these tools but it would be great to receive some feedback to ensure I'm on the right track.

       

      Trend Analysis:

      This feature located on the analysis tab provides trend information on the Argon Intensity and Nebuliser back pressure during a full quantitative analysis. I would think the feature would be useful as follows:

      1. Identifying a suitable sample dilution factor. For example, if using a dilute & shoot method to analyse Serum samples, the Nebuliser pressure monitor may show that higher argon pressure is needed to push through samples diluted 1:20 compared with samples diluted 1:50 and 1:100. An increasing neb. pressure could predict a possible blockage from low dilution samples since they haven't been digested. Would this be a correct application?If so, what is a desirable nebuliser pressure to maintain?

      2. Using the Argon Intensity monitor again to determine 1) suitable sample dilution, i.e. a high matrix sample at a 1:20 dilution may cause greater plasma cooling effect than samples diluted 1:50 and 1:100 and therefore lowering the energy required to excite the analyte electrons, possibly giving falsely low results. 2) atypical samples which have a different matrix composition than typical samples causing a large fluctuation in the argon intensity.  Would this be a correct application? If so, how large of an intensity fluctuation would be considered significant?

       

      Confirmatory Wavelengths:

      When using 2 wavelengths for various elements - primary and confirmatory, how big of a difference in concentration values between them would be significant or indicative of an interference? For example, primary reads 1.00 ppm and confirmatory reads 0.98 or 102 ppm, I assume this is just acceptable variation but a primary reading of 1.00 ppm and a confirmatory reading of 0.45 ppm or 2 ppm, would indicate some interference even if its not visible on the spectral view? Would this be a correct interruption?

       

      Calibration Curve Linearity Challenge:

      To test if the calibration curve range chosen for your standards is linear, is it acceptable to challenge the curve by running the same standards against the curve as 'samples' in a randomized order. If you are getting back close to the known concentration then its a sign that the curve range is linear? Apart from a r2 value of close to 1.0.

      I presume using single element standards is more appropriate than a multi-element to rule out interference but when you move on to using a multi-element standard what tests could you try to check if the linearity hasn't been impacted by the multi-elements? Possibly running the multi-element standards as randomized samples maybe . . . .

       

      I appreciate the feedback