Calibration Curves
December 9, 2022
Dripwater Calibration Curve
Based on the ten-fold dilution and the data found in Tremaine and Froeldich (2013), Owen et al. (2016), and unpublished Banner group data (R. Hatch, P. Carlson, and N. Miller) we created calibration standards to include the full range of concentrations we predicted to be in our dripwater samples. In order to calibrate for analysis, a set of calibration standards are created by serially diluting known concentrations of the analyte elements and bracket expected unknown concentrations. Calibration standards were made gravimetrically using NIST-certified multi- and single-element standards (see dilutions spreadsheet for more details).
The table below details the concentrations of each analyte in all six calibration standards (ranging from a blank to a high-concentration standard). The range observed in the measured unknowns has been bracketed in bold. The median estimated unknown concentration is filled dark green. The rho value (in red) describes the linearity of the calibration curve.
Table 3: Calibration standard concentrations for each analyte (ppm)
Plate Calcite Calibration Curve
We decided to use ratio mode on scraped calcite to reduce analysis time and increase precision since we were able to assign a known concentration of calcium based on stoichiometry. To achieve this, all trace element analytes were included in the calibration standards. Based on the ten-thousand-fold dilution and the data found in Tremaine and Froelich (2013), we created calibration standards to include the full range of TE/Ca ratios we predicted to be in our plate calcite solutions. The table below details the TE/Ca ratio of each analyte in all six calibration standards (ranging from a blank to a high-concentration standard). The range observed in the measured unknowns has been bracketed in bold. The median measured unknown ratio is filled dark green. The rho value (in red) describes the linearity of the calibration curve.
Table 3: Calibration standard TE/Ca ratios for each analyte (ppt/ppm)