Metrolab Blog

From calibration curve to photometric method data

  • The chemical reaction for the determination of the substance must be known.
  • The optimal wavelength for the measurement must be known, otherwise a spectrum must be recorded to indicate maximum peak or suitable λ.
  • Setting up a dilution series for e.g. a 10-point calibration: A dilution series in duplicate achieves a higher accuracy.
  • After reaction and reading, the absorbance values are plotted against the concentration values.

Today, photometers offer user-guided functions to set-up user-defined or pre-programmed calibration

  • General settings for cuvette size, measurement range, wavelengths etc.
  • Reading of dilution solutions including calculation of the mean values of duplicates.
  • Alternatively, entering simply the slope factor.
  • Blank values (E0) can be stored.
  • Calibration characteristics are stored with a method (program) identification (number or name)
  • Automatic setting of wavelength and measuring range during method selection via list or Barcode.
  • Switching citations and units
  • Setting for AQA default values for standard solutions and checking intervals

Here you can download the whole article as a PDF: