Liquid Chromatography Tandem Mass Spectrometry

Separation of structurally similar compounds based on subtle differences in chemical properties.

  • HPLC columns separate target substances based on subtle differences in chemical properties
  • Each substance travels through the column at a reproducible rate allowing a unique retention time to be established
  • In order for a substance to be confirmed to be present, it's retention time must match with the established value
  • The InSource Diagnostics laboratory has carefully validated each of our testing methods to ensure that all structurally similar compounds have unique retention times

A unique chemical fingerprint is established for each target substance based on the chemical structure.

  • Molecules are ionized using heat and high voltage energy
  • The Q1 zone of the mass spectrometer filters the ionized targe substance based on their mass to charge ratio (m/z)
  • The Q2 zone then fragments the ionized substance further by bombarding it with high energy gas
  • The molecules break apart in a reproducible fashion into new fragments with a unique mass (product ions)
  • The Q3 zone of the mass spectrometer then isolates the appropriate productions
  • Based on the ratio of the ions isolated in the Q1 and Q3 zones, the identity of a target substance can be determined


The exact concentration of the drug is determined.

  • The amount of ions produced by a target substance is related to it's concentration
  • A calibration curve is generated that describes the signal response for a known concentration of the targeted substance
  • By comparing the signal response of the substance in a patient sample to the calibration curve, a concentration of the substance can be determined

Changing the World. One Test at a Time.

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