Headspace analysis

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Headspace analysis

  1. 1. AnalySys Sciences 1 Instrumental in your success http://analysciences.com http://analysciences.com
  2. 2. Headspace analysis ©Analysys Sciences
  3. 3. What is headspace? 'Headspace' is the gas space above the sample in a chromatography vial. Volatile sample components diffuse into the gas phase, forming the headspace gas. Headspace analysis is the analysis of the components present in that gas.
  4. 4. Applications Headspace analysis is most suited for very volatile analytes, in solid or liquid samples. Residual solvents in pharmaceuticals Flavors in beverages Fragrances in cosmetics Alcohol in blood / urine
  5. 5. Advantages Minimal sample preparation. In fact, almost no sample preparation. Can be used for difficult sample matrices like blood, powders, pastes, &c. Easy to automate
  6. 6. Headspace vials and septa The right vials and septa must be used. Headpace vials are flat-bottomed or round-bottomed, from 6ml to 20 ml. Septa and crimp caps are used to ensure no leaks.
  7. 7. Partition co-efficient (K value) K value directly affects the efficiency of headspace analysis. Lower the K value, higher the sensitivity of the analysis. K value can be lowered by: increasing sample temperature or by adding inorganic salts to the sample matrix. M sC K C  Cs = concentration of the analyte in the solid phase Cm = concentration in gas phase.
  8. 8. Phase ratio (b value) Lower b value will yield higher response. b value can be lowered by increasing the sample volume. Vs = volume of solid phase Vg = volume of gas phase
  9. 9. Typical headspace analyser Carousel type Automatically analyse upto 10 vials. 50 methods can be stored. Motorised needle for automatic sample injection Needle is automatically cleaned between analyses. Can be connected to any GC instrument.
  10. 10. Headspace: Pharma applications •Determination of residual solvents in pharmaceuticals by USP method 467 •Residual solvents are used or produced in the manufacture of pharmaceuticals. •USP 467 specifies headspace analysis for the estimation of residual solvents.

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