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Micro-bomb Calorimetry

by Jim Karagatzides, Harvard Forest

CalibrationSet-upList of MaterialsLoggerNet Instructions and Datalogger files


The micro-bomb calorimetric method described herein was provided by KL Griffin. In this setup, a[Figure 1. Micro-bomb calorimeter (with electrodes from ignition unit) fitted to a stainless steel cross. Thermocouple inserted into top portion, connected to a datalogger. Quick-connect (right-side) for oxygen supply.] thermocouple is inserted directly into the bomb chamber and a datalogger used for rapid (<5 seconds) measurement of heat of combustion (maximum temperature; Figure 1). As with othe
r bomb calorimeters, the instrument is calibrated against a standard of known calorific content (e.g., benzoic acid). Most analysts run each sample in duplicate and undertake a triplicate analysis if the difference exceeds 2%.

Click here for an exploded view. 

Useful Tips

  • Clean parts with ethanol being careful of leaving behind fibers if you use any cotton swabs.
  • Store wire in ethanol and cut wire pieces in advance.
  • Check the system for leaks after putting the bomb together with soapy water (or Snoop); the best approach at first may be to immerse the whole unit in water.
  • Use gloves and do not touch anything with your fingers as oils on your hands will contaminate the sample.
  • A Sonicare cleaning system (usually used for jewelry) may remove built up ash.
  • Additional standard reference material for calibration is available (NIST 203_1.pdf)