Amethod for quantitative analysis of acetylene in blood and urine samples was investigated. Using cryogenic
gas chromatography–mass spectrometry (GC–MS), acetylene was measured with isobutane as the
internal standard in the headspace method, which revealed a linear response over the entire composite
range with an excellent correlation coefficient, both in blood (R = 0.9968, range = 5.39–43.1g/ml) and
urine (R = 0.9972, range = 2.16–10.8g/ml). The coefficients of variation (CV) for blood ranged from 2.62
to 11.6% for intra-day and 4.55 to 10.4% for inter-day. The CV for urine ranged from 2.38 to 3.10% for
intra-day and 4.83 to 11.0% for inter-day. The recovery rate as an index of accuracy ranged from 83 to
111%. The present method showed good reliability, and is also simple and rapid. In actual samples from
a charred cadaver due to acetylene explosion, the measured concentrations of acetylene by this method
were 21.5g/ml for femoral vein blood, 17.9g/ml for right atrial blood, 25.5g/ml for left atrial blood
and 7.49g/ml for urine. Quantification of acetylene provides important information, because the acetylene
concentration is a vital reaction or sign. For example, when acetylene is filled in a closed space
and then explodes, in antemortem explosion, the blood acetylene concentration of the cadaver might
be significant. On the other hand, in postmortem explosion, acetylene is not detected in blood. Furthermore,
when several victims are involved in one explosion, comparison of the sample concentrations can
also provide useful information to establish the conditions at the accident scene; therefore, the present
method is useful in forensics.