Toxicological screen on gastric aspirates: the Singapore experience.

In the early eighties, in response to increasing self-poisoning incidents by pharmaceuticals in Singapore, a comprehensive wide-sweep screen for these drugs in clinical gastric aspirates was devised and implemented by us. The toxicological screen which involved quadruplicate extractions, two in acidic conditions and the other two in alkaline conditions, required the following analyses to be carried out: UV on the acidic fraction, TLC on the basic fraction and mega-bore capillary GC/NPD (nitrogen phosphorus detector) on the combined fraction. The combined fraction if necessary was subjected to GC/MS analysis. Our screen satisfied the need to confirm the analytical outcome of one method by another. Combining the acidic and basic fractions for a single GC analysis saves on instrument time and manpower. All coma and emergency cases were required to undergo GC/MS analysis to prove the identity of toxic agents beyond reasonable doubt. Quality control procedures were instituted at key steps to ensure quality of analytical outcome.