Distinguishing positional isomers of hexachlorinated biphenyls by ion-molecule reactions in a triple-quadrupole instrument

The ion–molecule reaction between six hexachlorobiphenyl positive molecular ions and ammonia in a triplequadrupole instrument to yield [M + NH3 – HCl]+. ions gives products whose abundances differ by at least an order of magnitude under uniform conditions. This reaction offers a way of distinguishing many isomers by a reaction that is different from the other demonstrated route, the loss of HCl from [M + O – Cl]− ions.