although the prior formation of an unstable intermediate is not excluded. 4. The poor conversion ofesters ofD-galacturonic acid into compounds ofL-galactonic acid appears to be due mainly to the reversible inhibition of the enzyme during the course of the reaction, and to a lesser extent to the instability of the galactonic acid derivative formed. The substance responsible for the inhibition of...

A simple, highly sensitive chemiluminescent method using flow injection is described for the determination of three substituted benzamides, namely: sulpiride, sultopride and tiapride. The method is based on the sensitizing effect of these drugs on the chemiluminometric oxidation of sulphite by cerium(IV). The different experimental parameters affecting the chemiluminescence intensity were caref...

Sampling of monoterpenes from air on the Tenax porous polymer may introduce analytical errors owing to oxidation and acid rearrangements on the adsorbent. Particularly terpenes which react rapidly with ozone, e.g. myrcene and limonene, are partially lost when sampling air with high photooxidant levels. On acidified adsorption cartridges, a-pinene and ~-pinene may be converted to camphene, limon...