Sulphonamide injections

Cure system species, accelerators and their reaction products This class of additive can present problems as they are often thermally labile, reactive and, in some cases, have a degree of ionic character (e.g. zinc dithiocarbamate salts). In these cases LC-MS is a more appropriate technique than GC-MS. It is also easier to use LC-MS with a number of the approved food simulants as they can be injected directly into the instrument, being compatible with the mobile phase. In some cases the reaction products (e.g. aniline from diphenyl guanidine, and benzothiazole from thiazole and sulphonamide accelerators) are stable and so GC and GC-MS can be used. Peroxides are popular curatives for food use rubbers and the stable, breakdown products of these can be easily detected by GC-MS. 

Sulphonamides in pharmaceutical preparations and urine were determined indirectly using flame AAS by continuous precipitation with copper or silver, as proposed by Montero et al.[22]. The copper method exhibited a better selectivity, and only this was used for determinations in urine. The precipitate, formed by injecting one of the cations into a carrier containing the sample, was collected on an on-line filter, and the peak absorbance of the residual metal in the stream passing through the filter was measured. The decrease in peak height compared to a blank was then related to the sulphonamide... 

Moniero et al.[24] developed an indirect AAS method for the determination of local anaesthetics (lidocaine. tetracaine and procaine hydrochlorides) in pharmaceutical preparations using FI on-line precipitation-dissolution. A cobalt solution is injected into a carrier stream containing the sample, and the precipitate formed is retained on an online stainless steel filter. The determinations were made by measuring the residual cobalt concentration in a similar way as for the indirect determination of sulphonamides (cf. Sec. 9.4.2). A sampling frequency of 100 h was achieved with a precision of 0.6% r.s.d.. 

Reactive in solution Permanganate Tetrahydropalmatine (tablets) reserpine (Ph) rescinnamine (Ph) yohimbine (Ph) medazepam (Ph) cefadroxil monohydrate (Ph and BF) salicylamide (Ph and urine) perphenazine (synthetic formulations) dipyridamole (tablets and injections) etilefrine hydrochloride (Ph and BF) isoxsuprine hydrochloride (Ph and BF) prenalterol hydrochloride (Ph and BF) amidopyrine (Ph) pipemidic acid (Ph) ethamsylate (Ph) folic acid (Ph) sulphonamides (Ph) chloramphenicol (Ph)... 

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