An examination of the emission spectra produced in a novel multiple-flame photometric detector (mFPD) was performed and directly compared to spectra obtained from a conventional single-flame FPD mode. Through monitoring a broad spectral range from 250 to 850 nm, it was found that the mFPD produces sulfur emission predominantly as S 2 *, but HSO* can also be isolated in the red spectral region. Further, phosphorus emission in the mFPD was found to stem from HPO*, while carbon emission was attributed to CH* and C 2 *. Finally, background emission in the mFPD was determined to be from OH*. Qualitatively, these finding agree very well with the species found in a conventional single-flame FPD. However, quantitatively, the mFPD spectra consistently produced analyte emission bands that were relatively more intense, by as much as a factor of 3. In contrast with this, hydrocarbon spectra in the mFPD yielded significantly reduced relative intensities, owing to decreased C 2 * emission. As well, aromatic and aliphatic hydrocarbons produced much more similar distributions of CH* and C 2 * emission in the mFPD than in the conventional single-flame FPD mode. The results indicate that a relative reduction of C 2 radical and an increase of oxidized carbon in the analytical flame of the mFPD could play a central role in the observed quenching-resistant behavior of this detector.Résumé : Les spectres d'émission produits à l'aide d'un nouveau détecteur photométrique à flammes multiples (« multiple flame photometric detector » ou mFPD) ont été examinés et directement comparés à ceux obtenus à partir d'un détecteur photomé-trique à flamme unique conventionnel (FPD). En étudiant une large bande spectrale comprise entre 250 et 850 nm, il a été constaté que la mFPD produisait une émission de soufre principalement sous forme de S 2 *, mais HSO* peut également être isolé dans la partie rouge du spectre. En outre, il a été découvert que l'émission de phosphore dans le mFPD provenait de HPO*, alors que l'émission de carbone était associée à CH* et C 2 *. Enfin, il a été établi que l'émission de fond produite dans le mFPD provenait d'OH*. D'un point de vue qualitatif, ces résultats concordent très bien avec les espèces trouvées par FPD. Cependant, sur le plan quantitatif, les spectres obtenus à l'aide du mFPD ont systématiquement produit des bandes d'émission d'analyte relativement plus intenses selon un facteur aussi grand que trois. Par opposition, les spectres d'hydrocarbure obtenus avec le mFPD ont présenté des intensités relatives très basses, en raison de l'émission réduite de C 2 *. Par ailleurs, les hydrocarbures aromatiques et aliphatiques ont produit des répartitions d'émissions de CH* et C 2 * beaucoup plus semblables dans le cas du mFPD que dans celui de la FPD. Les résultats montrent qu'une diminution relative du radical C 2 et une augmentation du carbone oxydé dans la flamme analytique du mFPD pouvaient jouer un rôle central la résistance de ce détecteur à la désactivation. [Traduit par la Rédaction]

The properties of subcritical water extraction (SWE) in the sample preparation of pharmaceutical tablets were investigated. Tablets comprised of microcrystalline cellulose excipients broke apart up to 80 times faster in subcritical water than they did in room temperature water, while those containing starch readily broke apart in either. Tablets containing starch were also observed to gelatinize or “paste” over several SWE conditions, impeding subsequent filtration and analysis. This effect was avoidable, however, since it was demonstrated to disappear with increases in extraction time and temperature or decreases in sample size. Using SWE, two common over-the-counter pharmaceuticals were extracted under optimized conditions from tablets comprised of either microcrystalline cellulose or starch excipients. Analyte recoveries of 95% or more were obtained at 150 °C for vitamin C (ascorbic acid) tablets in as little as 8 min for the extraction of a whole intact tablet, 6 min for two half tablets, and 5 min for a ground tablet. By comparison, this occurred at 250 °C in just 2 min for an intact slice of an acetaminophen tablet. Reproducibility was generally quite good with these trials producing RSD values of less than 2%. The results indicate that SWE can be a potentially viable and efficient method for the sample preparation of whole, sliced, or ground pharmaceutical tablets, and further exploration of this approach is promising.