Methylolation and condensation products formed in caprolactam-formaldehyde reaction mixtures have been identified using nuclear magnetic resonance (NMR) and mass spectrometry (MS). Previously unreported side-products were also detected. All of the reaction products were separated by micellar electrokinetic chromatography (MEKC) and high performance liquid chromatography (HPLC), and the separation parameters, such as efficiency and distribution constants, obtained in the two techniques were compared. For quantification, the response factors for the monomers were determined using standard calibration and hydrolysis, whilst those for the condensation products were deduced from the values of the monomers. The accurate determination of the response factors was confirmed by checking the mass balance of a known mixture.

Supercritical fluid extraction (SFE) followed by packed column supercritical fluid chromatography with ultraviolet detection was evaluated as a quantitative method for determining 4 antifungals (fluconazole, tioconazole, hexaconazole, and UK- 47,265) in rodent diet. Chromatography was achieved with a cyano-bonded silica column, UV detection at 210 nm, and methanol-modified supercritical carbon dioxide as mobile phase. The effects of modifier concentration, temperature, and column pressure on antifungal retention time was studied. Off-line SFE was optimized at 2 spike levels, ranging from 0.5 to 10 g/kg, for each of the 4 antifungals. Average recoveries ranged from 79.0% for UK-47,265 to 96.5% for hexaconazole. Overall, the procedure provides a suitable method for analyzing antifungals in spiked rodent diet.

Propionamide-formaldehyde reaction products have been characterised using micellar electrokinetic chromatography (MEKC), HPLC-electrospray-MS (HPLC-ES-MS) and time-of-flight-MS (TOF-MS). HPLC-MS-MS was used to distinguish bel',,veen isomeric species. The MEKC separation of all reaction products was obtained with good resolution and efficiency. Comparison of water-micelle distribution constants (PMEKC) for propionamide-formaldehyde with those for caprolactam-formaldehyde reaction products suggests that the concentration of sodium dodecyl sulfate appropriate for use in MEKC is inversely related to PMEKO Quantification of all species containing one or I',,vo amide unitswas achieved using standard calibration, mass balance and the assumption of identical absorption coefficients for the same functional groups in monomers and dimers.