A simple, rapid, and accurate method has been developed for the determination of naphthaleneacetamide (NAAmide) residues in apples. After extraction with chloroform, separation is performed on an RP-8 high pressure liquid chromatographic column using acetonitrile-water (30 + 70) buffered to pH 3.5 at a flow rate of 1.7 mi/min. Either a variable wavelength ultraviolet detector set at 220 nm or a fluorometric detector can be used for quantitation. Average recoveries at the 0.01 and 0.1 ppm spiking levels were 83 and 89%, respectively. Incorporation into a previously described method for naphthaleneacetic acid (NAA) residues in apples has resulted in a procedure for the simultaneous determination of NAA and NAAmide.
A method is described for the determination of trace levels of N-nitroso-di-n-propylamine (NDPA) in trifluralin herbicide formulations. Following sample extraction, NDPA is separated on a silica gel column and determined by gas-liquid chromatography with a nitrogen-phosphorus detector (NPD). A comparison between the results obtained using this detection system and the thermal energy analyzer (TEA) for 0.5-5 ppm levels of NDPA in 17 samples showed no significant differences. Close agreement was also demonstrated with the results obtained by high resolution gas-liquid chromatography/mass spectrometry (GLC/MS). The minimum detectable amount of NDPA with the NPD was 5 pg, for the TEA system 50 pg, and for high resolution GLC/MS 100 pg. A number of other nitrosamines were detected by all systems in one sample but these were not fully characterized. The nitrogen-phosphorus detector is useful for monitoring traces of NDPA in trifluralin when preceded by cleanup on a silica gel column.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.