This paper describes the application of thermogravimetry including conventional thermobalance and standard sample holders for the estimation of vapor pressure and related thermodynamic properties of a potent narcotic analgesic, fentanyl . For this study, benzoic acid was used as a reference material to calibrate the thermogravimetric analysis (TGA) instrument and experimental conditions used. The relationship between the isothermal sublimation rates of benzoic acid determined at different temperatures and the corresponding literature vapor pressure values was established, and the correlation equation thus obtained was used for the estimation of vapor pressure of fentanyl. By adopting this procedure, the vapor pressure of fentanyl was estimated at different temperatures from T ) (423.15 to 493.15) K. Extrapolation of the measured data to T ) 298.15 K gave the vapor pressure of subcooled fentanyl and estimated it to be (4.6 ( 2.7) • 10 -6 Pa. The corresponding solid phase vapor pressure of fentanyl was calculated to be (5.9 ( 4.7) • 10 -7 Pa after taking the enthalpy of fusion into consideration. Related thermodynamic properties, viz., enthaply of vaporization and normal boiling points, were also estimated from the vapor pressure-temperature curve.
Fentanyl is a very potent synthetic narcotic analgesic. Because of its strong sedative properties, it has become an analogue of illicit drugs such as heroin. Its unambiguous detection and identification in environmental samples can be regarded as strong evidence of its illicit preparation. In this paper we report application of single-drop microextraction (SDME) for analysis of water samples spiked with fentanyl. Experimental conditions which affect the performance of SDME, for example the nature of the extracting solvent, sample stirring speed, extraction time, ionic strength, and solution pH, were optimized. The method was found to be linear in the concentration range 0.10-10 ng mL(-1). The limits of quantitation and detection of the method were 100 pg mL(-1) and <75 pg mL(-1), respectively. This technique is superior to other sample-preparation techniques because of the simple experimental set-up, short analysis time, high sensitivity, and minimum use of organic solvent.
Narcotic analgesics of the fentanyl class are characterized by high potency and relatively short duration of action. These compounds nowadays have become a substitute for heroine and are highly addictive for abusers. Herein, we report retention indices of fentanyl and its eighteen analogues relative to the homologous n-alkane series. These values are determined on a moderately polar BP-5 capillary column under programmed temperature and isothermal chromatographic conditions. The analogues differ in the substituent attached to the piperidine ring nitrogen, and retention indices are found to vary according to the nature of the substituent. The effects of chromatographic conditions like temperature programming rate, carrier gas flow rate, and oven temperature are studied. Retention indices are also determined on a non-polar BP-1 column to study the influence of stationary phase polarity. Standard deviation of all the RI values is less than one index unit.
This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation of the reagent in current research Selectfluor (F-TEDA-BF 4 ) C 7 H 14 B 2 ClF 9 N 2 Compiled by Laxmi Manral Laxmi Manral was born in 1981. She received her B.Sc. in 2002 from Delhi University and M.Sc. in Organic Chemistry in 2004 from Kumaun University, Nanital, India. She joined DRDE in 2005 as a JRF and currently pursuing her Ph.D. under the tutelage of Dr. R. C. Malhotra, Joint Director of DRDE. Her present research is focused on narcotic analgesics; synthesis and stability studies.
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