Simultaneous Determination of Theophylline and Caffeine by Proton Magnetic Resonance Spectroscopy Using Partial Least Squares Regression Techniques

Abstract

A 1 H-NMR procedure based on an analysis of its data by a multivariate calibration method was conducted for the simultaneous determination of theophylline and caffeine in synthetic and real samples. Partial least squares regression (PLS) was chosen as the calibration method. The methyl signals of theophilline at 3.36 and 3.54 ppm that overlapped with those of caffeine were significant characteristics which were employed in this study for their analyses. The proposed method was successfully applied to recovery studies of theophylline and caffeine from real tablet samples.

Rapid and Sensitive Determination of Methylxanthines in Commercial Brands of Tea Using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry

“…A variety of analytical techniques and sample preparation procedures have been developed and registered for determination and separation of these three methylxanthines in plants, environmental samples, drugs, food, and biological fluids. These proposed methods include UV-Vis spectrophotometry [22–24], thin-layer chromatography (TLC) [25], ion chromatography (IC) [26], FT-Raman spectrometry [27], IR spectrometry [28], capillary electrophoresis (CE) [29, 30], NMR spectroscopy [31], mass spectroscopy [32], gas chromatography-mass spectrometry (GC-MS) [15], high-performance thin-layer chromatography (HPTLC) [33, 34], voltammetry [35, 36], and high-performance liquid chromatography (HPLC) which was reported as the most frequently used approach [1, 2, 10, 37–49].…”

Theophyllıne: Adverse Effects, Poisoning and Treatment Approaches

“…Teofilin için ayrıca, biyolojik sıvılara ekstraksiyonunu takiben ince tabaka kromatografisi (İTK) ve plak okuyucu kullanarak yapılan bir nicel tayin yöntemi de tanımlanmıştır [75]. Teofilin analizi için florometrik bir ölçüm yöntemi ile [76] proton manyetik rezonans spektroskopisine ait bir yöntem bildirilmiştir [77]. Teofilinin biyolojik sıvılarda saptanması amacıyla, gaz-sıvı kromatografisi (GLC) [78], gaz kromatografisi-kütle spektroskopisi (GC-MS) [79][80], sıvı-kromatografi-kütle spektroskopisi (LC-MS) [81][82], yüksek basınçlı sıvı kromatografisi (YBSK) [83][84], yüksek performanslı sıvı kromatografisi-ince tabaka kromatografisi (YPSK-İTK) [85], çoklu enzim immonoassay tekniği (EMİT) [73,85] ve radyoimmonoassay (RIA) [86] yöntemleri kullanılmaktadır.…”

Evaluation of the total oxy-radical scavenging capacity of catechins isolated from green tea

“…The butanol extract (760 g) was subjected to silica gel column chromatography (70-230 mesh, 3 kg, 15.0 Â 100 cm) using a gradient of methylene chloride and methanol as the eluent to afford six fractions: f1 (106 g), f2 (5 g), f3 (27 g), f4 (300 g), f5 (152 g), and f6 (61 g). Fraction f1 (106 g) was allowed to stand at room temperature for several days and produced caffeine [24.7 g, white crystal, 1 H NMR (300 MHz, DMSO-d 6 ) d: 7.97 (1H, s), 3.86 (3H,s), 3.38 (3H,s), 3.19 (3H,s) 13 C NMR (125 MHz, DMSO-d 6 ) d: 154.5, 151.0, 148.1, 142.8, 106.6, 33.1, 29.3, 27.4] (Talebpour, Maesum, Jalali-Heravi, & Shamsipur, 2003). Fraction f2 was applied to a Sephadex LH-20 column (Ø = 2.0 Â 80 cm) eluted with 50% methanol to give three subfractions.…”