title: A validated1H NMR method for quantitative analysis of α-bisabolol in essential oils of Eremanthus erythropappus.
abstract: α-Bisabolol is a natural terpene produced by Eremanthus erythropappus and is widely used in cosmetics and pharmaceuticals due to its anti-inflammatory, antibacterial and antimycotic properties. Due to these applications, a control of composition and authenticity of commercial oils rich in this terpene is required, resulting in a demand for new methodologies for quality control. In this work a rapid and efficient method for quantification of α-bisabolol in the essential oil of E. erythropappus (candeia) using1H NMR was developed, validated and compared to gas chromatography (GC) method. The quantification of α-bisabolol by1H NMR was successfully achieved for most of the essential oil samples of E. erythropappus evaluated, except for those with a more complex composition. To circumvent this limitation a 2D NMR COSY contour map was used. This method proved to be a fast and efficient alternative, providing results with standard deviations SD<0.3%. All evaluated parameters (selectivity, linearity, accuracy/precision, repeatability, robustness and stability of analyte and internal standard in solution) gave satisfactory results. Using the1H NMR signals at 5.36 and 5.13ppm, the limit of detection (LOD) and limit of quantification (LOQ) were 0.26 and 2.59mg, respectively. The results obtained by the1H NMR method presented SD=0.59%, smaller than the value found for GC (SD=1.18%). Tukey tests have shown that the results obtained by1H NMR and COSY methodology are similar to the obtained by the traditional GC-FID technique using external and internal standardization and normalization with 95% confidence.
authors: Departament of Chemistry, Universidade Federal de Viçosa, Av. Peter Henry Holfs, S/N, Viçosa, MG, 36570-900 Brazil.
authors: Cristiane I
authors: CI
authors: Cerceau
authors: Departament of Chemistry, Universidade Federal de Viçosa, Av. Peter Henry Holfs, S/N, Viçosa, MG, 36570-900 Brazil; Departament of Chemistry, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627, Campus Pampulha, Belo Horizonte, MG, 31270-901 Brazil. Electronic address: lcab@ufmg.br.
authors: Luiz C A
authors: LCA
authors: Barbosa
authors: Departament of Chemistry, Universidade Federal de Viçosa, Av. Peter Henry Holfs, S/N, Viçosa, MG, 36570-900 Brazil.
authors: Elson S
authors: ES
authors: Alvarenga
authors: Laboratory of Nuclear Magnetic Resonance, Department of Chemistry, Universidade Federal de São Carlos, Via Washington Luís, Km 235, C.P. 676, São Carlos, SP, 13565-905 Brazil.
authors: Antonio G
authors: AG
authors: Ferreira
authors: Laboratory of Nuclear Magnetic Resonance, Department of Chemistry, Universidade Federal de São Carlos, Via Washington Luís, Km 235, C.P. 676, São Carlos, SP, 13565-905 Brazil.
authors: Sérgio S
authors: SS
authors: Thomasi
mesh_terms: D019659:Asteraceae; D008401:Gas Chromatography-Mass Spectrometry; D057230:Limit of Detection; D000081222:Monocyclic Sesquiterpenes; D009822:Oils, Volatile / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D012717:Sesquiterpenes / Q000032:analysis*
chemical_list: D000081222:Monocyclic Sesquiterpenes; D009822:Oils, Volatile; D012717:Sesquiterpenes; C004497:bisabolol
keywords: (1)H NMR; COSY; Essential oils; Gas chromatography; qNMR; α-Bisabolol