Cyclodextrin-assisted liquid-solid extraction for determination of the composition of jujube fruit using ultrahigh performance liquid chromatography with electrochemical detection and quadrupole time-of-flight tandem mass spectrometry.

A novel, simple and environmental friendly sample preparation technique based on the use of cyclodextrin has been developed for the extraction of phenolic compounds from jujube samples, the analytes being finally determined by ultrahigh performance liquid chromatography with electrochemical detection. Quadrupole time-of-flight tandem mass spectrometry was used to characterize the composition of jujube fruit. The present method exhibited higher efficiency for extracting phenolic compositions than Pharmacopoeia heat-reflux approach in term of peak areas. Moreover, compared with traditional ultrasound-assisted extraction, the developed methodology was found without the use of toxic organic solvent, meeting the principles of green chemistry. Validation experiments showed that the proposed method presented good linearity (r(2)>0.9970), satisfactory precision (RSD<7.55%), and high recovery (85.63-105.67%). The limits of detection were from 4.92ng/mL to 142.85ng/mL for eight phenolic compounds. Eventually, the optimized approach was successfully applied to the analysis of jujube fruit.

Characterization and determination of isomers in plants using trace matrix solid phase dispersion via ultrahigh performance liquid chromatography coupled with an ultraviolet detector and quadrupole time-of-flight tandem mass spectrometry.

Here, a novel ß-cyclodextrin (ß-CD) based trace matrix solid-phase dispersion (MSPD) method was developed to extract isomers from different honeysuckle samples using ultrahigh performance liquid chromatography. The structures of the analytes were characterized and determined via quadrupole time-of-flight tandem mass spectrometry and nuclear magnetic resonance. Under optimum conditions, 25mg of sample was dispersed with 75mg of ß-CD, and 0.5mL of methanol was used as the elution solvent. The proposed method produced a good linearity (r(2)>0.99) for the isomers, with limits of detection ranging from 1.62 to 3.33ng/mL. The average recovery values that were obtained from analyzing the spiked samples were calculated to be in the range of 87.04-105.20%. Moreover, the trace MSPD method required less reagents and a shorter extraction time in comparison with the traditional pharmacopoeia method and other reported approaches. The developed method was successfully applied for the determination of three real honeysuckle samples that were collected from different cultivated areas.

Effervescence and graphitized multi-walled carbon nanotubes assisted microextraction for natural antioxidants by ultra high performance liquid chromatography with electrochemical detection and quadrupole time-of-flight tandem mass spectrometry.

In this article, effervescence and graphitized multi-walled carbon nanotubes assisted microextraction was first developed for the extraction of antioxidants in hawthorn samples. The use of an effervescent tablet composed of sodium dihydrogen phosphate, sodium carbonate and micro-scale carboxyl graphitized multi-walled carbon nanotubes (extraction sorbent) was the core of the method. In this study, ultra high performance liquid chromatography coupled with electrochemical detection and quadrupole time-of-flight tandem mass spectrometry was performed for qualitative and quantitative analyses of target analytes in hawthorn foodstuffs. Several experimental factors, such as amount of effervescent salts, the sorbent, elution time and elution solvent, were systematically assessed. Under the optimized conditions, a good linearity with R values better than 0.9980 was obtained. The detection limits estimated at a signal-to-noise ratio of 3:1 were ranging from 0.01 to 0.18ng/mL. These results suggested that the proposed method could be an alternative and promising sample preparation tool in future food analysis.

Quantitative analysis of flavanones from citrus fruits by using mesoporous molecular sieve-based miniaturized solid phase extraction coupled to ultrahigh-performance liquid chromatography and quadrupole time-of-flight mass spectrometry.

An analytical procedure based on miniaturized solid phase extraction (SPE) and ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was developed and validated for determination of six flavanones in Citrus fruits. The mesoporous molecular sieve SBA-15 as a solid sorbent was characterised by Fourier transform-infrared spectroscopy and scanning electron microscopy. Additionally, compared with reported extraction techniques, the mesoporous SBA-15 based SPE method possessed the advantages of shorter analysis time and higher sensitivity. Furthermore, considering the different nature of the tested compounds, all of the parameters, including the SBA-15 amount, solution pH, elution solvent, and the sorbent type, were investigated in detail. Under the optimum condition, the instrumental detection and quantitation limits calculated were less than 4.26 and 14.29ngmL(-1), respectively. The recoveries obtained for all the analytes were ranging from 89.22% to 103.46%. The experimental results suggested that SBA-15 was a promising material for the purification and enrichment of target flavanones from complex citrus fruit samples.

Application of a highly sensitive magnetic solid phase extraction for phytochemical compounds in medicinal plant and biological fluids by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

A highly sensitive method using reduced graphene oxide with iron oxide (rGO/Fe3 O4 ) as the sorbent in magnetic SPE has been developed for the purification of five anthraquinones (emodin, rhein, aloeemodin, physcion, and chrysophanol) in rhubarb and rat urine by ultra-HPLC coupled with quadrupole TOF/MS. The extraction was accomplished by adding trace amount rGO/Fe3 O4 suspension to 200 mL of aqueous mixture, and the excellent adsorption capacity of the nanoparticles was fully demonstrated in this procedure. Under the optimized conditions, the calibration curves were linear in the concentration range of 0.05-27.77 ng/mL with correlation coefficients varying from 0.9902 to 0.9978. The LODs ranged from 0.28 to 58.99 pg/mL. The experimental results indicated that the proposed method was feasible for the analysis of anthraquinones in rhubarb and urine samples.