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Liquid chromatography with diode array detection combined with spectral deconvolution for the analysis of some diterpene esters in Arabica coffee brew

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JOURNAL OF SEPARATION SCIENCE 2015年第4期38卷 612-620页

作者： Erny, Guillaume L. Moeenfard, Marzieh Alves, Arminda Univ Porto LEPABE Fac Engn P-4200465 Oporto Portugal

In this manuscript, the separation of kahweol and cafestol esters from Arabica coffee brews was investigated using liquid chromatography with a diode array detector. When detected in conjunction, cafestol, and kahweol esters were eluted together, but, after optimization, the kahweol esters could be selectively detected by setting the wavelength at 290 nm to allow their quantification. Such an approach was not possible for the cafestol esters, and spectral deconvolution was used to obtain deconvoluted chromatograms. In each of those chromatograms, the four esters were baseline separated allowing for the quantification of the eight targeted compounds. Because kahweol esters could be quantified either using the chromatogram obtained by setting the wavelength at 290 nm or using the deconvoluted chromatogram, those compounds were used to compare the analytical performances. Slightly better limits of detection were obtained using the deconvoluted chromatogram. Identical concentrations were found in a real sample with both approaches. The peak areas in the deconvoluted chromatograms were repeatable (intraday repeatability of 0.8%, interday repeatability of 1.0%). This work demonstrates the accuracy of spectral deconvolution when using liquid chromatography to mathematically separate coeluting compounds using the full spectra recorded by a diode array detector.

关键词： Cafestol esters diode array detection Kahweol esters Spectral deconvolution

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Rapid quantitative analysis of individual anthocyanin content based on high-performance liquid chromatography with diode array detection with the pH differential method

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JOURNAL OF SEPARATION SCIENCE 2014年第18期37卷 2535-2544页

作者： Wang, Huayin Zhejiang Sci Tech Univ Hangzhou 310018 Zhejiang Peoples R China

A new quantitative technique for the simultaneous quantification of the individual anthocyanins based on the pH differential method and high-performance liquid chromatography with diode array detection is proposed in this paper. The six individual anthocyanins (cyanidin 3-glucoside, cyanidin 3-rutinoside, petunidin 3-glucoside, petunidin 3-rutinoside, and malvidin 3-rutinoside) from mulberry (Morus rubra) and Liriope platyphylla were used for demonstration and validation. The elution of anthocyanins was performed using a C-18 column with stepwise gradient elution and individual anthocyanins were identified by high-performance liquid chromatography with tandem mass spectrometry. Based on the pH differential method, the high-performance liquid chromatography peak areas of maximum and reference absorption wavelengths of anthocyanin extracts were conducted to quantify individual anthocyanins. The calibration curves for these anthocyanins were linear within the range of 10-5500 mg/L. The correlation coefficients (r(2)) all exceeded 0.9972, and the limits of detection were in the range of 1-4 mg/L at a signal-to-noise ratio >= 5 for these anthocyanins. The proposed quantitative analysis was reproducible with good accuracy of all individual anthocyanins ranging from 96.3 to 104.2% and relative recoveries were in the range 98.4-103.2%. The proposed technique is performed without anthocyanin standards and is a simple, rapid, accurate, and economical method to determine individual anthocyanin contents.

关键词： Anthocyanins diode array detection High-performance liquid chromatography Mulberry pH differential method

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Liquid chromatography with diode array detection and multivariate curve resolution for the selective and sensitive quantification of estrogens in natural waters

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ANALYTICA CHIMICA ACTA 2014年 835卷 19-28页

作者： Perez, Rocio L. Escandar, Graciela M. Univ Nacl Rosario Fac Ciencias Bioquim & Farmaceut CONICET UNR Inst Quim Rosario RA-2000 Rosario Santa Fe Argentina

Following the green analytical chemistry principles, an efficient strategy involving second-order data provided by liquid chromatography (LC) with diode array detection (DAD) was applied for the simultaneous determination of estriol, 17 beta-estradiol, 17 alpha-ethinylestradiol and estrone in natural water samples. After a simple pre-concentration step, LC-DAD matrix data were rapidly obtained (in less than 5 min) with a chromatographic system operating isocratically. Applying a second-order calibration algorithm based on multivariate curve resolution with alternating least-squares (MCR-ALS), successful resolution was achieved in the presence of sample constituents that strongly coelute with the analytes. The flexibility of this multivariate model allowed the quantification of the four estrogens in tap, mineral, underground and river water samples. Limits of detection in the range between 3 and 13 ng L-1, and relative prediction errors from 2 to 11% were achieved. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Liquid chromatography diode array detection Multivariate curve resolution Estrogens Natural waters

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High-performance liquid chromatography with diode-array detection cotinine method adapted for the assessment of tobacco smoke exposure

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JOURNAL OF SEPARATION SCIENCE 2014年第12期37卷 1404-1410页

作者： Bartolome, Monica Gallego-Pico, Alejandrina Huetos, Olga Castano, Argelia Inst Salud Carlos III Natl Ctr Environm Hlth Majadahonda Spain Univ Nacl Educ Distancia Dept Analyt Sci Fac Sci Madrid Spain

Smoking is considered to be one of the main risk factors for cancer and other diseases and is the second leading cause of death worldwide. As the anti-tobacco legislation implemented in Europe has reduced secondhand smoke exposure levels, analytical methods must be adapted to these new levels. Recent research has demonstrated that cotinine is the best overall discriminator when biomarkers are used to determine whether a person has ongoing exposure to tobacco smoke. This work proposes a sensitive, simple and low-cost method based on solid-phase extraction and liquid chromatography with diode array detection for the assessment of tobacco smoke exposure by cotinine determination in urine. The analytical procedure is simple and fast (20 min) when compared to other similar methods existing in the literature, and it is cheaper than the mass spectrometry techniques usually used to quantify levels in nonsmokers. We obtained a quantification limit of 12.30 g/L and a recovery of over 90%. The linearity ranges used were 12-250 and 250-4000 g/L. The method was successfully used to determine cotinine in urine samples collected from different volunteers and is clearly an alternative routine method that allows active and passive smokers to be distinguished.

关键词： Cotinine diode array detection Liquid chromatography Solid-phase extraction Urine

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Combining poly(dimethyldiphenylsiloxane) and nitrile phases for improving the separation and quantitation of benzalkonium chloride homologues: In-tube solid phase microextraction-capillary liquid chromatography-diode array detection-mass spectrometry for analyzing industrial samples

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JOURNAL OF CHROMATOGRAPHY A 2013年 1297卷 226-230页

作者： Prieto-Blanco, M. C. Moliner-Martinez, Y. Campins-Falco, P. Univ A Coruna Fac Ciencias Dept Quim Analit E-15071 La Coruna Spain Univ Valencia Fac Quim Dept Quim Analit E-46100 Valencia Spain

The retention and separation of four homologues of benzalkonium chloride (alkyl (C-12, C-14, C-16, C-18) dimethylbenzylammonium chloride) have been studied in poly(dimethyldiphenylsiloxane) (TRB) and nitrile capillary phases, respectively. Under the optimized conditions (50% acetonitrile in processed samples, 35% of diphenyl content of the TRB, capillary length 43 cm and water: methanol 60:40 as replacing solvent), the extraction efficiency was similar for all the homologues with satisfactory reproducibility and independently of the amount and proportion of homologues. Industrial samples with high viscosity or with complex composition and washes waters have been analyzed without previous treatment. The coupling of IT-SPME-CapLC-DAD to MS detection allowed the determination of the minority homologues (C-16 and C-18) in the industrial samples and washes waters. No matrix effect was found. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Benzalkonium Chloride In-tube solid phase microextraction Capillary LC diode array detection MS detection Industrial and washes water samples

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Monitoring of cyanotoxins in water from hypersaline microalgae colonies by ultra high performance liquid chromatography with diode array and tandem mass spectrometry detection following salting-out liquid-liquid extraction

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JOURNAL OF CHROMATOGRAPHY A 2019年 1608卷 460409-460409页

作者： Hemmati, Maryam Tejada-Casado, Carmen Lara, Francisco J. Garcia-Campana, Ana M. Rajabi, Maryam Del Olmo-Iruela, Monsalud Univ Granada Dept Analyt Chem Av Fuente Nueva S-N E-18071 Granada Spain Semnan Univ Dept Chem Semnan *** Iran

In this study two different analytical approaches have been developed to determine the presence of several cyanotoxins in saline water samples from a continental salt marsh. A salting-out assisted liquid-liquid extraction (SALLE) has been used in combination with ultra-high performance liquid chromatography-tandem mass spectrometry and UV-diode array detection (UHPLC-MS/MS and UHPLC-DAD). The target analytes are eight microcystins named MC-RR, MC-YR, MC-LR, MC-WR, MC-LA, MC-LY, MC-LW, MC-LF and nodularin (NOD), covering a wide range of polarities. The separation was achieved using a Zorbax Eclipse Plus RRHD C18 column (50 x 2.1 mm, 1.8 mu m) in less than 7.5 and 5.5 min for UV and MS/MS detection, respectively. The mobile phase used consisted of water (solvent A) and acetonitrile (MeCN) (solvent B), both containing 0.01% of formic acid for DAD and 0.4% of formic acid for MS/MS detection, at a flow rate of 0.4 mL min(-1). The temperature of the column was set at 25 degrees C and 20 mu L of sample were injected. The main parameters affecting the SALLE procedure were studied and the following optimum values were obtained: neutral pH, 2 mL of acetonitrile as extraction solvent and 1.2 g of ammonium sulfate as salting-out agent for 4 mL of water sample. The validation protocols for both methods were accomplished with real water samples obtaining LODs ranging from 1.0 to 3.4 mu g L-1 and 0.02 to 0.11 mu g L-1 for DAD and MS/MS respectively. Although the SALLE-UHPLC-DAD methodology is easier and cheaper than UHPLC-MS/MS significantly better detection limits were achieved with tandem mass spectrometry as well as allowing for unambiguous identification. Extraction recoveries were higher than 77.0% (except for MC-RR and NOD which were 53.2% and 54.3, respectively) with satisfactory inter-day and intra-day precisions (RSD below 13.3%). (C) 2019 Elsevier B.V. All rights reserved.

关键词： Cyanotoxins diode array detection Salting-out assisted liquid-liquid extraction Saline waters Tandem mass spectrometry Ultra-high performance liquid chromatography

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A stability-indicating HPLC method for estimation of doxylamine succinate in tablets and characterization of its major alkaline stress degradation product

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FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2021年第1期7卷 137页

作者： Harde, Minal T. Lakade, Sameer H. PESs Modern Coll Pharm Dept Pharmaceut Chem Sect 21 Pune MS India Rasiklal M Dhariwal Inst Pharmaceut Educ & Res Dept Pharmaceut Pune MS India

Background: A new selective rapid RP-HPLC-DAD method was developed and evaluated for the quantification of doxylamine succinate (DOX) in bulk and pharmaceutical dosage form. The separation of DOX at different degradation conditions was achieved with a Kromasil C-18 (4.6 x 250 mm, 5-mu m particle size). The mobile phase employed comprised of phosphate buffer (pH 3.5) and methanol in the ratio of 45:55 v/v. The flow rate was kept maintained at 1.0 ml/min and eluents were detected at 262 nm. The drug was subjected to different stress conditions like acid, base, neutral, hydrolysis, oxidation, photolysis, and thermal degradation. The analytical performance of the proposed HPLC method was thoroughly validated in terms of linearity, precision, accuracy, specificity, robustness, detection, and quantification limits. Results: The method produces linear responses that were found in the range of 10-50 mu g/ml. The regression equation was found to be Y = 42984x - 10260. The correlation coefficient was found to be 0.9998. The LOD and LOQ for DOX were found to be 0.96 and 3.28 mu g/ml, respectively. The short-term solution stability of DOX (100 mu g/ ml) was evaluated under (25 +/- 2 degrees C) storage condition and found to be 98.82 to 101%. The percentage recovery for DOX was in the range of 99.73 to 99.91%. The obtained results of the stress degradation study and peak purity data indicate the potential of the developed HPLC method to resolve degradants from DOX peak. The major alkaline degradation product was isolated using preparative chromatographic technique and extensive FT-IR was performed to ascertain the structure of the alkaline degradant. Conclusion: It was concluded that the proposed method was simple, sensitive, accurate, cost-effective, and less time-consuming for the quantification of DOX. This method was successfully utilized for stability testing of commercially available DOX tablets. Hence, the proposed method can be applied for routine quality control of DOX

关键词： Doxylamine succinate Stress study RP-HPLC diode array detection ICH

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Antioxidant and Antibacterial Properties of Norway Spruce (Picea abies H. Karst.) and Eastern Hemlock (Tsuga canadensis (L.) Carriere) Cone Extracts

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FORESTS 2021年第9期12卷 1189页

作者： Hofmann, Tamas Albert, Levente Nemeth, Laszlo Vrsanska, Martina Schlosserova, Nikola Voberkova, Stanislava Visi-Rajczi, Eszter Univ Sopron Inst Chem H-9400 Sopron Hungary Univ Sopron Inst Math H-9400 Sopron Hungary Mendel Univ Brno Dept Chem & Biochem CZ-61300 Brno Czech Republic

According to recent studies, Norway spruce cones and eastern hemlock cones possess exceptionally high antioxidant capacities;however, the antioxidant efficiency of extractives and their bioactive effects have yet to be investigated in detail. The present article utilizes state-of-the art analytical chemical methodology and chemometric evaluation to reveal cone extractives with the highest antioxidant potential, accounting for possible bioactive effects. Antioxidant properties were determined by the Ferric reducing antioxidant power (FRAP) assay and the Folin-Ciocalteu's total phenol content (TPC) assay. Structure and relative polyphenol concentrations were determined using liquid chromatography/diode array detection/tandem mass spectrometry. The antibacterial testing was conducted using Staphylococcus aureus and Escherichia coli strains. Using correlation analysis and factor analysis, a scoring evaluation was implemented to determine and compare the antioxidant efficiency of extractives. In Norway spruce, piceatannol-O-hexoside and coumaric acid derivatives were found to be the most powerful antioxidants, while in eastern hemlock, kaempferol glycosides were the most powerful. The antibacterial test did not show any promising antimicrobial activity against E. coli, although a visible inhibitory effect on S. aureus strain was observed.

关键词： Norway spruce eastern hemlock polyphenols antioxidant capacity chemometrics high-performance liquid chromatography diode array detection mass spectrometry antibacterial activity

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Analysis of Phlebodium decumanum Fronds by High-Performance Liquid Chromatography by Ultraviolet-Visible and Quadrupole Time-of-Flight Tandem Mass Spectrometry (HPLC-UV-VIS-QTOF-MS/MS)

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ANALYTICAL LETTERS 2019年第13期52卷 2107-2132页

作者： Martin-Pozo, Laura Zafra-Gomez, Alberto Cantarero-Malagon, Samuel Luis Vilchez, Jose Univ Granada Res Grp Analyt Chem & Life Sci Dept Analyt Chem Granada Spain Univ Granada Ctr Sci Instrumentat Granada Spain

Phlebodium decumanum (P. decumanum), together with other tropical ferns commonly known as Calaguala, have been empirically applied since ancient times to ameliorate inflammatory disorders, skins diseases and even cancer. There are evidences of antineoplastic potential and anti-inflammatory, immunomodulatory and antioxidant properties of the extract. Preliminary studies have also shown direct antitumor activity of the extracts. In the present article, the phytochemical composition of a hydro-ethanolic extract of P. decumanum is investigated using high-performance liquid chromatography (HPLC) with ultraviolet-visible (UV-vis) diode array detection (DAD) and electrospray ionization (ESI) quadrupole time-of-flight tandem mass spectrometry (QTOF-MS/MS) detection. First, the chromatographic profile is established as a representative fingerprint of the compounds extracted from the fern. Then, a total of 122 chemicals, including 23 flavonoids, 47 phenolic acids (34 hydroxycinnamic acids and 13 hydroxybenzoic acids), 9 amino and amino-sugar derivatives, 24 organic acids and their derivatives, and other metabolites, have been characterized. Moreover, 12 unknown compounds were also detected, providing the first comprehensive characterization available on the phytochemical composition of the leaves of P. decumanum.

关键词： Active compounds electrospray ionization diode array detection high performance liquid chromatography Phlebodium decumanum phytochemical profile ultraviolet-visible spectroscopy quadrupole time-of-flight tandem mass spectrometry

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β-Cyclodextrin polymer@Fe₃O₄ based magnetic solid-phase extraction coupled with HPLC for the determination of benzoylurea insecticides from honey, tomato, and environmental water samples

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JOURNAL OF SEPARATION SCIENCE 2018年第7期41卷 1539-1547页

作者： Liang, Xinyu Ma, Ruiyang Hao, Lin Wang, Chun Wu, Qiuhua Wang, Zhi Hebei Agr Univ Coll Sci Baoding 071001 Peoples R China Hebei Agr Univ Coll Landscape & Travel Baoding Peoples R China

In this work, a magnetic beta-cyclodextrin polymer was successfully prepared and used as an adsorbent for the magnetic solid-phase extraction of six benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, flufenoxuron, and chlorfluazuron) from honey, tomato, and environmental water samples. The influence of the main experimental conditions on the extraction was studied. Under the optimized conditions, the beta-cyclodextrin polymer@Fe3O4 showed an excellent extraction performance for the benzoylurea insecticides. A good linearity was obtained for the analytes in the range of 3.0-800 ng/g for honey samples, 0.3-160 ng/g for tomato samples, and 0.1-80.0 ng/mL for water samples, with the correlation coefficients above 0.9998. Satisfactory repeatabilities were achieved, with the relative standard deviations less than 5.7%. The limits of detection (S/N = 3) of the method for the benzoylurea insecticides were 0.2-0.8 ng/g for honey samples, 0.04-0.10 ng/g for tomato samples, and 0.02-0.05 ng/mL for water samples. The method was successfully used for the determination of the six benzoylurea insecticides residues in honey, tomato, and environmental water samples with a satisfactory result.

关键词： benzoylurea insecticides diode array detection high performance liquid chromatography magnetic beta-cyclodextrin polymers magnetic solid-phase extraction

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