Combined multivariate data analysis of high-performance thin-layer chromatography fingerprints and direct analysis in real time mass spectra for profiling of natural products like propolis

Sophisticated statistical tools are required to extract the full analytical power from high-performance thin-layer chromatography (HPTLC). Especially, the combination of HPTLC fingerprints (image) with chemometrics is rarely used so far. Also, the newly developed, instantaneous direct analysis in real time mass spectrometry (DART-MS) method is perspective for sample characterization and differentiation by multivariate data analysis. This is a first novel study on the differentiation of natural products using a combination of fast fingerprint techniques, like HPTLC and DART-MS, for multivariate data analysis. The results obtained by the chemometric evaluation of HPTLC and DART-MS data provided complementary information. The complexity, expense, and analysis time were significantly reduced due to the use of statistical tools for evaluation of fingerprints. The approach allowed categorizing 91 propolis samples from Germany and other locations based on their phenolic compound profile. A high level of confidence was obtained when combining orthogonal approaches (HPTLC and DART-MS) for ultrafast sample characterization. HPTLC with selective post-chromatographic derivatization provided information on polarity, functional groups and spectral properties of marker compounds, while information on possible elemental formulae of principal components (phenolic markers) was obtained by DART-MS. (C) 2013 Elsevier B.V. All rights reserved.Peer-reviewed manuscript: [http://cherry.chem.bg.ac.rs/handle/123456789/3749

General criteria for selecting the conditions of the analysis by DART mass spectrometry

Проведено сопоставление результатов исследования состава и интенсивностей сигналов в масс-спектрах DART органических соединений при использовании нескольких типов масс-анализаторов и конфигураций вакуумного интерфейса между источником ионов и входом в масс-анализатор. На примере различных соединений установлена зависимость состава масс-спектров DART, полученных с использованием разных масс-анализаторов и условий эксперимента. Обсуждается роль состава и скорости потока газа-носителя, давления в вакуумном интерфейсе, температуры и состава атмосферы в области ионизации, присутствия добавки неона в гелии, параметров керамической трубки вакуумного интерфейса, напряжения на входе в масс-анализатор. Впервые сформулированы обобщенные рекомендации и критерии выбора условий регистрации масс-спектров DART в зависимости от аналитов, условий эксперимента, используемой технической базы.The results of studies of DART mass spectra for different organic compounds using different mass analyzers and configurations of the vacuum interface, located between the DART source and the entrance to the mass analyzer, are summarized. The dependence of the DART mass spectra on various experimental factors was studied using different mass analyzers and experimental conditions for organic compounds, belonging to different classes. The influence of composition and flow rate of the carrier gas, including the presence or absence of neon in helium, pressure in vacuum interface, temperature and composition of the atmosphere in the ionization region and in the surrounding area, parameters of the ceramic tube of the vacuum interface, and input voltage on the mass analyzer entrance is studied. For the first time, the general recommendations and criteria are outlined for selecting the conditions of registration of DART mass spectra depending on analytes, experimental parameters, and instrumental environment

Fast screening of hydro xymethylfurfural in honey using high-performance thin-layer chrometography

Впервые представлен способ быстрого определения (скрининга) оксиметилфурфурола в меде методом высокоэффективной тонкослойной хроматографии. Детектирование осуществляли методом денситометрического сканирования при измерении поглощения на длине волны 290 нм. При использовании предлагаемого подхода возможен одновременный анализ до 20 образцов, при этом длительность хроматографирования составляет около 5 минут.An approach for fast screening of hydroxymethylfurfural in honey by high-performance thin-layer chromatography is suggested for the first time. The detection was performed by densitometric scanning at 290 nm. Using this approach, it is possible to screen up to 20 samples simultaneously, and the separation takes just about 5 minutes

Fast classification of propolis samples by the principal component analysis of multivariate data (DART mass spectra) in Excel software

Впервые исследована возможность классификации образцов прополиса путем анализа многомерных данных масс-спектрометрии DART методом главных компонент при использовании надстройки Chemometrics Add-In для Microsoft Excel. Анализ осуществляли путем введения стеклянных капилляров, содержащих малую долю экстракта, в область ионизации, при этом длительность анализа одного образца составляла 30-40 с и могла быть сокращена до 8 с при использовании других устройств подачи образцов. Использование надстройки Chemometrics Add-In для Microsoft Excel позволило классифицировать образцы прополиса на два типа без использования специальных дорогостоящих статистических пакетов. Классификация на 87 % совпадала с классификацией тех же образцов путем визуального сравнения планарных хроматограмм, но позволяла предположить возможные молекулярные массы соединений-маркеров.The possibility for classification of propolis samples by multivariate data analysis of DART mass spectra by principal component analysis using the special add-in to the Microsoft Excel software «Chemometrics Add-In» was investigated for the first time. Propolis extracts were analyzed by introducing them on tips of glass capillaries to the ionization region. Duration of one analysis was 30-40 s and could be further reduced down to 8 s using other automatic sampling devices. Using «Chemometrics Add-In», the samples were classified in 2 main types without using any special expensive statistical packages. The classification of propolis samples in 87% coincided the classification of the same samples based on the visual comparison of planar chromatography images, but allowed to suggest the possible molecular masses of phenolic marker compounds

Letter: Characterization of volatile and semi-volatile compounds in green and fermented leaves of Bergenia crassifolia L. by gas chromatography-mass spectrometry and ID-CUBE direct analysis in real time-high resolution mass spectrometry

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