Chromatography has long been, and remains, the workhorse of downstream processing in the production of biopharmaceuticals. As bioprocessing has matured, there has been a growing trend toward seeking ...a detailed fundamental understanding of the relevant unit operations, which for some operations include the use of mechanistic modeling in a way similar to its use in the conventional chemical process industries. Mechanistic models of chromatography have been developed for almost a century, but although the essential features are generally understood, the specialization of such models to biopharmaceutical processing includes several areas that require further elucidation. This review outlines the overall approaches used in such modeling and emphasizes current needs, specifically in the context of typical uses of such models; these include selection and improvement of isotherm models and methods to estimate isotherm and transport parameters independently. Further insights are likely to be aided by molecular-level modeling, as well as by the copious amounts of empirical data available for existing processes.
Phenolic compounds represent a class of highly complex naturally occurring molecules that possess a range of beneficial health properties. As a result, considerable attention has been devoted to the ...analysis of phenolics in a variety of samples. HPLC is the workhorse method for phenolic separation. However, conventional HPLC methods provide insufficient resolving power when faced with the complexity of real-world phenolic fractions. This limitation has been traditionally circumvented by extensive sample fractionation, multiple analysis methods and/or selective detection strategies. On the other hand, there is an increasing demand for improved throughput and resolving power from the chromatographic methods used for phenolic analyses. Fortunately, during the last decade, a number of important technological advances in LC have demonstrated significant gains in terms of both speed and resolution. These include ultra high-pressure liquid chromatography (UHPLC), high-temperature liquid chromatography (HTLC), multi-dimensional separations as well as various new stationary phase chemistries and morphologies. In recent years, these technologies have also found increasing application for phenolic analysis. This review seeks to provide an updated overview of the application of recent advances in HPLC to phenolic separation, with the emphasis on how these methodologies can contribute to improve performance in HPLC analysis of phenolics.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS) variants currently represent the best tools to tackle the challenges of complexity and lack of ...comprehensive coverage of the metabolome. UHPLC offers flexible and efficient separation coupled with high-sensitivity detection via HRMS, allowing for the detection and identification of a broad range of metabolites. Here we discuss current common strategies for UHPLC-HRMS-based metabolomics, with a focus on expanding metabolome coverage.
Today scientists must deal with complex samples that either cannot be adequately separated using one-dimensional chromatography or that require an inordinate amount of time for separation. For these ...cases we need two-dimensional chromatography because it takes far less time to generate a peak capacity
n
c
twice in a row than to generate a peak capacity
n
c
2
once. Liquid chromatography has been carried out successfully on thin layers of adsorbents and along tubes filled with various adsorbents. The first type of separation sorts out the sample components in a physical separation space that is the layer of packing material. The analysis time is the same for all the components of the sample while their migration distance increases with decreasing retention. The resolution between two components having a certain separation factor (
α
) increases with increasing migration distance, i.e., from the strongly to the weakly retained compounds. In the second type of separation, the sample components are eluted from the column and separated in the time space, their migration distances are all the same while their retention times increase from the unretained to the strongly retained compounds. Separation efficiency varies little with retention, as long as the components are eluted from the column. We call these two types of separation the chromatographic separations in space (LC
x
) and the chromatographic separations in time (LC
t
), respectively. In principle, there are four ways to combine these two modes and do two-dimensional chromatographic separations,
LC
t
×
LC
t
,
LC
x
×
LC
t
,
LC
t
×
LC
x
, and
LC
x
×
LC
x
. We review, discuss and compare the potential performance of these combinations, their advantages, drawbacks, problems, perspectives and results. Currently, column-based combinations (
LC
t
×
LC
t
) are the most actively pursued. We suggest that the combination
LC
x
×
LC
t
shows exceptional promise because it permits the simultaneous second-dimension separations of all the fractions separated in the first-dimension, thus providing remarkable time saving.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Mercury (Hg) and its compounds are much concerned for their high toxicity and wide presence in the environment. Since the toxicity of Hg is species dependent, various methods have been developed for ...the speciation analysis of Hg. This review focus on the determination and speciation analysis of Hg chemical species in water, sediment, and soil samples. Recent developments on sample pre-treatment and extraction/pre-concentration, separation, and quantification of Hg chemical species, and associated analytical challenges have been reviewed and briefly discussed based on recent reports.
Current studies related to lipid identification and determination, or lipidomics in biological samples, are one of the most important issues in modern bioanalytical chemistry. There are many articles ...dedicated to specific analytical strategies used in lipidomics in various kinds of biological samples. However, in such literature, there is a lack of articles dedicated to a comprehensive review of the actual analytical methodologies used in lipidomics. The aim of this article is to characterize the lipidomics methods used in modern bioanalysis according to the methodological point of view: (1) chromatography/separation methods, (2) spectroscopic methods and (3) mass spectrometry and also hyphenated methods. In the first part, we discussed thin layer chromatography (TLC), high-pressure liquid chromatography (HPLC), gas chromatography (GC) and capillary electrophoresis (CE). The second part includes spectroscopic techniques such as Raman spectroscopy (RS), Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR). The third part is a synthetic review of mass spectrometry, matrix-assisted laser desorption/ionization (MALDI), hyphenated methods, which include liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS) and also multidimensional techniques. Other aspects are the possibilities of the application of the described methods in lipidomics studies. Due to the fact that the exploration of new methods of lipidomics analysis and their applications in clinical and medical studies are still challenging for researchers working in life science, we hope that this review article will be very useful for readers.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Chiral compounds are ubiquitous in nature and play a pivotal role in biochemical processes, in chiroptical materials and applications, and as chiral drugs. The analysis and determination of the ...enantiomeric ratio (er) of chiral compounds is of enormous scientific, industrial, and economic importance. Chiral separation techniques and methods have become indispensable tools to separate chiral compounds into their enantiomers on an analytical as well on a preparative level to obtain enantiopure compounds. Chiral gas chromatography and high‐performance liquid chromatography have paved the way and fostered several research areas, that is, asymmetric synthesis and catalysis in organic, medicinal, pharmaceutical, and supramolecular chemistry. The development of highly enantioselective chiral stationary phases was essential. In particular, the elucidation and understanding of the underlying enantioselective supramolecular separation mechanisms led to the design of new chiral stationary phases. This review article focuses on the development of chiral stationary phases for gas chromatography. The fundamental mechanisms of the recognition and separation of enantiomers and the selectors and chiral stationary phases used in chiral gas chromatography are presented. An overview over syntheses and applications of these chiral stationary phases is presented as a practical guidance for enantioselective separation of chiral compound classes and substances by gas chromatography.
This review article focuses on the development of chiral stationary phases for gas chromatography. The fundamental mechanisms of the recognition and separation of enantiomers and the selectors and chiral stationary phases used in chiral gas chromatography are presented. An overview over syntheses and applications of these chiral stationary phases is presented as a practical guidance for enantioselective separation of chiral compound classes and substances by gas chromatography.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Bioprofiling on the planar chromatogram with in situ biological/enzymatic assays is a powerful bioanalytical screening tool for the nontargeted detection of known and especially unknown/unidentified ...bioactive compounds directly in multicomponent mixtures (e.g., foods, spices, and botanicals). However, together with the bioactive zone, the adsorbed bioassay medium is eluted into the mass spectrometer (MS) and interfering with evaluation. Another sample track without bioassay has thus been handled in parallel. Hence, for a direct zone elution from the bioautogram, different setups were investigated to reduce the impact of the bioassay medium load. A biocompatible filter, orthogonal reversed-phase/cation-exchange columns (RP/IEX-HPLC), UV/vis detector, and a Rheodyne valve were installed between the zone eluting interface (after normal-phase high-performance thin-layer chromatography-multi-imaging-bioassay, NP-HPTLC-UV/vis/FLD-bioassay) and the MS. For the negative electrospray ionization mode (ESI–), an RP-18e-HPLC column and valve switch were exploited. After gradient optimization, the RP-column retarded the eluted polar compounds and split-off the salts of the bioassay medium in the first minutes. This reduced the bioassay load and separated analyte signals thereof. However, most bioassay medium mass signals were predominantly detectable in ESI+-MS. Here, the reduction of bioassay matrix signals was achieved by integrating a mixed-mode RP/IEX column. Finally, two different superhyphenations were successfully proven: NP-HPLC-UV/vis/FLD-bioassay-RP-HPLC-UV/vis-ESI–-MS with a valve switch and NP-HPLC-UV/vis/FLD-bioassay-RP/IEX-HPLC-UV/vis-ESI±-MS with or without it. Although the original bioprofiling (NP-HPTLC-UV/vis/FLD-bioassay) was prolonged from 3 to 13 min per sample, such superhyphenations covering chemistry/biology/mass spectrometry are considered as an efficient nontarget bioanalytical tool for fast evaluation of complex samples.
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IJS, KILJ, NUK, PNG, UL, UM
The chemical composition and biological activities of Balanophora fungosa var. globosa (BFG) were studied for the first time. Also, the chemical composition of some other Balanophora species was ...established for comparison. Phenolic compounds isolariciresinol, gallic acid, pinoresinol, methyl caffeate, and epipinoresinol-4-O-beta-D-glucopyranoside were isolated from Balanophora fungosa var. globosa collected in Vietnam and identified by the NMR analysis. Some in vitro biological activities of the isolated compounds, including the inhibitory effect on NO production and cytotoxic effects, were evaluated. The chromatographic methods were developed to determine the chemical fingerprints of BFG and its very close taxon subsp. indica (Arn.) B. Hansen (BFI), also of the two new species recently recorded for the flora of Vietnam Balanophora tobiracola Makino (BT) and Balanophora subcupularis P.C. Tam (BS). Among the isolated compounds, isolariciresinol showed a moderate inhibitory effect on NO production (I% = 56.02 at concentration of 100 microg/mL), while gallic acid at concentration of 100 microg/mL demonstrated moderate cytotoxicity against cancer cell lines MCF-7 (human breast carcinoma) and PC3 (human prostate gland carcinoma). The HPTLC analysis showed similarities in the chemical compositions of BFG and BFI, as well as the difference between their compositions and these of BT and BS. O-caffeoyl-O-galloyl-glucoside I, caffeic acid glucoside, O-caffeoyl-di-galloyl-beta-D-glucoside V, and 1-O-caffeoyl-3-O-galloyl-4,6-HHDP-beta-D-glucoside as principal compounds were identified among 31 phenolic substances of BFI and BFG by using HPLC-MS/MS. Key words: anti-cancer activity, anti-inflammatory activity, Balanophora fungosa subsp. indica, Balanophora subcupularis, Balanophora tobiracola, isolation. Vietnamis kasvava taime Balanophora fungosa varietas globosa keemilist koostist ja bioloogilist aktiivsust uuriti selles töös esmakordselt. Samuti võrreldi mõnede Balanophora perekonna liikide keemilist koostist. Fenoolsed ühendid isolaritsiresinool (1), gallushape (2), pinoresinool (3), metüülkafeaat (4) ja epipinoresinool-4-O-beta-D-glukopüranosiid (5) isoleeriti ning identifitseeriti NMR-analüüsi tulemusel Vietnamist kogutud B. fungosa varietas globosa droogiproovi põhjal. Isoleeritud koostisainete mõned toimed, nagu NO produktsiooni inhibeeriv ja rakutoksiline efekt, tehti kindlaks in vitro. Töötati välja kromatograafilised meetodid B. fungosa varietas globosa ja sellele väga lähedase taksoni B. fungosa subsp. indica (Arn.) B. Hansen, aga ka Vietnamist hiljuti avastatud kahe uue liigi Balanophora tobiracola Makino ja Balanophora subcupularis P.C. Tam (BS) omavaheliseks eristamiseks. Isoleeritud komponentidest näitas isolarit-siresinool keskmise tasemega NO produktsioon I inhibeerivat efekti (I% = 56,02 kontsentratsioonil 100 microg/mL), samas oli gallushappel kontsentratsiooni 100 microg/mL korral keskmine rakutoksiline aktiivsus inimese rinnakartsinoomi rakkudesse (MCF-7) ja eesnäärmekartsinoomi rakkudesse (PC3). HPTLC-analüüs näitas sarnasust B. fungosa varietas globosa ja B. fungosa subsp. indica keemilise koostise vahel, mis aga oli erinev B. tobiracola ja B. subcupularis'e fütokeemilise profiili puhul. Kahes sarnase koostisega taksonis identifitseeriti HPLC-MS/MS-meetodil 31 fenoolset ühendit, millest peamised on O-kafeoüül-O-galloüülglükosiid I, kohvhappeglükosiid, O-kafeoüüldigalloüül-beta-D-glükosiid V ja 1-O-kafeoüül-3-O-galloüül-4,6-HHDP-beta-D-glükosiid.
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DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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