Renewable Resources Robert-Jan van Putten,†,‡ Jan C. van der Waal,† Ed de Jong,*,† Carolus B. Rasrendra,‡,⊥ Hero J. Heeres,*,‡ and Johannes G. de Vries* †Avantium Chemicals, Zekeringstraat 29, 1014 BV Amsterdam, the Netherlands ‡Department of Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands DSM Innovative Synthesis BV, P.O. Box 18, 6160 MD Geleen, the Netherlands Department of Chemical Engineering, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia

Hydroxymethylfurfural, A Versatile Platform Chemical Made from Renewable Resources

5-Hydroxymethylfurfural (HMF) as a building block platform: Biological properties, synthesis and synthetic applications

Some Typical Advances in the Synthetic Applications of Allenes

Separation of polar compounds on polar stationary phases with partly aqueous eluents is by no means a new separation mode in LC. The first HPLC applications were published more than 30 years ago, and were for a long time mostly confined to carbohydrate analysis. In the early 1990s new phases started to emerge, and the practice was given a name, hydrophilic interaction chromatography (HILIC). Although the use of this separation mode has been relatively limited, we have seen a sudden increase in popularity over the last few years, promoted by the need to analyze polar compounds in increasingly complex mixtures. Another reason for the increase in popularity is the widespread use of MS coupled to LC. The partly aqueous eluents high in ACN with a limited need of adding salt is almost ideal for ESI. The applications now encompass most categories of polar compounds, charged as well as uncharged, although HILIC is particularly well suited for solutes lacking charge where coulombic interactions cannot be used to mediate retention. The review attempts to summarize the ongoing discussion on the separation mechanism and gives an overview of the stationary phases used and the applications addressed with this separation mode in LC.

Hydrophilic interaction chromatography.

Hydrophilic interaction liquid chromatography (HILIC) provides an alternative approach to effectively separate small polar compounds on polar stationary phases. The purpose of this work was to review the options for the characterization of HILIC stationary phases and their applications for separations of polar compounds in complex matrices. The characteristics of the hydrophilic stationary phase may affect and in some cases limit the choices of mobile phase composition, ion strength or buffer pH value available, since mechanisms other than hydrophilic partitioning could potentially occur. Enhancing our understanding of retention behavior in HILIC increases the scope of possible applications of liquid chromatography. One interesting option may also be to use HILIC in orthogonal and/or two-dimensional separations. Bioapplications of HILIC systems are also presented.

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Hydrophilic interaction liquid chromatography (HILIC)—a powerful separation technique

The present work displays capillary liquid chromatographic column switching methodology tailored for determination of benzo[a]pyrene tetrol isomers in biological matrices using on-line fluorescence and μ-electrospray ionization mass spectrometric detection. A well-established off-line crude solid phase extraction procedure was used in order to make the method compatible with several biological matrices. The solid phase extraction eluates were evaporated to dryness, redissolved in 1.0 ml methanol : water (10 : 90, v/v), loaded onto a 0.32 mm I.D. × 40 mm 5 µm Kromasil C18 pre-column for analyte enrichment and back-flushed elution onto a 0.30 mm I.D. × 150 mm 3.5 µm Kromasil C18 analytical column. The samples were loaded with a flow rate of 50 µl min−1 and the tetrols were separated at a flow rate of 4 µl min−1 with an acetonitrile : 10 mM ammonium acetate gradient from 10 to 90%. A sample loading flow rate up to 50 µl min−1 was allowed. The fluorescence excitation and emission were set to 342 and 385 nm, respectively, while mass spectrometric detection of the benzo[a]pyrene tetrols was obtained by monitoring their [M − H]− molecular ions at m/z 319. The method was validated over the concentration range 0.1–50 ng ml−1 benzo[a]pyrene tetrols in a cell culture medium with 100 µl injection volume, fluorescence detection and the first eluting tetrol isomer as model compound, resulting in a correlation coefficient of 0.993. The within-assay (n
				= 6) and between-assay (n
				= 6) precisions were determined to 2.6–8.6% and 3.8–9.6%, respectively, and the recoveries were determined to 97.9–102.4% within the investigated concentration range. The mass limit of detection (by fluorescence) was 3 pg for all the tetrol isomers, corresponding to a concentration limit of detection of 30 pg ml−1 cell culture medium. The corresponding mass spectrometric mass limits of detection were 4–10 pg, corresponding to concentration limits of detection of 40–100 pg ml−1 cell culture medium.

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Determination of benzo[a]pyrene tetrols by column-switching capillary liquid chromatography with fluorescence and micro-electrospray ionization mass spectrometric detection

/pdf/n-quaternary-compounds-part-xxii-quinoline-derivatives-kmgg917tl7.pdf

N-Quaternary Compounds. Part XXII. Quinoline Derivatives.

High-performance liquid chromatographic separation and ultraviolet detection of prostaglandins, oxidized by pyridinium dichromate

Capillary gas chromatography was performed with mass spectrometric detection using a novel microplasma ion source for operation in an element-selective mode. The ion source was a 350 kHz radio frequency helium plasma, which was sustained inside the 4 cm end of a 0.32 mm i.d. fused silica capillary column, and located inside the high vacuum chamber of the quadrupole mass spectrometer. Due to the low volume of the ion source, a stable low pressure discharge was produced utilizing only the 2.25 mL min−1 of GC carrier gas (helium) for plasma support. Small amounts of oxygen (0.1–0.2% v/v) were added to the plasma gas in order to prevent carbon deposits and to enhance signal-to-noise ratios. Chlorine and bromine were selectively detected at the 5–20 pg s−1 level (S/N = 2), and both produced a response that was linear within 3 orders of magnitude.

Capillary Gas Chromatography Coupled with Microplasma Mass Spectrometry – Improved Ion Source Design Compatible with Bench‐Top Mass Spectrometric Instrumentation

Temperature-programmed packed capillary liquid chromatography with UV detection has been used for the separation of a wide range of polystyrenes. The low thermal mass of the reversed phase packed capillary columns (0.32-mm internal diameter) allowed rapid temperature programming for retention control. By the use of temperature gradients as steep as 40°C·min−1, rapid separations (11 minutes) of polystyrene standards (2000–400000) could be achieved. Furthermore, the oligomers of the polystyrene 1000 standard were resolved using temperature programming. When replacing tetrahydrofurane with acetonitrile as mobile phase component, peak splitting within the oligomer peaks was observed, revealing some information about the tacticity of the polystyrene 1000 sample.

Tyge Greibrokk

Papers

Determination of benzo[a]pyrene tetrols by column-switching capillary liquid chromatography with fluorescence and micro-electrospray ionization mass spectrometric detection

N-Quaternary Compounds. Part XXII. Quinoline Derivatives.

High-performance liquid chromatographic separation and ultraviolet detection of prostaglandins, oxidized by pyridinium dichromate

Capillary Gas Chromatography Coupled with Microplasma Mass Spectrometry – Improved Ion Source Design Compatible with Bench‐Top Mass Spectrometric Instrumentation

Temperature-programmed packed-capillary liquid chromatographic separation of polystyrenes