Absolute Configuration of Falcarinol (9Z-heptadeca-1,9-diene-4,6- diyn-3-ol) from Pastinaca sativa

Falcarinol (9Z-heptadeca-1,9-diene-4,6-diyn-3-ol; 1) is a polyacetylene commonly found in several plant families. The absolute configuration of naturally occurring 1 is not clear and contradictory results have been reported in the literature. Determination of the absolute configuration of 1 from Pastinaca sativa L. was carried out. Isolation of 95% pure 1 was performed via successive fractionation and preparative-HPLC. A racemic mixture comprised of 3R-1 and 3S-1 was synthesized in order to confirm the absolute configuration of the isolated natural product using chiral HPLC. Based on a combination of chiral HPLC and specific rotation, 1 present in P. sativa was found to have a 3R absolute configuration (i.e. (3R, 9Z)-heptadeca-1,9-diene-4,6-diyn-3-ol)

Liquid chromatography-tandem mass spectrometry - Application in the clinical laboratory

This review provides a concise survey of liquid chromatography tandem mass spectrometry (LCTMS) as an emerging technology in clinical chemistry. The combination of two mass spectrometers with an interposed collision cell characterizes LCTMS as an analytical technology on its own and not just as a more specific detector for HPLC compared with conventional techniques. In LCTMS, liquid chromatography is rather used for sample preparation but not for complete resolution of compounds of interest. The instrument technology of LCTMS is complex and comparatively expensive; however, in routine use, methods are far more rugged compared to conventional chromatographic techniques and enable highthroughput analyses with very limited manual handling steps. Moreover, compared to both gas chromatographymass spectrometry (GCMS) and conventional HPLC techniques, LCTMS is substantially more versatile with respect to the spectrum of analyzable compounds. For these reasons it is likely that LCTMS will gain far more widespread use in the clinical laboratory than HPLC and GCMS ever did. In this article, the key features of LCTMS are described, method development is explained, typical fields of application are discussed, and personal experiences are related

Capillary HPLC Separation of Selected Neuropeptides

Neuropeptides play a pivotal role in brain and peripheral nervous system function. As high performance liquid chromatography (HPLC) becomes the central tool in the separation and characterization of peptide and protein samples, its selectivity optimization has attracted increasing attention. This research program aims to develop useful, quantitative analysis methods for neuropeptides and their hydrolysis fragments by capillary HPLC. Related peptide pairs are successfully separated, such as leu-enkephalin and [Des-Tyr1] leu-enkephalin, dynorphin A and dynorphin B, galanin and its fragment Gal1-16. The hydrolysis of leu-enkephalin to [Des-Tyr1] leu-enkephalin by organotypic hippocampal slice cultures (OHSCs) can be monitored by the same HPLC system. The separation of seven hippocampal neuropeptides with similar hydrophobicity, Bj-PRO-5a, [Des-Tyr1] leu-enkephalin, leu-enkephalin, pentagastrin, Antho-RW-amide I, dynorphin A 1-6 and angiotensin II, is accomplished by thermally tuned tandem capillary columns (T3C). The chromatographic selectivity is continuously, systematically and significantly optimized by individual adjustment of each column’s temperature. The T3C concept is applied for the first time with capillary columns, which is an important step towards optimization of selectivity for separations of small samples by liquid chromatography

AntiMtb activity of triterpenoid-rich fractions from Spondias mombin L.

Spondias mombin L. used in traditional medicine because of its antimicrobial properties was found to contain cardiac glycosides, flavonoids, tannins, and anthraquinones in the stem bark. Bioassay-directed fractionation of the methanol extract of Spondias mombin was carried out with VLC and HPLC. Isolates were evaluated for antimtb activity which led to the isolation of a series of potential molecules. A semi pure triterpenoid that demonstrated potency of 92.8% inhibition against Mycobaterium tuberculosis (Mtb) at a concentration of 64μg/ml was further purified by HPLC. Keywords: Spondias mombin; Mycobaterium tuberculosis; Triterpenoid

Journal Staff

I detta projektarbete skulle tre olika ölsorters beska bestämmas. Beskan skulle bestämmas analytiskt genom två metoder, en HPCL och en spektrofotometrisk. Det skulle även avgöras vilken av metoderna som lämpade sig bäst för detta. Ölsorter är ur Lundabryggeriets sortiment.  Beska mäts i IBU som är en förkortning på ”international bitterness units” och är milligram iso-α–syror per liter öl. Den analytiska IBU bestämningen skulle göras för att kunna få en uppskattning om hur riktiga de IBU värden var som Lundabryggeriet tidigare beräknat fram med hjälp ut av ett program, Glenn Tinseths.    De två olika analysmetoderna som användes var, en spektrofotometrisk metod ”Hope bitterness in beer” och en HPLC metod ” Iso α-, α-and β-acid in hope and isomerized hop extracts in beer”.   Under arbetets gång fastställdes det att tillredningen av extraktionslösningarna i den spektrofotometriska metoden är väldigt beroende på hur länge dessa lösningar skakas. Det fastställdes också att desto mörkare ölet var desto viktigare blev skakningstiden.    För HPLC metoden fastställdes det att lösligheten av substansen ICE-I3, i standarden, beror på polariteten i lösningsmedlet och att det inte är optimalt att använda svagt försurad metanol, som var angivet i metoden ”Iso α-, α-and β-acid in hope and isomerized hop extracts in beer”. Då metanolen är svagt försurad är den även mer polär, vilket resulterade i att ICE-I3 inte kunde lösas. Att använda metanol som inte var försurad visade sig vara mycket mer lämpligt.    I detta fall kunde det konstateras att den spektrofotometriska metoden var mer osäker än HPLC, speciellt då skakningstiden för fullständig extraktion av de isomerade syrorna inte kunde fastställas. Därför anses det vara bättre lämpat att fokusera på HPLC metoden vid fortsatt arbete för att fastställa ölsorternas IBU.In this project, the bitterness of three different kinds of beers was to be determined. The bitterness would analytically be determined with two methods, a HPLC method and a spectrophotometric method. The aim of the project was also to decide whitch of the methods that was best suited for this determination.   Bitterness is measured in IBU which is an abbreviation of “International Bitterness Units” and is measured in milligram iso-α-acids per liter of beer. The analytical determination of the IBU was to be made, in order to get an estimate of how accurate previous entered IBU values were. Those values were estimated using calculations in the program, Glenn Tinseths.    The determination of the IBU was executed with two different methods of analysis, a spectrophotometric method “Hope bitterness in beer” and a HPLC method “Iso α-, α- and β-acid in Hope and isomerized hop extracts in beer”.    During the work it was concluded that the preparation of the extraction in the spectrophotometric method is very dependent on how long the solvents are shaken. It was also concluded that, the darker the beer was the more important the time of shaking the solvents was.    For the HPLC method, it was determined that the solubility of substance ICE I3, in the standard, depends on the polarity of the solvent and that it is not optimal to use low acidified methanol, which was specified by the method “Iso α-, α-and β-acid in Hope and isomerized hop extracts in beer”. When methanol is weakly acidfied, it is also more polar, resulting in that the ICE-I3 could not be resolved. Using methanol that was not acidified at all was shown to be more appropriate.    Finally, it was determined that the spectrophotometric method was more uncertain than the HPLC, especially when the specific time of shaking the solvents for complete extraction of the isomerade acids, could not be determined. The HPLC method is therefore considered to be the better fit of the two, and should be focus in further work of determining the beers IBU

Allelopathic effect of the Cladonia verticillaris lichen extracts and fumarprotocetraric acid on the early growth of germinated seedlings in Allium cepa L.

The allelopathic activity of the different type of Cladonia verticillaris lichen extracts and fumarprotocetraric acid on the early growth of A. cepa (IPA 6) germinated seedlings depends on their chemical composition and concentration, respectively. It was observed that the length of the radicle was significantly stimulated by fumarprotocetraric acid at high concentrations and by the total extract of C. verticillaris thalli, which contained high level of fumarprotocetraric, acid confirmed by HPLC – technique. In addition, it was found, that the phosphate buffer extract, which contained high level of methy betha-orcinol carboxilate measured by HPLC, significantly reduced the length of the hypocotyls. Under our experimental conditions there was no influence of different type of extract and fumarprotocetraric acid on the seed germination ratio of A. cepa, in relation to control. From the study of HPLC it was found that fumarprotocetraric acid and methy betha-orcinol carboxilate were present in all extracts at different concentrations, according to the method of extraction

Developing an Analytical Method for Separating and Quantifying RNA Generated in In Vitro Transcription Reactions

The generation of run-off transcripts from in vitro transcription reactions is a useful technique in the study of transcription regulation. There are currently limited ways in which these run-off transcripts can be analyzed, and few that are truly quantitative. Our aim is to establish a method using ion-pair reverse phase high performance liquid chromatography (IP RP HPLC) to analyze RNA transcripts from in vitro transcription reactions. We were able to demonstrate that we could recapitulate the separation of DNA based on size using our IP RP HPLC method. The application of this method was also able to effectively separate RNA based on size in the size range of 281 – 1908 bp. Using a simple in vitro transcription system with T7 RNA polymerase and a linear DNA template with a single promoter, we showed detection of the RNA run-off transcript in the size range demonstrated. We would like to apply this method to more complex in vitro transcription systems and demonstrate the ability to quantify RNA using IP RP HPLC

Separation of Nucleic Acids by Ion Pair Reversed Phase High Performance Liquid Chromatography (IP RP HPLC)

Ion-pair reversed-phase high performance liquid chromatography (IP RP HPLC) is shown to be an effective method to reliably analyze DNA. IP RP HPLC is a much faster and safer alternative to conventional methods of DNA separation and quantification. The method described here utilized a two-buffer effluent system consisting of triethylammonium acetate (TEAA) and acetonitrile (ACN). The method reliably separated and quantified DNA samples of 54 and 58 nt. This method will be used and optimized to separate similarly sized RNA samples. The ultimate goal is to separate mixtures of nucleotides generated from in-vitro transcription reactions