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Atmospheric pressure ionization time-of-flight mass spectrometry coupled with high-performance liquid chromatography was used to characterize the in vitro metabolites of glyburide. Metabolic products formed in vitro by human microsomes were separated using a C18 column with gradient elution at a flow rate of 200 microL/min without postcolumn splitting. In-source collision-induced dissociation (CID) by automated nozzle potential switching was employed to obtain both abundant protonated molecules and characteristic fragments whose accurate masses were measured simultaneously by internal mass calibration, performed by continuous postcolumn infusion of two reference standards. The mass errors were within 9 ppm for all ions measured, whose abundance was greater than 5%, relative to the most abundant isotopic "A" ion. Exact mass differences between the parent drug and metabolite(s) were determined and these values corresponded to a unique elemental composition. The elemental compositions of all metabolite fragment ions were generated based upon the known compositional elements of the protonated molecule. The structures of metabolites and their fragment ions were proposed based on the determined elemental composition and in-source CID spectra. The elemental composition and fragmentation pathways of four cyclohexyl hydroxylation metabolites and one ethylhydroxy metabolite are discussed.

Background: To ensure that PK data generated from DBS samples are of the highest quality, it is important that the paper substrate is uniform and does not unduly contribute to variability. This study investigated any within and between lot variations for four cellulose paper types: Whatman™ FTA®DMPK-A, -B and -C, and 903®(GE Healthcare, Buckinghamshire, UK). The substrates were tested to demonstrate manufacturing reproducibility (thickness, weight, chemical coating concentration) and its effect on the size of the DBS produced, and the quantitative data derived from the bioanalysis of human DBS samples containing six compounds of varying physicochemical properties. Results & discussion: Within and between lot variations in paper thickness, mass and chemical coating concentration were within acceptable manufacturing limits. No variation in the spot size or bioanalytical data was observed. Conclusion: Bioanalytical results obtained for DBS samples containing a number of analytes spanning a range of chemical space are not affected by the lot used or by the location within a lot.

Background: For shipping and storage, dried blood spot (DBS) samples must be sufficiently dry to protect the integrity of the sample. When the blood is spotted the humidity has the potential to affect the size of the spot created and the speed at which it dries. Results: The area of DBS produced on three types of substrates were not affected by the humidity under which they were generated. DBS samples reached a steady moisture content 150 min after spotting and 90 min for humidities less than 60% relative humidity. All packaging materials examined provided some degree of protection from external extreme conditions. However, none of the packaging examined provided a total moisture barrier to extreme environmental conditions. Conclusion: Humidity was shown not to affect the spot area and DBS samples were ready for shipping and storage 2 h after spotting. The packing solutions examined all provided good protection from external high humidity conditions.

Background: A novel device and procedure for the collection and isolation of microvolumes of plasma have been developed and two pilot rodent PK studies have been completed. Results: This method involves collection of blood into a plastic-wrapped, EDTA-coated capillary tube, containing a small amount of a thixotropic gel and a porous plug. Following blood collection, the capillary is placed into a secondary labeled container suitable for centrifugation and plasma is generated. During centrifugation, the thixotropic gel isolates the plasma from the red blood cells and creates a physical barrier between the two matrices. The plasma is then dispensed from the capillary tube into a separate container for storage or processing. Conclusion: A simple and robust novel approach for the collection of small plasma volumes from rodent TK studies has been demonstrated.

Background: At the start of their work, the European Bioanalysis Forum dried blood spots microsampling consortium did not form a dedicated team to investigate the spot homogeneity. However, two teams performed experiments that produced results relating to sample homogeneity. Results: The data, which were produced via two different approaches (a radiolabeled and a nonradiolabeled approach), are highly complementary and demonstrate clear effects on sample inhomogeneity due to the substrate type, compound and hematocrit levels. Conclusion: The results demonstrate that sample inhomogeneity is a significant hurdle to the use of dried blood spots for regulated bioanalysis that should be investigated further in the method establishment phase if the whole spot is not sampled. © 2013 Future Science Ltd.

The transformations undergone by chlorophyll a under anoxic conditions have been simulated by using the widespread marine prymnesiophyte Emiliania huxleyi as a substrate for a mixed bacterial community by incubation in a sediment slurry under sulphate reducing conditions. This resulted in the formation of pyrophaeophytin a after 77 days, along with smaller amounts of phaeophorbide a, pyrophaeophorbide a and mesopyrophaeophorbide a, from an original pigment distribution comprising mainly phaeophytin a, with a lower abundance of chlorophyll a. Mesopyrophaeophorbide a has not been reported previously as a product of any chlorophyll a defunctionalization study. Its formation under the conditions used suggests that the reduction of the C-3 vinyl substituent, required for transformation of chlorophyll a to a number of sedimentary porphyrins and chlorins, is a process which involves anaerobic bacterial communities.

Dried blood spots (DBS) alongside micro-analytical techniques are a potential solution to the challenges of performing pharmacokinetic (PK) studies in children. However, DBS methods have received little formal evaluation in clinical settings relevant to children. The aim of the present study was to determine a PK model for caffeine using a 'DBS/microvolume platform' in preterm infants.DBS samples were collected prospectively from premature babies receiving caffeine for treatment of apnoea of prematurity. A non-linear mixed effects approach was used to develop a population PK model from measured DBS caffeine concentrations. Caffeine PK parameter estimates based on DBS data were then compared with plasma estimates for agreement.Three hundred and thirty-eight DBS cards for caffeine measurement were collected from 67 preterm infants (birth weight 0.6-2.11 kg). 88% of cards obtained were of acceptable quality and no child had more than 10 DBS samples or more than 0.5 ml of blood taken over the study period. There was good agreement between PK parameters estimated using caffeine concentrations from DBS samples (CL = 7.3 ml h⁻¹ kg⁻¹; V = 593 ml kg⁻¹; t(½) = 57 h) and historical caffeine PK parameter estimates based on plasma samples (CL = 4.9-7.9 ml h⁻¹ kg⁻¹; V = 640-970 ml kg⁻¹; t(½) = 101-144 h). We also found that changes in blood haematocrit may significantly confound estimates of caffeine PK parameters based on DBS data.This study demonstrates that DBS methods can be applied to PK studies in a vulnerable population group and are a practical alternative to wet matrix sampling techniques.

Isotope ratio monitoring GC-MS (irm-GCMS) analyses of individual hydrocarbons isolated from the surface sediment of a small eutrophic lake (Priest Pot, U.K.) and a phytoplankton tow sample from the upper water column have been undertaken in order to assign sources of sedimentary lipids. The δ 13C values for the sedimentary n-alkanes showed no clear distinction between lower molecular weight components (C17–C19) of presumed algal origin and higher members (C23–C33) of presumed higher plant origin, thus indicating a limitation to the use of compound specific isotope analysis in the freshwater system studied. In contrast, the δ 13C values of sedimentary hopenes were markedly depleted (by over 20%) compared with those in the phytoplankton sample from the upper water column. Hop-22(29)-ene in the surficial sediment had a δ 13C value of −55.2%, which contrasts witht he value of the phytoplankton component (−32.7%), attributed to cyanobacteria. These values indicate that a highly 13C-depleted source provides a major contribution to the sedimentary component. It is proposed that the sedimentary hopenes originate in part from methanotrophic bacteria, demonstrating the presence of a bacterial methane cycle in this environment.

To obtain further information about the origin of sedimentary tetrapyrroles such as the alkyl porphyrin desoxophylloerythroaetioporphyrin, the defunctionalization of chlorophyll a has been studied in batch cultures of the marine diatom Phaeodactylum tricornutum, which were induced to undergo senescence by the exclusion of light. Identification of pigments by combined reversed phase high-performance liquid chromatography-mass spectrometry (LC-MS), with on-line photo-diode array detection, revealed conversion of chlorophyll a to phaeophytin a and pyrophaeophorbide a. The results demonstrate that certain chlorophyll a transformation products which occur commonly in aquatic sediments can be formed in part by the action of algal enzymes in the water column. The study provides the first unambiguous identification of pyrophaeophorbide a during senescence of a non-mutant alga.

There are a number of key characteristics of Ukrainian agriculture which are central to the discussion of the reform process. These include the predominance of state ownership and control, lack of commercial management skills, uneven commitment to reform in a decentralized system of responsibility, monopoly, a low level of technology and limited access to resources that facilitate efficient operation of the market. Necessary restructuring will involve three categories of measures including the establishment of a competitive environment, augmenting enterprise response, and macroeconomic stabilization. At present reform has proceeded extremely slowly and speeding the process appears to require Western aid, both financial and technical, to provide a demonstration of the benefits of reform in order to stimulate its more rapid uptake.

A novel technique is presented that addresses the issue of how to apply internal standard (IS) to dried matrix spot (DMS) samples that allows the IS to integrate with the sample prior to extraction. The TouchSpray, a piezo electric spray system, from The Technology Partnership (TTP), was used to apply methanol containing IS to dried blood spot (DBS) samples. It is demonstrated that this method of IS application has the potential to work in practice, for use in quantitative determination of circulating exposures of pharmaceuticals in toxicokinetic and pharmacokinetic studies. Three different methods of IS application were compared: addition of IS to control blood prior to DBS sample preparation (control 1), incorporation into extraction solvent (control 2), and the novel use of TouchSpray technology (test). It is demonstrated that there was no significant difference in accuracy and precision data using these three techniques obtained using both manual extraction and direct elution.

A method is presented for the direct quantitative analysis of therapeutic drugs from dried blood spot samples by mass spectrometry. The method, paper spray mass spectrometry, generates gas phase ions directly from the blood card paper used to store dried blood samples without the need for complex sample preparation and separation; the entire time for preparation and analysis of blood samples is around 30 s. Limits of detection were investigated for a chemically diverse set of some 15 therapeutic drugs; hydrophobic and weakly basic drugs, such as sunitinib, citalopram, and verapamil, were found to be routinely detectable at approximately 1 ng/mL. Samples were prepared by addition of the drug to whole blood. Drug concentrations were measured quantitatively over several orders of magnitude, with accuracies within 10% of the expected value and relative standard deviation (RSD) of around 10% by prespotting an internal standard solution onto the paper prior to application of the blood sample. We have demonstrated that paper spray mass spectrometry can be used to quantitatively measure drug concentrations over the entire therapeutic range for a wide variety of drugs. The high quality analytical data obtained indicate that the technique may be a viable option for therapeutic drug monitoring.

Determining circulating drug concentrations in children is an ongoing obstacle to the development of age-appropriate dosing regimens. The requirement for small blood sample volumes in children compared with adults is a significant barrier to obtaining age-specific pharmacokinetic–pharmacodynamic data for this population and hence optimizing the efficacy and safety profile of medicines used by this group. This article discusses the potential for dried blood spot sampling to offer a solution to this issue.

Dried bloodspot (DBS) technology has been available for many decades but only in the last five years has it been considered for routine bioanalysis of blood samples collected on preclinical and clinical studies as part of a drug development programme. Advantages of using DBS versus typical plasma samples include smaller blood volumes, less processing of the samples (e.g. no centrifugation) and no requirement for storing or shipping of the samples at frozen temperatures. The current study compared blood concentrations (AUC0− t and Cmax) from rats given an oral dose of acetaminophen (APAP) using two different sampling sites (caudal venepuncture versus tail snip), two different collection methods (3 separate 15 μL ethylenediaminetetraacetic acid [EDTA]-coated capillary tubes versus an EDTA integrated capillary blood collection system) and variability between blood spots on one card. There were no noteworthy differences (i.e. two-fold or greater) in blood concentrations of APAP using the different sites or methods. Furthermore, comparisons of the APAP blood concentrations in the original spot to a duplicate bloodspot from the same bloodspot card were within 12% of the original concentration.

The use of dried blood and dried plasma spots for storage and transportation of samples derived from clinical trials holds the promise to reduce cost, simplify storage and shipping as well as reducing animal usage. From the bioanalysts’ point of view, these dried-paper samples add an extra layer of complexity to the analysis introducing extra matrix effects from the paper itself and sometimes from antiviral treatments applied to the card. In this article we demonstrate the use of the sub-2-µm particle LC–MS/MS for the bioanalysis of samples derived from a dried blood spot. The higher resolution provided by these small-particle separations allowed for greater resolution of the analyte from the endogenous components in blood samples and from the card-treatment chemicals. The method -development process was enhanced by the use of MS, which could simultaneously acquire full scan and multiple reaction monitoring data, allowing resolution from metabolites and endogenous matrix components. The use of this approach produced sensitivity levels in the 50–100 pg/ml range and analysis times in the 1–2 min range, which was five-times more sensitive and three-times faster than HPLC. This throughput and sensitivity makes this approach ideal for the analysis of preclinical and clinical studies derived from dried blood spots.

Background: As hematocrit levels are known to vary between individuals and with disease state, its effect on the physical characteristics of dried blood spot (DBS) samples and on the accurate quantification of analytes within these samples is examined. Results: The area of DBS samples decreases with increasing hematocrit levels in a linear manner on the three cellulose paper substrates tested. Furthermore, a bias was observed in the concentrations of two analytes determined in DBS samples at different hematocrits, which in some cases exceeded acceptable values, particularly for hematocrits outside normal values. Conclusion: If it is expected that the hematocrit of study samples will vary from values considered normal, then its effect on the quantitative determination of an analyte in DBS samples should be investigated as part of the method development and validation. If an unacceptable effect is observed, then this will need to be addressed, by modification of the analytical method, or the inclusion of quality control samples at different hematocrit levels to show control of the assay.

ISSN 1757-6180 10.4155/BIO.10.153 © 2010 Future Science Ltd Bioanalysis (2010) 2(11), 1781 Well here we are again! Following hot on the heels of the special focus issue of Bioana lysis dedicated to dried blood spots in August 2010, we have another special issue concentrating on the same subject. The large volume of highquality contributions in these two editions and the numerous dedicated conference sessions and workshops on this subject in the last 2 years is rapidly contributing to a broader understanding and acceptance of this technique by the drug bioana lysis community. However, the work of this community is increasingly highly regulated, which naturally leads to a conservative approach and in-depth questioning of any new technologies. This is resulting in a number of members of the community holding back on implementing any real change, whilst they wait for others to trip up, or for the regulators to make a proclamation etched in stone about the suitability of the technique. Whilst this may at times be ‘irritating’ to the leaders who just want to get out there and do it – “isn’t it obvious?” – this is an understandable reaction that must be heard. We need to take the time to thoroughly understand the technique and to perform the best science possible. However, it is my belief that we should not let all the understandable questions and reservations bury the pure fact that there are real benefits to be had with this technique. Standing still is not an option. The pressure from society to deliver ethical and environmentally friendly solutions is ever present. Added to this is the need of the pharmaceutical industry and healthcare providers to get better value for their money. Dried blood spot sampling delivers on all these aspects in spades and so will become an accepted part of the drug-development landscape of the future. The revolution is here! Anyway, enough of my rant! I welcome you to this special focus issue of Bioana lysis dedicated to dried blood spot sampling. I would like to thank the authors for sharing with us their high-quality science and discussion. I would also like to thank the dedicated and hard work of the editorial staff for putting together this special issue.

A novel approach has been developed for the quantitative determination of circulating drug concentrations in clinical studies using dried blood spots (DBS) on paper, rather than conventional plasma samples. A quantitative bioanalytical HPLC-MS/MS assay requiring small blood volumes (15 microL) has been validated using acetaminophen as a tool compound (range 25 to 5000 ng/mL human blood). The assay employed simple solvent extraction of a punch taken from the DBS sample, followed by reversed phase HPLC separation, combined with selected reaction monitoring mass spectrometric detection. In addition to performing routine experiments to establish the validity of the assay to internationally accepted criteria (precision, accuracy, linearity, sensitivity, selectivity), a number of experiments were performed to specifically demonstrate the quality of the quantitative data generated using this novel sample format, namely, stability of the analyte and metabolites in whole human blood and in DBS samples; effect of the volume of blood spotted, the device used to spot the blood, or the temperature of blood spotted. The validated DBS approach was successfully applied to a clinical study (single oral dose of 500 mg or 1 g acetaminophen).

In addition to free sterols, higher plants contain significant amounts of sterol in the form of steryl fatty acyl esters, steryl ferulates, steryl glycosides, and steryl acylglycosides. Methods have now been developed for the analysis of these various steryl conjugates employing high temperature capillary gas chromatography and mass spectrometry.

Exposure of female Nucella lapillus to tributyltin (TBT) in seawater at a concentration of 40 ng Sn/litre led to accumulation of TBT in the tissues, and an increase in penis length compared to control animals. Investigation of the steroid concentrations by radioimmunoassay revealed a significant increase in testosterone after 28 days exposure to TBT. No significant effect was noted upon the amounts of progesterone or estradiol-17β. When testosterone was injected into female N. lapillus in the absence of TBT, penis length was found to increase significantly. These observation suggest that there may be an association between the change in testosterone titre in response to exposure to TBT and the development of imposex in the dogwhelk.

This paper explores the linkages between structural adjustment and the liberalization of agricultural marketing in sub‐Saharan Africa (SSA). It examines the nature of structural problems, which have been manifested in stagnating output and balance of payments difficulties. Policy responses are described, in terms of short term macroeconomic stabilization and longer term growth‐oriented adjustment policies. The process of structural adjustment in Africa is surveyed, and policies and stages in the liberalization of markets are considered. Debates on agricultural marketing in SSA are reviewed. This leads into an analysis of the specific issues which arise while marketing policy reform proceeds as an integral part of structural adjustment strategies.

A reversed phase HPLC-MS/MS method has been developed and validated for the quantitative bioanalysis of acetaminophen in dried blood spots (DBS) prepared from small volumes (15 μL) of dog blood. Samples were extracted for analysis with methanol. Detection was by positive ion TurboIonSpray™ ionisation combined with selected reaction monitoring MS. The analytical concentration range was 0.1–50 μg/mL. The intra-day precision and bias values were both less than 15%. Acetaminophen was stable in DBS stored at room temperature for at least 10 days. The methodology was applied in a toxicokinetic (TK) study where the data obtained from DBS samples was physiologically comparable with results from duplicate blood samples (diluted 1:1 (v/v) with water) analysed using identical HPLC-MS/MS conditions. This work demonstrates that quantitative analysis of a drug extracted from DBS can provide high quality TK data while minimising the volume of blood withdrawn from experimental animals, to an order of magnitude lower than is current practice in the pharmaceutical industry. This is the first reported application of DBS analysis to a TK study in support of a safety assessment study. The success of this and similar, related studies has led to the intent to apply DBS technology as the recommended analytical approach for the assessment of pharmacokinetics (PK)/TK for all new oral small molecule drug candidates, which have previously demonstrated a successful bioanalytical validation.

Electrospray ionization mass spectrometry is a valuable tool in the identification and quantification of drug metabolites in biological fluids. However, there are many instances where matrix components present in these fluids interfere with analyte detection and prevent the acquisition of accurate or complete results. In some instances, the matrix can suppress ionization to such an extent that analytes are completely undetectable by MS. In this work, we investigate how ionization and ion-transfer efficiencies are affected by drastically reducing the flow into the MS. A postcolumn concentric flow-splitting device was constructed to allow the measurement of analyte signal and ionization suppression across a range of flow rates (0.1-200 microL/min). Using this device, the effects of flow rate on signal intensity and ionization suppression were measured in analytical experiments that included flow injection analysis MS, postcolumn addition LC-MS, and on-line LC-MS analysis of metabolites generated from rat liver microsomes. The device used to deliver 0.1 microL/min flows is referred to as a nanosplitter because it achieved high split ratios (2000:1), producing flow rates comparable to those observed in nanoelectrospray. The nanosplitter maintained chromatographic integrity with high fidelity and allowed the direct comparison of analyte signal across a range of flow rates (0.1-200 microL/min). A significant improvement in concentration and mass sensitivity as well as a reduction in signal suppression is observed when the performance at 200 versus 0.1 microL/min flow rate is compared. Using this specially designed concentric splitting device, the advantages of ultralow flow ESI were easily exploited for applications employing large bore chromatography.

Delivering Neonatal Drugs Research: Acceptability of Dried Blood Spot Sampling for Pharmacokinetic Research in Premature Infants

Summary This article argues that it is important to differentiate between high value export crops traditionally grown in the estate sector and other crops more often associated with the smallholder sector, in terms of their economic and agricultural characteristics. High value export crops require that a specific set of input services be provided if they are to be successfully grown by smallholders. Typical rural development programmes in Africa have not provided these inputs and have locked smallholders into the production of food crops and lower value export crops which have been historically associated with the smallholder sector, with important consequences for equity and growth. Resume La Banque Mondiale presente‐t‐elle un Handicap pour la Production a l'Exportation dans les Petites Exploitations? Le Cas du Malawi Cet article insiste sur le fait qu'il est important de faire la difference, suivant leurs caracteristiques economiques et agricoles, entre les produits a l'exportation et de valeur elevee, traditionellement cultives dans le secteur des grandes exploitations, et la production associee plus generalement avec les petites exploitations. Les produits agricoles de valeur elevee, destines a l'exportation demandent la mise en oeuvre d'un nombre specifique de services afin d'obtenir des resultats satisfaisants lorsque la production est assuree par de petites exploitations. Les programmes typiques de developpement rural en Afrique n'ont pas offert la garantie de ces investissements et ont limite les petits exploitants a la production de produits agricoles de premiere necessite, traditionellement associes avec le secteur des petites exploitations; ceci a eu des conse quences importances en ce qui concerne l'equite et la croissance. Resumen ?Inhibe el banco mundial los cultivos comerciales? El caso de Malawi Este articulo destaca la importancia de distinguir los cultivos de exportacion de alto valor producidos tradicionalmente en el sector de haciendas de aquellos originados mas frecuentemente en el de pequenas granjas, en terminos de sus caracteristicas agricolas y economicas. Si se pretende que los primeros sean producidos exitosamente por pequenos agricultores, debe proporcionarse a estos el conjunto de servicios especificos requeridos. En Africa, los tipicos programas de desarrollo rural no proporcionaron estos servicios y encerraron a los pequenos agricultores en la produccion de alimentos y de cultivos de exportacion de bajo valor, historicamente asociados al sector de pequenos productores, con serias consecuencias para la equidad y el crecimiento.

Approaches to the isolation and characterisation of intact steryl ferulates were investigated. Alkaline washing of the total lipid extract obtained from seeds allowed preliminary separation of a phenolic ester containing fraction from the abundant neutral lipids (comprising largely triacylglycerides, sterols and steryl fatty acyl esters). Subsequent thin-layer chromatography (silica gel) afforded purified steryl ferulates. Separation of individual molecular species was achieved by reversed-phase (ODS) high-performace liquid chromatography (HPLC) using the acetate derivatives of the steryl ferulates, or by high-temperature gas chromatography (GC) of the underivatised steryl ferulates or their acetates or trimethylsilyl ethers. Characterisation of intact individual molecular species was based on the electron impact mass spectra obtained by GC—mass spectrometry (MS) of the underivatised ferulates or their trimethylsilyl ethers, or by direct insertion probe MS of the acetates of the steryl ferulates obtained by preparative HPLC. The feasibility of the above approach was established using the well characterised steryl ferulate mixture γ-oryzanol obtained from rice bran oil. The methods were subsequently applied to the analysis of the steryl ferulates present in seeds of maize ( Zea mays ).

Toxicokinetic analysis is an essential part of nonclinical drug development. Advances in bioanalytical techniques have opened up the potential to use smaller sample volumes (microsamples) to assess drug exposure in blood, plasma and/or serum. Microsampling can increase the amount of nonclinical safety information available, improve its validity by linking toxic effects to drug exposure in individual animals and represents the most significant opportunity to reduce animal use in toxicology studies in the short term. In May 2013, a workshop was held with 80 delegates from 33 companies with the aim of sharing information and knowledge on microsampling technologies. This article covers the discussions at the workshop, current practice in the industry, regulatory experiences and the future direction of microsampling across drug development.

Synthesis of steryl palmitates, varied in the nature of the steryl moiety, provided model compounds for investigation of the mass spectrometric behavior of steryl long-chain fatty acyl esters. The structure of the steryl moiety was varied according to: (i) position and degree of unsaturation in the steroid nucleus and C-17 side-chain, (ii) position and degree of methylation, (iii) presence or absence of a 9 beta, 19-cyclopropane ring. Compounds were chosen so as to be representative of biochemically important steryl esters. Electron impact (EI) behavior of steryl palmitate esters closely resembles that of their short-chain (e.g. acetate) counterparts. M+.ions were generally weak or absent and the major high mass ions arose from characteristic fragmentations of the steroid nucleus following loss of the acyl moiety ([M-RCO2H]+.). Fragment ions characteristic of the acyl moiety were lacking. Negative ion chemical ionization (NICI) using ammonia as reagent gas, on the other hand, afforded spectra containing characteristic fragment ions [RCO2]-, [RCO2-18]-, and [RCO2-19]- from which the nature of the fatty acyl moiety can be readily deduced. Hence, NICI and EI provide complementary means of ionization for the mass spectrometric determination of structures of steryl esters.

Ultra-performance liquid chromatography (UPLC) combined with mass spectrometric detection (MS) is used successfully in the bioanalysis of small molecule drug candidates in plasma. UPLC-MS is shown to increase sample throughput by reducing run times over 3-fold, without compromising analytical sensitivity or analyte resolution. The technique is demonstrated to be practical and robust on a commercially available ultra-high pressure system when injecting extracts of plasma and has also shown to be a technique that can be used effectively on a conventional high-performance liquid chromatography system fitted with short columns (

This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in Dark Matter" held at University of Maryland on March 23-25, 2017., Comment: 102 pages + references

In order to obtain further information about the origin of sedimentary tetrapyrroles we have studied the defunctionalisation of algal chlorophyll a in the laboratory, and monitored changes in pigment composition by LC-MS. Cells of the diatom Phaedactylum tricornutum were lysed and incubated in the dark. This resulted in the formation of high relative abundances of chlorophyllide a and smaller amounts of phaeophytin a, phaeophorbide a and pyrophaeophorbide a within 3 h. This provides further evidence that algal senescence is probably an important process for the formation of such defunctionalised products in environments where zooplankton herbivory does not occur. In addition, the transformation time approximated to zooplankton gut clearance rates, implying that the chlorophyll transformations which have been observed during zooplankton herbivory may result in part from the endogenous enzymes of the ingested alga. Degradation of the marine diatom Thallasiosira weissflogii by a mixed aerobic bacterial community was performed in a system designed to mimic sedimentation of algal cells in the marine environment in the absence of grazing. This led to a decrease in the amounts of chlorophyll a, phaeophytin a and phaeophorbide a, and the appearance of small amounts of pyrophaeophorbide a. The appearance of such defunctionalisation products, also found in senescence-type experiments, suggests that the bacterial community did not play a role in their formation through microbial transformation.