bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of starch and other carbon fractions from higher plant leaves for stable carbon isotope analysis
Authors: Wanek Wolfgang , Heintel Sonja , Richter Andreas 
Published: August 2002

AbstractThe measurement of the carbon isotope composition of starch and cellulose still relies on chemical isolation of these water‐insoluble plant constituents and subsequent elemental analysis by isotope ratio mass spectrometry (EA/IRMS) of the purified fractions, while δ13C values of low‐molecular‐weight organic compounds are now routinely measured by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Here we report a simple and reliable method for processing milligram quantities of dried plant material for the analysis of the carbon isotope composition of lipids, soluble sugars, starch and cellulose from the same sample. We evaluated three different starch preparation methods, namely (1) enzymatic hydrolysis by α‐amylase, (2) solubilization by dimethyl sulfoxide (DMSO) followed by precipitation with ethanol, and (3) partial hydrolysis by HCl followed by precipitation of the resulting dextrins by ethanol. Starch recovery for three commercially available native starches (from potato, rice and wheat) varied from 48 to 81% for the techniques based on precipitation, whereas the enzymatic technique exhibited yields between 99 and 105%. In addition, the DMSO and HCl techniques introduced a significant 13C fractionation of up to 1.9‰, while the carbon isotope composition of native starches analyzed after enzymatic digestion did not show any significant difference from that of untreated samples. The enzymatic starch preparation method was then incorporated into a protocol for determinination of δ13C signatures of lipids, soluble carbohydrates, starch and crude cellulose. The procedure is based on methanol/chloroform/water extraction of dried and ground leaf material. After recovery of the chloroform phase (lipid fraction), the methanol/water phase was deionized by ion exchange (soluble carbohydrate fraction) and the pellet treated with heat‐stable α‐amylase (starch fraction). The remaining insoluble material was subjected to solvolysis by diglyme (cellulose fraction). The method was shown to be applicable to foliar tissues of a variety of different plant species (spruce, erect brome, maize and soybean). Copyright © 2001 John Wiley & Sons, Ltd.
Method development for measuring trace levels of penicillins in aqueous environmental samples
Authors: Bruno Federica , Curini Roberta , Corcia Antonio Di , Nazzari Manuela , Samperi Roberto 
Published: August 2002

AbstractA method based on liquid chromatography/mass spectrometry with an electrospray ion source and a single quadrupole instrument (LC/ES‐MS) has been developed for determining trace levels of eight widely used penicillins in aqueous environmental samples. Analyte extraction was performed from 4 L tap water, 2 L groundwater, 1 L river water, 0.2 L treated sewage and 0.1 L raw sewage, by using a Carbograph 4 cartridge. During removal of the solvent, penicillins were purposely allowed to convert into their penicilloyl methyl esters. This ‘in situ’ derivatization step resulted in a dramatic enhancement of the response of the ES‐MS system for non‐amphoteric penicillins. Analyte recoveries were better than 80% irrespective of the type of aqueous sample, with the exception of amoxicillin (76%) and ampicillin (77%) in tap water. At the level of 50 ng/L of each analyte in ground water, the within‐day precision was in the range 6–10%. Calibration curves were linear for injected amounts up to 800 ng, with R2 in the range 0.9952–0.9995. When injecting large equivalent volumes of the aqueous samples, the electrospray matrix effect altered in‐source collision‐induced dissociation (CID) spectra of the analytes by severely weakening signals for fragment ions, as compared to spectra of reference standards. Remedies to obviate this anomalous unwelcome effect are suggested. On the basis of a signal‐to‐noise ratio of 10, limits of quantification were estimated to range between 2 (cloxacillin) and 24 ng/L (amoxicillin) in river water. Copyright © 2001 John Wiley & Sons, Ltd.
Parallel extraction columns and parallel analytical columns coupled with liquid chromatography/tandem mass spectrometry for on‐line simultaneous quantification of a drug candidate and its six metabolites in dog plasma
Authors: Xia Yuan‐Qing , Hop Cornelis E.C.A. , Liu David Q. , Vincent Stella H. , Chiu Shuet‐Hing L. 
Published: August 2002

AbstractA method with parallel extraction columns and parallel analytical columns (PEC‐PAC) for on‐line high‐flow liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and validated for simultaneous quantification of a drug candidate and its six metabolites in dog plasma. Two on‐line extraction columns were used in parallel for sample extraction and two analytical columns were used in parallel for separation and analysis. The plasma samples, after addition of an internal standard solution, were directly injected onto the PEC‐PAC system for purification and analysis. This method allowed the use of one of the extraction columns for analyte purification while the other was being equilibrated. Similarly, one of the analytical columns was employed to separate the analytes while the other was undergoing equilibration. Therefore, the time needed for re‐conditioning both extraction and analytical columns was not added to the total analysis time, which resulted in a shorter run time and higher throughput. Moreover, the on‐line column extraction LC/MS/MS method made it possible to extract and analyze all seven analytes simultaneously with good precision and accuracy despite their chemical class diversity that included primary, secondary and tertiary amines, an alcohol, an aldehyde and a carboxylic acid. The method was validated with the standard curve ranging from 5.00 to 5000 ng/mL. The intra‐ and inter‐day precision was no more than 8% CV and the assay accuracy was between 95 and 107%. Copyright © 2001 John Wiley & Sons, Ltd.
Different quantitation approaches for xenobiotics in human urine samples by liquid chromatography/electrospray tandem mass spectrometry
Authors: Sancho Juan V. , Pozo Oscar J. , López Francisco J. , Hernández Félix 
Published: August 2002

AbstractThe potential of liquid chromatography combined with tandem mass spectrometry (LC/MS/MS) for the determination of pesticide metabolites in human urine at the sub‐ppb level is explored. Metabolites from two organophosphorous pesticides, 4‐nitrophenol (from parathion and parathion‐methyl) and 3‐methyl‐4‐nitrophenol (from fenitrothion), are taken as model analytes to conduct this study.After direct injection of the urine sample (10 µL), different approaches were evaluated in order to achieve correct quantitation of analytes using an electrospray ionisation (ESI) interface. Thus, the feasibility of using external calibration was checked versus the use of different isotope‐labeled internal standards. The advantages of applying coupled‐column liquid chromatography (LC/LC) as an efficient clean‐up without any type of sample manipulation are also discussed.The combination of LC/LC with ESI‐MS/MS allows the direct analysis of free metabolites in urine, as the automated clean‐up performed by the coupled‐column technique is sufficient for the removal of interferences that suppress the ionisation of analytes in the ESI source. Using this procedure with external calibration, good precision and recoveries, and detection limits below 1 ng/mL are reached with analysis run times of around 8 min. The hyphenated technique LC/LC/ESI‐MS/MS is proved to be a powerful analytical tool, allowing the rapid, sensitive and selective determination of 4‐nitrophenol and 3‐methyl‐4‐nitrophenol in human urine without any sample treatment. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of species‐specific components in the venom of Parabuthus scorpions from southern Africa using matrix‐assisted laser desorption time‐of‐flight mass spectrometry
Authors: Dyason Karin , Brandt Wolf , Prendini Lorenzo , Verdonck Fons , Tytgat Jan , Plessis Johan du , Müller Gerbus , Walt Jurg van der 
Published: August 2002

AbstractThe aim of the present study was to analyze mass spectra of scorpions belonging to the genus Parabuthus (Pocock 1890) by means of matrix‐assisted laser desorption time‐of‐flight mass spectrometry (MALDI‐TOFMS) and to construct a species‐specific venom code for species identification. The venom compositions of sixteen Parabuthus species, occurring in southern Africa, were characterized using representative peaks in the molecular mass range of 6400–8400 Da. This mass range is characteristic for the typical long‐chain neurotoxins influencing sodium channels. Only a few of these peptides have been sequenced up to now. The impetus for development of these species‐specific profiles was the observation of unique, highly reproducible mass spectral peaks within a specific species. An identification label for all the different species could be found using a minimum number of peaks. MALDI‐TOFMS is therefore proposed as a complementary method to morphological and behavioural characteristics for species and ultimately subspecies discrimination. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of paramethoxyamphetamine and other amphetamine‐related designer drugs by liquid chromatography/sonic spray ionization mass spectrometry
Authors: Mortier Kjell A. , Dams Riet , Lambert Willy E. , Letter Els A. De , Calenbergh Serge Van , Leenheer André P. De 
Published: August 2002

AbstractParamethoxyamphetamine (PMA) is an amphetamine‐like designer drug that has emerged recently on the European illicit drug market. This drug has a wicked reputation, as a number of lethal intoxications have occurred. A method using high‐performance liquid chromatography coupled to ion trap based mass spectrometry (LC/MS) is described for the determination of this compound together with 3,4‐methylenedioxymethamphetamine (XTC or MDMA), amphetamine and 3,4‐methylenedioxyamphetamine (MDA) in human matrices. A liquid/liquid extraction (LLE) was applied to whole blood, urine and postmortem tissues. Reversed‐phase liquid chromatography was performed on a narrow‐bore phenyl‐type column at a flow rate of 0.3 mL/min. A switch box allowed disposal of early‐eluting irrelevant material to waste, protecting the mass spectrometer from contamination. The column effluent was directed into an ion trap mass spectrometer by a sonic spray ionization (SSI) interface. The method was validated for all three matrices, proving the applicability of SSI even when dealing with complex biological matrices. The within‐and between‐day precisions were less than 17.5% and accuracy was below 16.2%. Weighted (1/x) quadratic calibration curves were generated ranging from 10 to 1000 ng/mL (blood and urine) or 20 to 2000 ng/g (tissue) and correlation coefficients (r2) always exceeded 0.995. In addition, the mass spectrum of PMA is given together with a proposed fragmentation pattern for the obtained LC/MS spectrum. This information can be useful for future identification of PMA with LC/MS in biological matrices as well as in confiscated powders or tablets. Copyright © 2002 John Wiley & Sons, Ltd.
Mass spectral studies on aryl‐substituted N‐carbamoyl/N‐thiocarbamoyl narcotine and related compounds
Authors: Aggarwal Shefali , Ghosh Narendra N. , Aneja Ritu , Joshi Harish , Chandra Ramesh 
Published: August 2002

AbstractPositive ion mass spectral fragmentation of new N‐carbamoyl/N‐thiocarbamoyl derivatives of narcotine and compounds closely related to it are reported and discussed. The techniques used include electron impact (EI), fast‐atom bombardment (FAB), matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) and electrospray ionization tandem mass spectrometry (ESI‐MS/MS). Prominent peaks in the mass spectra of these compounds appear to involve C‐C bond cleavage β to the amine nitrogen with loss of the 4,5‐dimethoxy(1H)isobenzofuranone moiety from their molecular ions, along with another prominent peak at m/z 382. No molecular ion peaks of these compounds were recorded in EI, whereas intense [M + H]+ ion peaks were observed in FAB and ESI spectra. MALDI also yielded [M + H]+ ion peaks in good agreement with FAB and ESI studies. Copyright © 2002 John Wiley & Sons, Ltd.
Solid‐phase derivatization of tryptic peptides for rapid protein identification by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Keough T. , Lacey M. P. , Youngquist R. S. 
Published: August 2002

AbstractSolid‐phase sulfonation of tryptic peptides adsorbed to C18 µZipTips™ has been carried out to facilitate de novo sequencing with mass spectrometry. Peptides are reacted with the sulfonation reagent while they are still adsorbed to the solid phase. Excess reagent passes through the ZipTip™ to waste. Washing the products before subsequent elution from the mini‐column also affords sample cleanup prior to analysis. Near quantitative N‐terminal sulfonation can be achieved reliably at room temperature in only a few seconds. The method has been applied successfully to model peptides and to solution or in‐gel digests of proteins. Current sequencing limits are about 100 fmol of protein. Multiplexed sample sulfonation reactions have been carried out with a manual 8‐position micropipettor or using centrifugal force to reliably pass reagents and wash solutions over sample‐loaded ZipTips™. With multiplexing, overall preparation times have been reduced to about 1 min per sample. The solid‐phase format facilitates efficient use of precious digest samples by enabling them to be recovered from the matrix‐assisted laser desorption/ionization (MALDI) sample stage after mass fingerprinting, derivatized and re‐analyzed by MALDI postsource decay mass spectrometry. Copyright © 2002 John Wiley & Sons, Ltd.
MS3 using the collision cell of a tandem mass spectrometer system
Authors: Cousins Lisa M. , Thomson Bruce A. 
Published: August 2002

AbstractWe report the feasibility of multistage fragmentation in combination with a fast background subtraction method, yielding the equivalent of MS3. The first quadrupole selects an ion of interest, and the ion is axially accelerated into Q2 to generate fragment ions. Subsequent stages of mass selection and fragmentation are obtained by quadrupolar resonant excitation within the Q2 collision cell. The fragments are analyzed downstream by either a resolving quadrupole or a time‐of‐flight (TOF) mass spectrometer, and multistage spectra are obtained by subtraction (MSn − MSn−1) for n = 3 or 4. We discuss the characterization of this method, including product ion arrival times, fragmentation efficiencies, and ion selectivity. We report accurate TOF mass spectra of background‐subtracted MS3 for protonated molecules reserpine (m/z 609), bosentan (m/z 1552), and taxol (m/z 854). Copyright © 2002 John Wiley & Sons, Ltd.
Influence of the eluent composition on the ionization efficiency for morphine of pneumatically assisted electrospray, atmospheric‐pressure chemical ionization and sonic spray
Authors: Dams Riet , Benijts Tom , Günther Wolfgang , Lambert Willy , Leenheer André De 
Published: August 2002

AbstractA comparative study of three atmospheric‐pressure ionization (API) sources for liquid chromatography/mass spectrometry (LC/MS), namely pneumatically assisted electrospray or ionspray (IS), atmospheric‐pressure chemical ionization (APCI), and sonic spray (SS), with respect to the influence of the eluent composition on the ionization of morphine, is presented. The effect of organic modifiers, volatile acids, and buffer systems (with and without pH adjustment) in the LC mobile phase on the ionization efficiency of each interface is described. We conclude that for all three ion sources, the composition of the liquid phase had a serious impact on the ionization of the target compound. For IS and SS, very similar behavior towards the LC eluent was observed. In both cases, an increase in organic modifier resulted in an increase in ionization, while an increasing amount of volatile acid or buffer caused signal suppression. APCI, on the other hand, proved to respond completely differently towards the changes in the eluent. Again, an increased ionization was observed with an increase in organic modifier content but this time also in the presence of mobile phase additives like acids or buffers. Finally, we concluded that APCI proved to be the preferred ion source for the test compound because of its robust character and its direct applicability in traditional LC analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Passive Treatment Alternatives for Remediating Abandoned‐Mine Drainage
Authors: Berghorn George H. , Hunzeker George R. 
Published: August 2002

AbstractAbandoned‐mine drainage (AMD) is drainage flowing from or caused by surface mining, deep
mining, or coal refuse piles that is typically highly acidic with elevated levels of dissolved metals. AMD
results from the interactions of certain sulfide minerals with oxygen, water, and bacteria. Passive treatment
systems have been used to remediate AMD at numerous sites throughout the United States. The theory behind
passive treatment is to allow naturally occurring chemical, biological, and physical reactions that aid in AMD
treatment to occur in the controlled environment of the system, not in the receiving water body. The advantages
of passive treatment over active treatment include lower operation and maintenance costs, virtually no use of
chemicals, and minimal energy consumption. The disadvantages are that smaller volumes of water are treated than
with active systems, and discharges with high concentrations of dissolved metals and extremes of pH may have to
be treated several times within one system to treat the discharge. AMD passive treatment systems include aerobic
treatment systems and anaerobic treatment systems. It is estimated that it will take 50 years and between
$5 billion and $15 billion to remediate all AMD problems in Pennsylvania. © 2001 John Wiley
& Sons, Inc.
The flood of the century on the River Oder: effects on the 0+ fish community and implications for floodplain restoration
Authors: Bischoff A. , Wolter C. 
Published: August 2002

AbstractIn summer 1997, the flood of the century occurred on the River Oder in the Czech Republic, Poland and Germany. Effects of the summer flood on the 0+ fish community were evaluated at the Lower Oder in the Polish–German National Park. Fish were collected from different mesohabitats before the flood, at rising water levels and after the flood using Point Abundance Sampling by electrofishing. Flooding caused changes in local 0+ fish assemblages and partly affected the physical habitat structure. Two sandbars were formed by breaches in the dike system, replacing the former uniform river embankments. Under post‐flood conditions, diversity was increased in nearly all mesohabitats. ‘Wash‐out’ of 0+ fish was highest in poorly structured mesohabitats. Effects of the summer flood on eurytopic species were the most pronounced. We suggest that the progeny of rheophilic species were affected to a lesser extent by flooding because of their adaptation to variable flow conditions. Furthermore, rheophilic 0+ fish were able to colonize the newly created mesohabitats and, thus, benefited from the increased habitat heterogeneity after the flood. In this context, implications for floodplain restoration are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Exploratory research: citizen participation, local government and sustainable development in Australia
Authors: Cuthill Michael 
Published: August 2002

AbstractExploratory research reported in this paper was undertaken in Adelaide, Australia during 1998/99. The purpose of the research is to explore local development practice as evidenced through the experiences and actions of local citizens, community based groups and local government (Neuman, 1994). Results from this first stage research suggest that sustainability initiatives in Australia might best be implemented through a collaborative approach at the local community level involving local citizens working in partnership with local government. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Rejoinder to Homer and Oliva
Authors: Coyle Geoff 
Published: August 2002

AbstractThis rejoinder clarifies that there is significant agreement between my position and that of Homer and Oliva as elaborated in their response. Where we differ is largely to the extent that quantification offers worthwhile benefit over and above analysis from qualitative analysis (diagrams and discourse) alone. Quantification may indeed offer potential value in many cases, though even here it may not actually represent “value for money”. However, even more concerning is that in other cases the risks associated with attempting to quantify multiple and poorly understood soft relationships are likely to outweigh whatever potential benefit there might be. To support these propositions I add further citations to published work that recount effective qualitative‐only based studies, and I offer a further real‐world example where any attempts to quantify “multiple softness” could have lead to confusion rather than enlightenment. My proposition remains that this is an issue that deserves real research to test the positions of Homer and Oliva, myself, and no doubt others, which are at this stage largely based on personal experiences and anecdotal evidence. Copyright © 2001 John Wiley & Sons, Ltd.
Sample size requirements for estimating intraclass correlations with desired precision
Authors: Bonett Douglas G. 
Published: August 2002

AbstractA method is developed to calculate the approximate number of subjects required to obtain an exact confidence interval of desired width for certain types of intraclass correlations in one‐way and two‐way ANOVA models. The sample size approximation is shown to be very accurate. Copyright © 2002 John Wiley & Sons, Ltd.
Wealth and the effects of founder management among IPO‐stage new ventures
Authors: Certo S. Trevis , Covin Jeffrey G. , Daily Catherine M. , Dalton Dan R. 
Published: August 2002

AbstractIPO underpricing is inherently related to both wealth retention and wealth creation. This paper reviews the relationship between IPO underpricing and wealth, then presents the results of an empirical study of the impact of CEO founder status (i.e., is the CEO also the founder?) on IPO underpricing. Results based on data collected from 368 IPO‐stage new ventures suggest that founder management has a positive impact on IPO underpricing, and that the founder management–underpricing relationship is moderated by (a) the IPO market share of the investment banker employed and (b) the proportion of insiders on the IPO firm's board of directors. Copyright © 2001 John Wiley & Sons, Ltd.