Sensitive Detection and Quantification of Oxygenated Compounds in Complex Samples Using GC-Combustion-MS.

This work introduces a new element-selective gas chromatography detector for the accurate quantification of traces of volatile oxygen-containing compounds in complex samples without the need for specific standards. The key to this approach is the use of oxygen highly enriched in O as the oxidizing gas in a combustion unit (800 °C) that allows us to directly and unambiguously detect the natural oxygen present in the GC-separated compounds through its incorporation into the volatile species formed after their combustion and their subsequent degradation to O in the ion source. The unspecific signal due to the low O abundance in the oxidizing gas could be compensated by measuring the / 12 that comes as well from the CO degradation.

Potential of GC-Combustion-MS as a Powerful and Versatile Nitrogen-Selective Detector in Gas Chromatography.

Here, we show the potential and applicability of the novel GC-combustion-MS approach as a nitrogen-selective GC detector. Operating requirements to achieve reproducible and compound-independent formation of volatile NO species as a selective N-signal during the combustion step are described. Specifically, high temperatures (≥1000 °C) and post-column O flows (0.

Quantitative multiplexed elemental (C, H, N and S) detection in complex mixtures using gas chromatography.

We present a novel and single detection approach that enables sensitive, accurate and compound-independent quantification of N, S and H in the individual compounds present in complex samples. Integration of the whole chromatographic profile gives the total content of the elements. Simultaneous universal detection is also achieved using the C profile.

GC-ICP-MS/MS Instrumental Setup for Total and Speciation Sulfur Analysis in Gasolines using Generic Standards.

Quantitative characterization of sulfur-containing petroleum derivatives is mainly limited by the large number of potential targets present and the matrix effects suffered due to the high-carbon-containing matrices. Herein we describe the instrumental modifications required in a commercial GC-ICP-MS/MS instrument, and their corresponding optimization, for turning it into a compound-independent quantitative technique for both total and speciation sulfur analysis in gasolines. Additionally, carbon-derived matrix effects were made negligible for direct and fast total S analysis, making the use of relatively complex isotope-dilution strategies not necessary anymore.

Isotope Dilution Mass Spectrometry for Highly Precise Determination of Dissolved Inorganic Carbon in Seawater Aiming at Climate Change Studies.

Dissolved inorganic carbon (DIC) is one of the most important parameters to be measured in seawaters for climate change studies. Its quantitative assessment requires analytical methodologies with overall uncertainties around 0.05% RSD for clear evaluation of temporal trends.

Instrumental Setup for Simultaneous Total and Speciation Analysis of Volatile Arsenic Compounds in Gas and Liquefied Gas Samples.

Although analysis of metals and metalloids, such as arsenic, is widely spread in many different fields, their analysis in gas and liquefied gas samples is still a challenge. A new GC-ICP-MS set up has been developed for their simultaneous total and speciation analysis in gas and liquefied gas samples without the need of a preconcentration step. An arsine in nitrogen standard was used for optimization and evaluation of the system.

Comparison of gas chromatography-combustion-mass spectrometry and gas chromatography-flame ionization detector for the determination of fatty acid methyl esters in biodiesel without specific standards.

GC-FID has been effectively used as a universal quantification technique for volatile organic compounds for a long time. In most cases, the use of the ECN allows for quantification by GC-FID without external calibration using only the response of a single internal standard. In this paper we compare the performance characteristics of GC-FID with those of post-column (13)C Isotope Dilution GC-Combustion-MS for the absolute quantification of organic compounds without the need for individual standards.

Detection of transgenerational barium dual-isotope marks in salmon otoliths by means of LA-ICP-MS.

The present study evaluates the use of an individual-specific transgenerational barium dual-isotope procedure and its application to salmon specimens from the Sella River (Asturias, Spain). For such a purpose, the use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in combination with multiple linear regression for the determination of the isotopic mark in the otoliths of the specimens is presented. In this sense, a solution in which two barium-enriched isotopes ((137)Ba and (135)Ba) were mixed at a molar ratio of ca.

Individual-specific transgenerational marking of fish populations based on a barium dual-isotope procedure.

The present study focuses on the development and evaluation of an individual-specific transgenerational marking procedure using two enriched barium isotopes, (135)Ba and (137)Ba, mixed at a given and selectable molar ratio. The method is based on the deconvolution of the isotope patterns found in the sample into four molar contribution factors: natural xenon (Xe nat), natural barium (Ba nat), Ba135, and Ba137. The ratio of molar contributions between Ba137 and Ba135 is constant and independent of the contribution of natural barium in the sample.

Development of a dual-isotope procedure for the tagging and identification of manufactured products: application to explosives.

A novel chemical tagging approach, based on a dual-isotope procedure, is presented. The method has been applied to explosives tagging. The method is based on the addition to the explosive of two enriched isotopes of the same element, which may be already present within it, at a given molar ratio.

Use of the stable isotope (57) Fe to track the efficacy of the foliar application of lignosulfonate/Fe(3+) complexes to correct Fe deficiencies in cucumber plants.

Background: During the last decade, environmental concerns regarding the use of recalcitrant synthetic chelates to overcome iron chlorosis has increased and new ligands such as lignosulfonates (LS) have been evaluated. However, the efficacy of these products is variable. In this work a hardwood (eucalyptus) and softwood (spruce) LS were compared to try to relate their physico-chemical characteristics and their efficacy.

Using a dual-stable isotope tracer method to study the uptake, xylem transport and distribution of Fe and its chelating agent from stereoisomers of an Fe(III)-chelate used as fertilizer in Fe-deficient Strategy I plants.

A dual-stable isotope tracer experiment was carried out with Fe-deficient sugar beet plants grown hydroponically and resupplied with differentially Fe labeled racemic and meso Fe(iii)-chelates of the ethylendiamine di(o-hydroxyphenylacetic) acid (o,oEDDHA). No short-term Fe isotope exchange reactions occurred in the nutrient solution and plants did not discriminate between (54)Fe and (57)Fe. After 3-6 h, stable Fe isotopes, chelating agents and chelates were analyzed in roots, xylem sap and leaves by ICP-MS and HPLC-ESI/TOFMS.

Internal correction of hafnium oxide spectral interferences and mass bias in the determination of platinum in environmental samples using isotope dilution analysis.

A method has been developed for the accurate determination of platinum by isotope dilution analysis, using enriched (194)Pt, in environmental samples containing comparatively high levels of hafnium without any chemical separation. The method is based on the computation of the contribution of hafnium oxide as an independent factor in the observed isotope pattern of platinum in the spiked sample. Under these conditions, the ratio of molar fractions between natural abundance and isotopically enriched platinum was independent of the amount of hafnium present in the sample.

Isotope pattern deconvolution as a tool to study iron metabolism in plants.

Isotope pattern deconvolution is a mathematical technique for isolating distinct isotope signatures from mixtures of natural abundance and enriched tracers. In iron metabolism studies measurement of all four isotopes of the element by high-resolution multicollector or collision cell ICP-MS allows the determination of the tracer/tracee ratio with simultaneous internal mass bias correction and lower uncertainties. This technique was applied here for the first time to study iron uptake by cucumber plants using 57Fe-enriched iron chelates of the o,o and o,p isomers of ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA) and ethylenediamine tetraacetic acid (EDTA).

Evaluation of strontium isotope abundance ratios in combination with multi-elemental analysis as a possible tool to study the geographical origin of ciders.

In order to evaluate alternative analytical methodologies to study the geographical origin of ciders, both multi-elemental analysis and Sr isotope abundance ratios in combination with multivariate statistical analysis were estimated in 67 samples from England, Switzerland, France and two Spanish regions (Asturias and the Basque Country). A methodology for the precise and accurate determination of the (87)Sr/(86)Sr isotope abundance ratio in ciders by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) was developed. Major elements (Na, K, Ca and Mg) were measured by ICP-AES and minor and trace elements (Li, Be, B, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Y, Mo, Cd, Sn, Sb, Cs, Ba, La, Ce, W, Tl, Pb, Bi, Th and U) were measured by ICP-MS using a collision cell instrument operated in multitune mode.

Large volume injection in ion chromatography Separation of rubidium and strontium for on-line inductively coupled plasma mass spectrometry determination of strontium isotope ratios.

Large volume injection, up to 5 mL, was evaluated and optimised for the on-line ion chromatographic separation of Rb and Sr before ICP-MS measurement of Sr isotope ratios. Flat-topped chromatographic peaks, ideally suited for multicollector ICP-MS isotope ratio measurements, could be obtained when the composition of the mobile phase (nitric acid and 18-crown-6 ether) was identical to the matrix of the sample. Under those conditions rubidium eluted at the dead volume of the column while strontium produced a flat-topped transient signal with several minutes of stable plateau.

Platinum, palladium, and rhodium in fresh snow from the Aspe Valley (Pyrenees Mountains, France).

Platinum, palladium, and rhodium have been measured in fresh snow samples from 14 locations within the Aspe Valley (Pyrenees Mountains, France) during two winter seasons, February 2003 and March 2004. Ultraclean procedures were employed for the sampling, sample treatment, and analysis in order to reduce sample contamination. Possible spectral interferences on platinum group element (PGE) analysis by inductively coupled plasma mass spectrometry (ICP-MS) were controlled and corrected.

Scanning laser ablation-ICP-MS tracking of platinum group elements in urban particles.

While it has now been demonstrated that platinum group elements (PGE) are released from automobile catalysts into the environment, less is known about the form in which they are emitted and transported. Here we show that scanning laser ablation-inductively coupled plasma-mass spectrometry (scanning laser ablation-ICP-MS) can identify and track individual particles released from automobile catalysts present in environmental particulates and sediments. Particles with high PGE concentrations were found in the exhaust of gasoline and diesel vehicles equipped with catalytic converters.