Analysis of quantization error in high-precision continuous-flow isotope ratio mass spectrometry

Sacks, Gavin L.; Wolyniak, Christopher J.; Brenna, J. Thomas

doi:10.1016/j.chroma.2003.08.022

Cited by 11 publications

(14 citation statements)

References 8 publications

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“…In IRMS, the signal recorded is a voltage that is proportional to the ion current. The total peak area over time, A 44 (using m/z 44), is related to the number of moles of CO

_{2}^{+ bold.}

entering the ion source by the following equation:20 where [CO 2 ] is the number of moles of CO 2 , N a is the Avogadro number, e is the ion charge, E is the absolute sensitivity of the isotope ratio mass spectrometer in molecules per ion, and R is the value of the feedback resistor in the amplifier. Since an isotope ratio mass spectrometer is a mass‐flow‐sensitive detector (in contrast to, e.g., electrospray ionisation mass spectrometer, which behaves like a concentration‐dependent detector), the peak area for the same instrument depends on a number of different parameters such as (i) the nature of the analyte, (ii) the amount of analyte per time, (iii) the efficiency of the membranes to extract the CO 2 from the eluent, (iv) the helium flow rate within the membranes, and (v) the split ratio in the open split interface.…”

Section: Resultsmentioning

confidence: 99%

Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry

Godin

Hau

Fay

et al. 2005

Rapid Comm Mass Spectrometry

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In the field of isotope ratio mass spectrometry, the introduction of an interface allowing the connection of liquid chromatography (LC) and isotope ratio mass spectrometry (IRMS) has opened a range of new perspectives. The LC interface is based on a chemical oxidation, producing CO2 from organic molecules. While first results were obtained from the analysis of low molecular weight compounds, the application of compound-specific isotope analysis by irm-LC/MS to other molecules, in particular biomolecules, is presented here. The influence of the LC flow rate on the CO2 signal and on the observed delta13C values is demonstrated. The limits of quantification for angiotensin III and for leucine were 100 and 38 pmol, respectively, with a standard deviation of the delta13C values better than 0.4 per thousand. Also, accuracy and precision of delta13C values for elemental analyser-IRMS and flow injection analysis-IRMS (FIA-LC/MS) were compared. For compounds with molecular weights ranging from 131 to 66,390 Da, precision was better than 0.3 per thousand, and accuracy varied from 0.1 to 0.7 per thousand. In a second part of the work, a two-dimensional (2D)-LC method for the separation of 15 underivatised amino acids is demonstrated; the precision of delta13C values for several amino acids by irm-LC/MS was better than 0.3 per thousand at natural abundance. For labelled mixtures, the coefficient of variation was between 1% at 0.07 atom % excess (APE) for threonine and alanine, and around 10% at 0.03 APE for valine and phenylalanine. The application of irm-LC/MS to the determination of the isotopic enrichment of 13C-threonine in an extract of rat colon mucosa demonstrated a precision of 0.5 per thousand, or 0.001 atom %.

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“…In IRMS, the signal recorded is a voltage that is proportional to the ion current. The total peak area over time, A 44 (using m/z 44), is related to the number of moles of CO

_{2}^{+ bold.}

Section: Resultsmentioning

confidence: 99%

Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry

Godin

Hau

Fay

et al. 2005

Rapid Comm Mass Spectrometry

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“…This is true for all gas species (Sacks et al . ), but it is even more critical for SO 2 , which requires special care to improve peak symmetry as well as to minimise peak tailing (Yun et al . ).…”

Section: Analytical Techniquesmentioning

confidence: 99%

Measurement of ³⁴S/³²S Ratios of NBS 120c and BCR 32 Phosphorites Using Purge and Trap EA‐IRMS Technology

Fourel

Martineau

Seris

et al. 2014

Geostandard Geoanalytic Res

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Measurements of sulfur stable isotope ratios (34S/32S) have suffered from technical difficulties in analysing low‐S materials reducing their use despite their undeniable scientific interest. The measurement of 34S/32S ratios is a powerful tool for deciphering problems such as determining the sources of environmental pollutants, to detect adulteration, tracking the evolution of the redox state of the oceans and quantifying the role of the bacterial activity in sulfide minerals genesis. We have used a high‐precision method of sulfur isotope determination using a new type of elemental analyser based on ‘purge and trap’ technology. This new technique demonstrates the high quality of 34S/32S measurements for samples with S concentrations lower than 1% m/m. International calibrated references of diverse sulfur‐bearing materials were used to calibrate two low (< 1%) S‐bearing phosphorites used as compositional reference material for future use as isotopic references: BCR 32 and NBS 120c. δ34SCDT values of, respectively, 18.2‰ (1s = 0.3; n = 23) and 18.3‰ (1s = 0.4; n = 20) are proposed for these. Calibration of both phosphorites with international reference materials led to calculation of a mean standard error close to 0.4‰. The demonstration of a capability to reliably measure S isotope ratios in low‐S phosphate minerals or rocks opens up new fields of palaeoenvironmental reconstructions.

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“…Data acquisition was carried out using Isodat 2.0 Software (Thermo Finnigan). For carbon GC‐IRMS, ion chromatograms of three isotopic peaks of CO 2 were collected by three individual ion collectors with different specific sensitivities, i.e., ions at m / z 45 ( 13 C 16 O 16 O) and ( 12 C 16 O 17 O) were recorded with 100‐fold sensitivity relative to m / z 44 and ions at m / z 46 ( 12 C 16 O 18 O) were recorded with 300‐fold sensitivity relative to m / z 44 (27,30). We began each run with three injections of the high purity (99.997%) CO 2 reference gas (Airgas, Great Lakes, Independence, OH), of which the second CO 2 peak, seen in Fig.…”

Section: Methodsmentioning

confidence: 99%

Simultaneous Identification and δ¹³C Classification of Drugs Using GC with Concurrent Single Quadrupole and Isotope Ratio Mass Spectrometers*

Muccio

Jackson

2010

Journal of Forensic Sciences

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In this study, δ¹³C values of six cocaine samples were identified and classified using a single quadrupole mass spectrometer and an isotope ratio mass spectrometry (IRMS) as simultaneous gas chromatography detectors. Our instrument modification is simple to use and is useful (i) when the sample is of limited size or can only be injected once, (ii) to help identify peaks in a complicated IRMS chromatogram, and (iii) to help differentiate very simple systems when impurity profiling is not possible. The EI-MS confirmed the identity of cocaine in each sample. The IRMS data distinguished 12 of the 15 possible pair-wise comparisons at the 95% CL. Three samples could not be differentiated by their δ¹³C ratios for cocaine. ANOVA demonstrated that the measurement variance was consistently larger than the sample variance. As the δ¹³C values clearly show, this technique enables the exclusion of a potential common source even when two samples have otherwise identical chemical and physical properties.

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Analysis of quantization error in high-precision continuous-flow isotope ratio mass spectrometry

Cited by 11 publications

References 8 publications

Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry

Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry

Measurement of ³⁴S/³²S Ratios of NBS 120c and BCR 32 Phosphorites Using Purge and Trap EA‐IRMS Technology

Simultaneous Identification and δ¹³C Classification of Drugs Using GC with Concurrent Single Quadrupole and Isotope Ratio Mass Spectrometers*

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Analysis of quantization error in high-precision continuous-flow isotope ratio mass spectrometry

Cited by 11 publications

References 8 publications

Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry

Isotope ratio monitoring of small molecules and macromolecules by liquid chromatography coupled to isotope ratio mass spectrometry

Measurement of 34S/32S Ratios of NBS 120c and BCR 32 Phosphorites Using Purge and Trap EA‐IRMS Technology

Simultaneous Identification and δ13C Classification of Drugs Using GC with Concurrent Single Quadrupole and Isotope Ratio Mass Spectrometers*

Contact Info

Product

Resources

About

Measurement of ³⁴S/³²S Ratios of NBS 120c and BCR 32 Phosphorites Using Purge and Trap EA‐IRMS Technology

Simultaneous Identification and δ¹³C Classification of Drugs Using GC with Concurrent Single Quadrupole and Isotope Ratio Mass Spectrometers*