High-precision continuous-flow isotope ratio mass spectrometry

Brenna, J. Thomas; Corso, Thomas N.; Tobias, Herbert J.; Caimi, Richard J.

doi:10.1002/(sici)1098-2787(1997)16:5<227::aid-mas1>3.0.co;2-j

Cited by 304 publications

(217 citation statements)

References 118 publications

Supporting

Mentioning

211

Contrasting

Unclassified

Order By: Relevance

“…Such a system is commonly called "backflushing," and is operated under computer control. A second system developed by Brenna et al [6] uses a gas-switching rotary valve upstream from the reactor, whereby the GC column effluent is replaced by a stream of clean He. Although conceptually more elegant, this approach has not been widely adopted, probably because of maintenance issues with the rotary valve caused by frequent temperature cycling of the GC oven.…”

Section: Solvent Diversionmentioning

confidence: 99%

“…This is frequently accomplished by the addition of a second, small stream of helium -typically 30 lL/min or less -flowing directly into the IRMS ion source. Peaks of reference gas are added to this carrier stream either by rotary sampling valve [6] or more commonly by an arrangement of moveable capillaries [9,76]. Either combines the benefits of using a single reference gas, whose isotopic composition can be measured very precisely, with the flexibility to introduce standards whenever needed.…”

Section: Standardizationmentioning

confidence: 99%

“…As such, the focus here is on volatile and semivolatile organic molecules. Indeed, elemental analyzers and other devices employing GC for the purification of reaction products are far more abundant, are capable of analyzing both organic and inorganic materials, and are the topic of other reviews [5][6][7]. The second restriction is that of specialized systems designed specifically for measuring isotope ratios with very high precision at or near their natural abundance.…”

Section: Introductionmentioning

confidence: 99%

“…No lesson in isotopic analytical chemistry can be fully coherent without at least some reference to the past and introduction to the vernacular. Only the barest of bones are provided here, with the hope that interested readers will pursue some of the excellent reviews that provide more thorough historical coverage [6,[9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Isotope‐ratio detection for gas chromatography

Sessions¹

2006

J of Separation Science

244

270

View full text Add to dashboard Cite

Isotope-ratio detection for gas chromatographyInstrumentation and methods exist for highly precise analyses of the stable-isotopic composition of organic compounds separated by GC. The general approach combines a conventional GC, a chemical reaction interface, and a specialized isotoperatio mass spectrometer (IRMS). Most existing GC hardware and methods are amenable to isotope-ratio detection. The interface continuously and quantitatively converts all organic matter, including column bleed, to a common molecular form for isotopic measurement. C and N are analyzed as CO 2 and N 2 , respectively, derived from combustion of analytes. H and O are analyzed as H 2 and CO produced by pyrolysis/reduction. IRMS instruments are optimized to provide intense, highly stable ion beams, with extremely high precision realized via a system of differential measurements in which ion currents for all major isotopologs are simultaneously monitored. Calibration to an internationally recognized scale is achieved through comparison of closely spaced sample and standard peaks. Such systems are capable of measuring 13 C/ 12 C ratios with a precision approaching 0.1? (for values reported in the standard delta notation), four orders of magnitude better than that typically achieved by conventional "organic" mass spectrometers. Detection limits to achieve this level of precision are typically a1 nmol C (roughly 10 ng of a typical hydrocarbon) injected on-column. Achievable precision and detection limits are correspondingly higher for N, O, and H, in that order.

show abstract

Section: Solvent Diversionmentioning

confidence: 99%

Section: Standardizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Isotope‐ratio detection for gas chromatography

Sessions¹

2006

J of Separation Science

244

270

View full text Add to dashboard Cite

show abstract

“…This is a feasibility study. It is realized that the precision and sensitivity will not be as good as that obtained using well-established, proven methods such as GC combustion isotope ratio MS, which can achieve RSDs as good as 0.001% [12][13][14][15][16][17][18][19][20].…”

mentioning

confidence: 99%

Determination of carbon isotope ratios in amino acids, proteins, and oligosaccharides by inductively coupled plasma-mass spectrometry

Luong

Houk

2003

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

Carbon isotope ratios ( 12 C/ 13 C) are measured for aqueous solutions of tryptophan, myoglobin, and ␤-cyclodextrin using C ϩ ions from an inductively coupled plasma (ICP) and a prototype twin quadrupole mass spectrometer (MS). 13 C/ 12 C ratios can be determined with a relative standard deviation (RSD) of ϳ1%. This precision is close to the limiting value predicted by counting statistics (1.16%). Spectral interference on 13 C ϩ , presumably from 12 C 1 H ϩ , comes from the incomplete dissociation of myoglobin and/or ␤-cyclodextrin, but not tryptophan. Decreasing the aerosol gas flow rate slightly from that which yields maximum signal eliminates this 12 C 1 H ϩ interference. The count rate of the minor isotope ( 13 C ϩ ) can be artificially enhanced by increasing the voltage of the 13 C ϩ detector, and/or by shifting the ion beam splitter offset from the central axis. Instrumental modifications to the MS that improve the sensitivity are also described. I nductively coupled plasma mass spectrometry (ICP-MS) is a versatile technique for elemental and isotopic analysis. Applications of ICP-MS range from elemental determinations to isotopic analysis in nutrition, clinical studies, geochemistry, environmental studies, and the semiconductor and nuclear industries. ICP-MS has long linear dynamic range (eight orders of magnitude) and detection limits at part per trillion levels for many elements. Most ICP-MS instruments contain a quadrupole or magnetic sector mass spectrometer with a single detector. These are sequential devices that do not measure the various m/z values of interest at precisely the same time. They provide moderate to good precision in isotope ratio measurements, typically 0.05% relative standard deviation (RSD) on ratios close to unity, with substantially poorer precision on large or small ratios [1][2][3][4].Much of the instability in the ion signal is caused by flicker noise from the ICP. This source of noise can be eliminated by measuring the various m/z values at the same time using a multicollector magnetic sector device [5,6]. We have described a unique instrument with two quadrupole mass filters and an ion beam splitter that also eliminates the flicker noise contribution to isotope ratios [7]. Allen and co-workers have analyzed solid copper and steel samples using laser ablation with this twin quadrupole device. The isotope ratio precision reported by Allen et al. was 0.06 to 0.1% for 52 Cr/ 53 Cr, depending on the dwell time and averaging method used [8].This paper evaluates the performance obtained for measurement of carbon isotope ratios from organic compounds at natural isotopic abundance. The ultimate goal is to provide a method for carbon isotopic analyses in bioorganic molecules in aqueous solution. This is an ambitious goal, since carbon is only 1 to 5% ionized in the ICP [9]. Thus, the sensitivity (i.e., count rate per unit concentration) is much lower than that for the metals and metalloids usually determined by ICP-MS, and 13 C is only ϳ1% of 12 C. No more than 0.1% of the analyte ion...

show abstract

Correction algorithm for online continuous flow δ ¹³ C and δ ¹⁸ O carbonate and cellulose stable isotope analyses

Evans

Selmer

Breeden

et al. 2016

Geochem. Geophys. Geosyst.

View full text Add to dashboard Cite

We describe an algorithm to correct for scale compression, runtime drift, and amplitude effects in carbonate and cellulose oxygen and carbon isotopic analyses made on two online continuous flow isotope ratio mass spectrometry (CF‐IRMS) systems using gas chromatographic (GC) separation. We validate the algorithm by correcting measurements of samples of known isotopic composition which are not used to estimate the corrections. For carbonate δ13C (δ18O) data, median precision of validation estimates for two reference materials and two calibrated working standards is 0.05‰ (0.07‰); median bias is 0.04‰ (0.02‰) over a range of 49.2‰ (24.3‰). For α‐cellulose δ13C (δ18O) data, median precision of validation estimates for one reference material and five working standards is 0.11‰ (0.27‰); median bias is 0.13‰ (−0.10‰) over a range of 16.1‰ (19.1‰). These results are within the 5th–95th percentile range of subsequent routine runtime validation exercises in which one working standard is used to calibrate the other. Analysis of the relative importance of correction steps suggests that drift and scale‐compression corrections are most reliable and valuable. If validation precisions are not already small, routine cross‐validated precision estimates are improved by up to 50% (80%). The results suggest that correction for systematic error may enable these particular CF‐IRMS systems to produce δ13C and δ18O carbonate and cellulose isotopic analyses with higher validated precision, accuracy, and throughput than is typically reported for these systems. The correction scheme may be used in support of replication‐intensive research projects in paleoclimatology and other data‐intensive applications within the geosciences.

show abstract

High-precision continuous-flow isotope ratio mass spectrometry

Cited by 304 publications

References 118 publications

Isotope‐ratio detection for gas chromatography

Isotope‐ratio detection for gas chromatography

Determination of carbon isotope ratios in amino acids, proteins, and oligosaccharides by inductively coupled plasma-mass spectrometry

Correction algorithm for online continuous flow δ ¹³ C and δ ¹⁸ O carbonate and cellulose stable isotope analyses

Contact Info

Product

Resources

About

High-precision continuous-flow isotope ratio mass spectrometry

Cited by 304 publications

References 118 publications

Isotope‐ratio detection for gas chromatography

Isotope‐ratio detection for gas chromatography

Determination of carbon isotope ratios in amino acids, proteins, and oligosaccharides by inductively coupled plasma-mass spectrometry

Correction algorithm for online continuous flow δ 13 C and δ 18 O carbonate and cellulose stable isotope analyses

Contact Info

Product

Resources

About

Correction algorithm for online continuous flow δ ¹³ C and δ ¹⁸ O carbonate and cellulose stable isotope analyses