Optical nitrogen-15 analysis of small nitrogen samples with a mixture of helium and xenon to sustain the discharge in an electrodeless tube

Goleb, Joseph A.; Middelboe, V.

doi:10.1016/s0003-2670(00)89211-9

Cited by 38 publications

(6 citation statements)

References 4 publications

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“…After cooling, the surface 01 the glass was degassed with a Tesla coil (Fiedler & Proksch 1975) and the filters were transferred to the sample tubes (Lipschultz 1984). A 2% He/Xe mixture was added to sustain the emission at the low sample pressures generated from the small mass of particle nitrogen (Goleb & Middleboe 1968). The sample tubes were then sealed, combusted at 600°C for 12 h and allowed to cool for 24 h before analysis of the isotopic content of the resulting NZ gas.…”

Section: Methodsmentioning

confidence: 99%

Nitrogen-specific uptake rates of marine phytoplankton isolated from natural populations of particles by flow cytometry

Lipschultz¹

1995

Mar. Ecol. Prog. Ser.

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Phytoplankton were isolated from natural, heterogeneous populations of part~cles in Boothbay Harbor, M a~n e , USA using flow cytornetry with cell sorting to measure true rates of nitrogenspecific uptake of 15N without the bias due to detritus, bactena or other heterotrophs that affects tradltional filtration techniques. After incubation under light or dark conditions with I5NH4+ or "NO3-, particles were either directly filtered or were sorted to isolate phytoplankton and then filtered for isotopic analysis. Nitrogen-specific (pN, t i m e ' ) and absolute uptake rates (mass volume-' time-l) of ammonium were greater for small (3-10 pm) phytoplankton than for larger (10-53 pm) phytoplankton, whereas the opposite was observed for uptake of nitrate. Accounting for pronounced diel variations in uptake from both nitrogen sources, algal growth rates were calculated to be 0.38 d-' on ammonium and 0.05 d -' on nitrate. The absolute rate of NH,+ uptake by all particles as assayed by filtration was approximately balanced by the summed rates of the 2 sorted fractions and the small ( < 3 ).]m) particles that were removed prior to sorting: phytoplankton represented only 50% of the total rate. In contrast, phytoplankton uptake of nitrate represented only about one-third of the total uptake, and the remaining fractions contributed only 10% leaving about 60% unaccounted for. Future applicat~ons of flow cytornetry with stable isotopes could be used to investigate diel variations in p~ and pc (carbon-specific uptake rates) and provide an estimate of phytoplankton growth rates.

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Section: Methodsmentioning

confidence: 99%

Nitrogen-specific uptake rates of marine phytoplankton isolated from natural populations of particles by flow cytometry

Lipschultz¹

1995

Mar. Ecol. Prog. Ser.

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“…Assuming statistical distribution of the nuclides, the above equation (1) can be transformed into the following more convenient form: (3) or (4) Thus, the apparent percentage of nitrogen-15, X ( =X 1 ), in samples having less than 40% enrichment may be expressed as follows {12): (5) For the samples containing more than 20% nitrogen-IS, the equation for the apparent percentage of nitrogen-IS X ( =X 2 ) becomes,…”

Section: Peak Height and The Actual And Apparent Percentage Ofnitrogementioning

confidence: 99%

“…Recently, the method has been improved (2)(3)(4)(5)(10)(11)(12) and applied to agricultural studies and in many other research areas. Emission spectrometry has several excellent points compared to mass spectrometry as follows.…”

mentioning

confidence: 99%

The accurate determination of nitrogen-15 with an emission spectrometer

Yamamuro

1981

Soil Science and Plant Nutrition

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“…The analytical difficulties of using 15N to study nitrogen metabolism have been largely eliminated by the perfection of molecular emission spectroscopy (Faust 1967, Goleb and Middelboe 1968, Liecknamet al 1968) as a method for detection of the nitrogen isotope. The emission spectrometric method for the stable isotope measurement has recently been developed (Ferraris and Proksch 1972, Fiedlerand Proksch 1972, Goleb and Middelboe 1968, Kumazawa and Goleb 1969, Muhammad and Kumazawa 1972, Perschke et al 1971) for routine analysis. However, developments are still needed to apply the method to detect 15N in samples containing submicrogram quantities of nitrogen such as an amino acid or amide separated by thin-layer chromatography.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen distribution studies by emission spectrometry in free amino acids and amides of developing panicle of rice

Muhammad¹,

Kumazawa²

1976

J Plant Nutrition & Soil

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Studien zur Stickstoffverteilung durch Emissions‐Spektrometric in freien Aminosäuren und Amiden junger Reisrispen Die Verteilung von Ammonium‐ und Nitrat‐Stickstoff auf die freien Aminosäuren und Amide junger, sich entwickelnder Reisrispen (Oryza sativa L.) wurde nach Aufnahme durch die Wurzeln ermittelt. Dabei erfolgten die Auftrennungen der Aminosäuren und Amide durch Dünnschicht‐Chromatographie und die 15N‐Bestimmungen mit Hilfe der Emissions‐Spektrometrie. In den Reisrispen fanden sich große Reserven an Asparagin, Glutamin und Glutaminsäure. Die 15N‐Anteile in freien Aminosäuren und Amiden waren bei Zufuhr von 15N‐Ammoniumionen höher als bei entsprechender Ernährung mit Nitrat. Glutaminsäure enthielt einen wesentlich höheren Anteil an 15N‐ und an Gesamt‐Stickstoff als jede andere Aminosäure, was als Hinweis auf die zentrale Bedeutung der Glutaminsäure für die Synthese der übrigen Aminosäuren aufgefaßt wurde. Allgemein waren für Aminosäuren, die primär oder sekundär im Krebs‐Zyklus entstehen, hohe Einbauraten festzustellen, und Aminosäuren mit niedrigem metabolischen turn‐over zeigten geringeren Einbau; dies gilt sowohl für das Angebot von 15NH 4+ als auch für 15NO 3−.

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Optical nitrogen-15 analysis of small nitrogen samples with a mixture of helium and xenon to sustain the discharge in an electrodeless tube

Cited by 38 publications

References 4 publications

Nitrogen-specific uptake rates of marine phytoplankton isolated from natural populations of particles by flow cytometry

Nitrogen-specific uptake rates of marine phytoplankton isolated from natural populations of particles by flow cytometry

The accurate determination of nitrogen-15 with an emission spectrometer

Nitrogen distribution studies by emission spectrometry in free amino acids and amides of developing panicle of rice

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