Computer-controlled multielement atomic emission/fluorescence spectrometer system

Ullman, Alan H.; Pollard, Bruce D.; Boutilier, G. D.; Bateh, Ricky P.; Hanley, P. R.; Winefordner, J. D.

doi:10.1021/ac50050a021

Cited by 25 publications

(19 citation statements)

References 13 publications

(14 reference statements)

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“…The system used was described previously (1). The continuous wave (CW) measurements with DC detection were performed with the same system used for WM but without wobbling the refractor plate.…”

Section: 032/35e2/-mentioning

confidence: 99%

“…The total noise for any AFS individual measurements is given approximately (3) by NT = (NEs~ + Nl)s2 + Nss2 -k Nss2 + Nc,s2 + N ( y 2 + N&s2 + NA+J2 + NEF2 + NDF2 + + ( N B F + NC,F + NbF)' + (NSF + Nc, + NAp)2)1'2 (1) where NEs and NEF = electronic measurement shot (S) and flicker (F) noises, N D S and NDF = detector shot (S) and flicker (F) noises, NBs and NBF = emission background shot (S) and flicker (F) noises, Nss and NSF = scatter shot (S) and flicker All flames were Ar shielded (1,5). Nebulizer system was standard Perkin-Elmer AA 303 pneumatic type (1,5).…”

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confidence: 99%

“…Nebulizer system was standard Perkin-Elmer AA 303 pneumatic type (1,5). = analyte fluorescence shot (S) and flicker (F) noises.…”

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confidence: 99%

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Noise sources in multielement atomic fluorescence spectrometry

Pollard¹,

Ullman²,

Winefordner³

1981

Anal. Chem.

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The multlelement atomic fluorescence-emission spectrometric system (continuum source of excitation) has been evaluated for indlvldual noise contributions as a function of flame type, modulation approach, and atom type. The flames studied included Ar-shielded airlacetylene, Ar-shielded N20/ acetylene, Ar-shlelded N,O/propane, and an air/acetylene flame with a liquid fuel component (Isooctane and jet engine oil). The modulatlon methods included AM (amplitude modulation) and WM (wavelengths modulation) as well as CW (contlnuous wave excltation with DC detection). The elements and wavelengths studied Include Cd (228.2 nm), Mg (285.2 nm), Cu (324.7 nm), Ca (422.7 nm), and Na (589.0 nm); Bi (306.8 nm) was studled in the air/acetylene flame only. Useful concluslons were that the N,O/propane flame was less useful than the two acetylene-based flames, that AM is superior for transitlons wlth wavelengths 5350 nm and WM for ones 5350 nm, that analyte emission/fluorescence flicker noise becomes slgnificant for analyte concentrations above -1OOX the limltlng detectable concentratlon, and that the air/acetylene flame should always be used instead of the N,O/acetylene flame unless atomizatlon is insufflcient to obtaln reasonable signal levels.A signal-to-noise ratio approach is used to evaluate and optimize the multielement atomic fluorescence spectrometer (MEAFS) previously described (1). A review and tutorial discussion of noise and signal-to-noise ratios in analytical spectrometry have already been given (2-4), and so no attempt will be made here to review the basic concepts. In this manuscript, the total measured noise is partitioned between individual noise components; the influence of flame type,

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Section: 032/35e2/-mentioning

confidence: 99%

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confidence: 99%

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Noise sources in multielement atomic fluorescence spectrometry

Pollard¹,

Ullman²,

Winefordner³

1981

Anal. Chem.

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“…Atomic fluorescence occurs when atoms are excited by the absorption of radiation of a suitable wavelength Manual monochromator (8) Single element, with R166 photomultiplier (solar blind) or IP28 with filter ( 13) Computer-controlled slew scan monochromator (9) Multielement, using time division multiplex ( 14) Monochromator with multiple exit slits ( 10) Echelle spectrometer with image dissector (11,12) Oscillating interference filters ( 15) from an external source. Then emis sion occurs at the same or often a longer wavelength.…”

Section: Theorymentioning

confidence: 99%

“…Typical setups are listed in Table I ( [8][9][10][11][12][13][14][15]. Typical setups are listed in Table I ( [8][9][10][11][12][13][14][15].…”

Section: Instrumentationmentioning

confidence: 99%

Atomic Fluorescence Spectrometry

Loon¹

1981

Anal. Chem.

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Synthesis of Chiral Tertiary Alcohols by Cu^I‐Catalyzed Enantioselective Addition of Organomagnesium Reagents to Ketones

Rong

Pellegrini

Harutyunyan

2015

Chemistry A European J

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Catalytic enantioselective addition of organometallic nucleophiles to ketones is among the most straightforward approaches to the synthesis of chiral tertiary alcohols. The first such catalytic methodologies using the highly reactive organomagnesium reagents, which are the preferred organometallic reagents in terms of cost, availability, atom efficiency, and structural diversity, were developed only during the last five years. This Concept article highlights the fundamental breakthrough that made the development of methodologies for highly enantioselective Cu(I) -catalyzed alkylation of ketones using organomagnesium reagents possible.

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Computer-controlled multielement atomic emission/fluorescence spectrometer system

Cited by 25 publications

References 13 publications

Noise sources in multielement atomic fluorescence spectrometry

Noise sources in multielement atomic fluorescence spectrometry

Atomic Fluorescence Spectrometry

Synthesis of Chiral Tertiary Alcohols by Cu^I‐Catalyzed Enantioselective Addition of Organomagnesium Reagents to Ketones

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Computer-controlled multielement atomic emission/fluorescence spectrometer system

Cited by 25 publications

References 13 publications

Noise sources in multielement atomic fluorescence spectrometry

Noise sources in multielement atomic fluorescence spectrometry

Atomic Fluorescence Spectrometry

Synthesis of Chiral Tertiary Alcohols by CuI‐Catalyzed Enantioselective Addition of Organomagnesium Reagents to Ketones

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Product

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Synthesis of Chiral Tertiary Alcohols by Cu^I‐Catalyzed Enantioselective Addition of Organomagnesium Reagents to Ketones