KENT CAMBRIDGE INSTRUMENT COMPANY

Telex 137-337. IN CANADA. KENT CAMBRIDGE LIMITED. Thornhill, Ontario, Canada. (416) 689-8330. Telex 06-217518. CIRCLE 119 ON READER SERVICE ...
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Versatile, 'Go Anywhere' Industrial pH Transmitters

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T a b l e I. F l a m e Characteristics Desirable for M u l t i e l e m e n t Flame Spectrometry Technique

Characteristics

Atomic emission

Potential f l a m e s

Good atomization efficiency for wide variety of elements

Shielded N 2 0 - C 2 H 2

Long residence time in optical

Fuel-rich oxyacetylene

path High temperature for good excitation efficiency Large variation in excitation conditions over small flame region to allow simultaneous excitation and observation of many elements Good atomization efficiency for

Atomic absorption

N20-C2H2

wide variety of elements Long residence time in optical Atomic fluorescence

path

Separated N 2 0 - C 2 H 2

Good atomization efficiency for wide variety of elements Long residence time in optical

Flame sheathed a i r acetylene

path Low background spectral radiance Low concentration of quenchers Low scattering of exciting radiation T a b l e I I . Primary Light S o u r c e s for Multielement F l a m e S p e c t r o m e t r y Technique

Atomic absorption

Approach

Limitations

Single-element hollow cathode lamps Multielement hollow cathode lamps Tandem hollow cathode lamps

Complicated optical arrangement required Number of elements which c a n be incorporated in given lamp limited Limited to three lamps by light

Time-resolved spark Continuum

Kent EIL Series 2830 pH trans­ mitters have lab instrument accuracy, but are rugged and waterproof. Have integral local indicators and standard 0-14 pH/0-800 mV scales —output of 4-20 mA.

Atomic fluorescence

Banks of singleelement electrodeless discharge tubes Banks of pulsed hollow cathode lamps

Optional features include .. . • high/low alarms and controls with relays • any 2, 5 or 10 pH expanded scale • 7201 flow electrode system • ultrasonic cleaning on electrodes Write for complete data to: ΛΜΨ C Î

KENT CAMBRIDGE INSTRUMENT COMPANY

^ 1 ^ Division of Kent Cambridge Corp. 73 S p r i n g S t r e e t , O s s i n i n g , N.Y. 10562 (914) 941-8100 T e l e x 137-337 IN CANADA KENT CAMBRIDGE LIMITED Thornhill, Ontario, Canada (416) 889-8330 Telex 06-217518 CIRCLE 1 1 9 O N READER SERVICE CARD 714 A ·

ANALYTICAL

CHEMISTRY,

Multielement electrodeless discharge tubes

Tunable laser Continuum

An alternative approach to the primary source problem of simultaneous multielement analysis by atomic absorption is the production of a light source which simultaneously radiates resonance lines of a variety of elements, i.e., multielement light sources. Massman (13) studied the factors involved in the production of multielement hollow cathode lamps. Concentric rings of metals retained in a copper or steel sheath have proV O L . 4 5 , N O . 8, J U L Y

1973

losses Less sensitive & less reproducible than hollow cathode lamp Low spectral radiance at short wavelengths & less sensitive than hollow cathode lamp Number of elements which can be incorporated into given lamp limitedmicrowave power supplies Multiple required

No serious limitations except system may become unwieldy for large number of lamps Very expensive at present Low spectral radiance at shorter wavelengths

duced lamps with up to four elements. Since the sputtering rates and melting points of the elements are parameters affecting the production of multielement hollow cathode lamps, it seems unlikely that this approach will yield lamps having a large enough number of elements for true multielement analysis. Strasheim and Butler (14, 15) made specially designed hollow cathode lamps which allow tandem