CHAPTER 2 hation 2.1 LIGHT SOURCES The number of applications of lasers as light sources in atomic spectrometry continues to increase, and these are reported in the Sections 1.1.2 and 1.3.4. To justify the general use of AFS rather than AAS, intense stable light sources with good long and short term stability are required. The limitations imposed by currently available sources are largely responsible for the lack of popularity of AFS.EDLs often provide sufficient intensity, but they have gained a reputation for poor stability compared with HCLs. The addition, in 1965, of auxiliary electrodes to HCLs provided an increase in spectral output, but a major limitation of these boosted discharge lumps was that the proximity of the auxiliary electrodes produced a high concentration of charged species in thc region of the sputtering (hollow cathodc) discharge. This limited the magnitude of thc boosting current that could be applied, since excessive line broadening and self-reversal occurred at currents in excess of 100mA.This limitation has been overcome in a demount- able boosted discharge lamp described by Sullivan and Van Loon (490), in which thc water-cooled cathode was in the form of a disc.The charged species formed by the sputtering discharge were swept from that region by a flow of Ar prior to additional excitation by the boosting discharge; thus electrical interaction was minimized. This allowed boosting currents up t o about 500mA t o be used, resulting in high output intensities over narrow line profiles due to the low sputtering currents used.Calibration graphs obtained with this lamp for FAAS showed improved sensitivity and linearity. Detection limits for FAFS were better than those obtained with the old-style boosted-output lamps. A later version of the new lamp was described, which was more suitable for FAFS because the window was placed closer to the discharge (1559). This resulted in a higher numerical aperture (approximately f / 1) and hence further improved fluorescence sensitivity. This lamp had a shorter warm-up time than those of commercial EDLs and non-dispersive FAFS performance was at least as good.Normally, the most successful line sources for volatile elements such as As and Se are EDLs, but a new type of sealed vapour discharge lamp developed by Gough and Sullivan (799, 1678) was reported t o be especially suited t o these elements.The lamp, known as a control!ed temperature-gradient lamp consisted of a vertically mounted tube with an electrode sealed into each end. In operation the volatile element vapours rose slowly from the bottom of the lamp (the anode) and a furnace surrounding the tube controlled the vapour pressure and thus prevented condensation on the cathode.A stable narrow-line output was obtained with reported intensities five times higher than those of EDLs. The performance of the lamp was demonstrated by a detection limit of 16 ngml-1 for As by non-dispersive FAFS. It is well known that the pulsing of hollowcathode Zumps enables higher spectral output to be obtained without serious line broadening.A 6-element HCL was pulsed at 200 mA (duration of pulses 3.2 ms) and provided FAFS detection limits for Ag, Au, Co, Cu, Fe, and Ni of 3 X 10-4, 1.5X 10-4, 6 X 10-4, 4 X 10-5, 6 x 10-4, and 1 x 10-4 ppm, respectively (1950). A circuit for a pulsed HCL power supply has been described (1743). Demountable HCLs frequently employ water-cooling of the cathode to give narrower lines at higher operating currents.Water-cooled HCLs for As and Se (633) were claimed t o have much 3334 Aizdlytical Atontic Spectroscopy reduced warm-up times (only 2-3 min) compared with conventional lamps, and to yield very low detection limits for AAS; e.g., 22 pg for As (197.3 nm) and 40 pg for Se (196.0 nm) with ETA. The reported detection limits of 1.3 and 0.74 ppm, respectively, for these elements in an air/C,H, flame were, however, worse than those normally obtained using EDLs.A further improvement by the same authors (634) replaced the Ne fill gas of the As lamp with a mixture of Ne and H,. They reported enhanced emission, 7-10 times the intensity of a conventional HCL (via the intermediate production of ASH,), which gave a detection limit of 4pg by ETA-AAS.The effect of HCL line-widths on AAS calibration graphs has been investigated (804). Additional references on the preceding topics - 420, 606, 16 13. Commercial electrodeless discharge lamps are more often coupled to r.f. generators than to traditional microwave resonant cavities. Larkins (1 191) has evaluated some commer- cially available r.f. powered EDLs as sources for non-dispersive FAFS.They provided high-intensity narrow spectral lines, and although warm-up times were long (30-60 min) little drift was observed. Walters and Smit (935) found that r.f. powered lamps required thermostatted air sheathing for temperature stabilization. They studied the effects on cmission line profile of temperature, amount of material in the lamp, variation of forward power, and electronic modulation, Peak performance was obtained when the lamps were partly situated in the excitation coil and partly in the thermostatting jacket.These authors have also described a 150 MHz ref. generator for use with EDLs (937). Microwave EDLs acquired in the past a reputation for poor stability. More stable lamps have however been produced by a Simplex optimization of 10 parameters involved in their construction (1 182). Detection limits obtained with these lamps for FAFS were the lowest reported to date.A review of microwave EDLs (441) incorporated a study of fill-gas pressure, amount of filling material, temperature, operating power, etc. Additional references on the preceding topics - 154, 368, 759. The use of an inductively coupled plasma as an excitation source for AFS was investig- ated (1851). It was extremely versatile, since to change elements it was only necessary to spray a different salt into the plasma.Detection limits were generally poorer than those obtained with conventional AFS, but the authors suggested the use of an ellipsoidal reflector behind the plasma to increase the solid angle of emission detected, thus providing better analytical sensitivity.The high cost of an ICP would preclude its use merely as a light source, but in specific instances where line spectral interferences occur in ICP-OES, the fluorescence technique could reduce or eliminate them. The pulsed flashlamp continuum source of Human and Butler (see ARAAS, 1977, 7, Ref. 671), which consisted of a He jet guided spark discharge, has been evaluated for AFS (933). A 5-fold improvement in the detection limits for Au and Pb, compared with those obtained with a 150 W Eimac lamp, was reported. Other references of interest - Continuum source AFS: 413. Flow lamp as a line source: 1662. Laser induced opto-galvanic spectroscopy in a hollow-cathode discharge : 726.Mercury (1 85.0 nm) discharge lamp: 158. Reviews of light sources: 423, 1376, 1969. Selective modulation for sharpening resonance lines: 9 14. Xe arc source correction for light scattering: 1177.Iirstrumentation 35 2.2 OPTICS 2.2.1 Background Correction A lamp combining H, and W sources in the same envelope has been reported, which gave coiztiiiuous spectral emission in the range 190 to 900 nm (1 123).Thus, background correction was extended to those elements with wavelengths greater than 350 nm. Errors in background correction with an ETA have been observed when the radii of the HCL and H, lamp beams were different (635). Wavelength modulation by displacement of a quartz refractor plate is frequently used in emission spectrometers for background correction.A stair-step waveform applied to the plate driver causes a discontinuous wavelength sweep across each analytical line. A digitally programmable waveform generator (1 325) allowed either the complete wavelength range to be swept, or, if the background had already bccn characterized, only the specific wavelengths needed to determine the background were measured; thus a significant saving in analytical time was accomplished. A crystal controlled time-base then allowed each wavelength to be integrated for up to several seconds.The self-drive function generator also providcd a saving in computer overheads, since the computer was only required to collect and process data and not to generate the waveform, A novel method of wavelength modulation for FAFS used a rotating light beam chopper whose four quartz quadrants of different thicknesses provided different degrees of refraction.Square-wave modulation was achieved with a fixed wavelength-scan range (1 374). Additional reference on the preceding topics - 209. Several papers have appeared on the use of Zeeman-eflect AAS for providing back- ground correction when determining trace elements in biological materials by ETA-AAS (170, 612, 613, 909, 1245, 1437, 1785, 1973).Stephens and Murphy (313) have investigated the possibilities of Zeeman background correction in cases of variable background absorp- tion over the spectral multiplet. Additional reference on the preceding topic - 910. Other references of interest - Background correction with photodiode array: 863.Regulated H, lamp power supply: 2047. 2.2.2 Optical Systems A major source of stray light in ICP-OES can arise from the intense cmission lines of Ca and Mg. A band-reflection interference filter centred at 398nm was used to eliminate the Ca 393.4 nm and Mg 396.8 nm lines (1 153). This filter was mounted ahead of the polychromator entrance slit, but where the source of stray radiation was a number of lines or bands spread over a wide wavelength range, band-transmission filters ahead of the individual detectors were used.Wohlers (614) found that although holographic gratings in polychroma- tors reduced stray light generally, interferences from Ca and Mg were not reduced signifi- cantly, It was concluded that the only advantage of holographic gratings was to eliminate ghosts, and this did not justify their general use with KPs.Stray light in FAFS originates from both the source and the flame. Michel et al. (1178) used a double monochromator to reduce flame stray light, the extent of the reduction was dependent on sample type. Source scatter was still significant, however, especially when an air/H, rather than air/C,H, flame was used.When vidicon tubes are used for simultancous multi-wavelength detection, a major limitation is the poor resolution when viewing a wide spectral range. In attempts to obtain3h Analytical A tomic Spectroscopy sufficient resolution, details of some interesting modifications of polychromafors have been published. A vertical array of 6 small mirrors mounted aftcr the diffraction grating of a 0.25 m Czerny-Turner polychromator divided the u.v.-visible spectrum into 6 different 105nm segments (2007).Each segment was then displayed along the horizontal axis at a different vertical position of the 2-dimensional imaging detector. The system provided a spectral resolution slightly better than 1 nm over the range 200-800 nm, which was adequate for molecular spectrometry but would still allow significant spectral interferences if used for multi-element AES. The modification used by Busch et a!.(1707) involved reversing the optical path of a 0.5 m Czerny-Turner polychromator. A multiple entrance slit assembly was placed in the exit plane of the polychromator and this permitted selected spectral regions of 40 nm to be imaged on a SIT vidicon detector mounted in the focal plane of the entrance port (see Section 2.3).Echelle monochromators provide much better resolution than do conventional mono- chromators, but suffcr from “peaking” of the spectral efficiency in the centre of cach ordcr rangc. It has been found that thc efficiency in thc overlap region between o r d m is less than 50% of the maximum on a commcrcial spectrometer (56, 1747).Additional reference on the prcccding topic - 205. A microcomputer-controlled monochromator accessory module, consisting of a pro- grammable exit slit mechanism and a PMT mounted on a moving carriage (453, was attached to a commercial programmable monochromafor. Insertion of a beam-splitter into the optical path of the monochromator produced 2 focal plancs of radiation; one was dctccted via the normal exit slit assembly and the other via the accessory modulc.T h i s systcm could be used for simultaneous dual-element AES, for dctcrmining onc clement with an internal standard, or for simultaneous background correction. Wavelength modulation can compensate for spectral interferences and scatter of exciting radiation in AFS, and can provide increased SNR.This feature has been incorporated into a prcviously described continuum source multi-elemcnt AFS / A E S instrument (see ARAAS. 1975, 5, Ref. 1237) by mounting a quartz rcfractor plate in the slew-scan monochromator (2013). Elements such as Na and K with high wavelength resonance lines (i-e.,, giving pre- dominantly emission signals) were determined with bcttcr SNR than when amplitude modulation of the light source was used.The time-constant of the photon counter, however. prevented thc USC of wavelength modulation frequencies greater than 12.5 Hz and this was not rapid enough to minimize flame background flicker noise. Also, focussing of the optics was adversely affected by thc quartz plate. An improved optical system has becn described (912) for an ETA-AAS system utilizing the Furuday e&ct (see ARAAS, 1978. 8, Ref. 1074). Additional references on the preceding topic - 124, 200, 912. An ingenious application of fibre optics exploited the variation of the speed of light with wavelength through a long optical fibre to provide time-resolved wavelength dispersion (1 363); hence multi-element analysis with a single detector was feasible.A dual-beam arrangement used 2 fibre optics of unequal length to present the sample and reference signals sequentially at the detector. In a second type of instrument a number of optical fibres of different lcngth were used to transmit spatially dispersed light to a single PMT. Other references of intcrcst - Coma dispersion in an Ebert monochromator: 1100.Glass capillary arrays for V.U.V. windows: 1101. Modified spectrometer for timt, wavelength, and spatial resolution of transient signals: 67. Optical system for improved K determination in ICP-OES: 562.Znstrumen tation 37 2.3 DETECTOR SYSTEMS Rapid-scanning photoelectric detectors (e.g., diode arrays and vidicons) generally give poorer detection limits than do PMTs for atomic spectrometry.This is due to their low sensitivity and, in some cases, readout noise associated with scanning the detector. Most workers have favoured their use in multi-element AES rather than AAS, particularly in recent years when using ICP emission sources: though a limitation is the rather narrow spectral range (typically 40nm) that can be viewed if resolution i s to be adequate. The lower resolution requirement of line-source AAS enables a spectral range up to approxi- mately 170 nm to be viewed, and thus elements with resonance lines in the range 200-370 nm could be determined simultaneously.Multiplexing line sources is however difficult, and the spectral lines from a multi-element HCL are often emitted with widely differing intensities.The limited dynamic range of AAS compared with ICP-OES is also a problem for multi- element analysis. Most of the recent work has been directed towards computerized data processing, and data reduction with some associated improvements in analytical performance. Codding (738) examined the precision obtained with a photodiode array AA spectro- meter. The use of a computer for data acquisition and reduction gave precision that was generally similar, though somewhat inferior to, conventional detection systems.Bubert et al. (807, 1473) found that with their 5-element diode array spectrometer (see ARAAS, 1978, 8, Ref. 1065) the SNR was wavelength dependent and they claimed that when high value feed-back resistors were used it was similar to the SNR obtained with PMTs.They used the detector with a GDL for determining Cs, K, Li, Na, and Rb in powdered rock samples with detection limits of 12, 0.3, 0.05, 0.5, and 3.6 ppm, respectively. Also, Al, C, Mg, 0, and Si were determined in limestone. Simplified circuitry and much reduced computational equip- ment have now been described for this equipment (1687). An array of 20 photodiodes with the provision of automatic background correction was used by Boumans (863) as a detector in ICP-OES.Any three of the photodiodes were chosen such that the centre one coincided with a spectral line, while the other 2 detected background, which was thcn electronically subtracted. Diode arrays do not suffer the lag problems of vidicons, and therefore they can be used with pulsed light sources and with ETA devices.Resolution of 0.1 nm with a spectral range of 102nm was claimed (534, 549) when two multiplexed high intensity pulsed HCLs were used for the simultaneous determination of 6 elements by ETA-AAS with independent background correction. Intensified diode arrays were evaluated for multi-element FAES, FAAS, and FAFS by Ingle (198, 734). Using pulsed light sources a 512-point spectrum was obtained in only 5ms. Additional reference on the preceding topic - 57.The first reported use of vidicon tubes for multi-element FAES by Busch and Morrison (ARAAS, 1973, 3, Ref. 623) achieved adequate resolution only by limiting the spectral window to 40 nm. Busch et al. (1707) have now improved the versatility of the system for FAES by using a polychromator in reverse so that the SIT vidicon was mounted in the entrance slit position, while a multiple entrance slit asscmbly in the exit plane allowed selected 40nm windows to be focussed on to the detector.The advantage over the previous system was that any number of 40nm windows could be multiplexed at the detector, and hence careful selection of windows would permit more elements to be determined simultaneously without spectral interference. Detection limits were poorer than previously obtained with this detector and conventional spectrometer, but the new system used fibre optics and their low light throughput was doubtless a disadvantage.Hoffman and Pardue (2007) were able to detect the entire u.v.-visible range (200-800nm) simultaneously with a silicon target vidicon by using a modified polychromator that gave a 2-dimensional stacking of 6 separate 105 nm spectral segments (see Section 2.2.2). Resolu- tion was no better than 1 nm, but if the range was limited to (say) 40 nm pcr segment as38 Analytical Atomic Spectroscopy with thc Busch system, resolution might be sufficient for AES.A limitation was the extra time required to scan 6 segments.A SIT vidicon has been used in conjunction with a slew- scan programmable monochromator for sequential multi-element ICP-OES (1 78, 862). Spectral windows were only 5nm wide and apparently the only reason for using this detector rather than the conventional exit slit/PMT arrangement was to eliminate the need for accurate positioning of the exit slit on the analytical peak; this presumably was at the expense of SNR.An echelle spectrometer with a vidicon detector previously described by Wood et nl. (ARAAS, 1975, 5, Ref. 1377) has been used with a GDL (484, 2054). Additional references on the preceding topic - 825, 827. Thc improved performance of imnge dissector tubes compared with other rapid-scanning devices was described by Pardue and Felkel(206) who used an IDES for multi-element AAS and d.c.plasma OES. Emission performance was similar to that using conventional optics and a PMT, while spectral resolution of 0.04-0.09nm was claimed. Similarly, an IDES has been reported to give detcction limits for continuum source FAFS comparable to those obtained with PMTs (1 659). A computer controlled rapid-scanning FAAS spectrometer with an ID mounted in the focal plane of a 0.5 m Ebert monochromator was described by Aldous (950).A 200 nm spectral window was covered for each grating position, and the instrument was successfully used for the multi-element analysis of potable and waste waters. When a photon counting system is to be used for analytical measurements, characteris- tics of the transfer function relating measured count rate to incident photon flux are important.Increased output linearity can be obtained by adjusting the fraction of the pulses passed by the discriminator, but at the expense of stability and sensitivity. Darland et al. (2000) examined several different photon-counting systems as an aid to optimizing the parameters for given applications.Measurements of pulse-height distribution and linearity wcre shown to provide valuable information about the optimum operating parameters under different experimental conditions, Conventional photon-counting systems are generally considered less suitable than conventional current-mode techniques at high radiative fluxes because of counting losses resulting from pulse overlap. An amplifier / discriminator lprescaler module has been described (2001) which was capable of count rates of greater than 90 MHz and therefore to some extent overcame this limitation.Nau and Nieman (536) solved this problem by combining photon counting and the conventional current-mode detection into a single unit. The instrument automatically switched from one mode t o the other at a pre-determined light level.Instrument control signals, including the selection of photon counting or conventional current mode, amplifier gain, calibration, and counter time-base were provided by hard-wired logic within the instrument, though either manual override or computer interfacing were also possible. Niemczyk et al. (2008) studied the effects of PMT voltage, discriminator setting, and temperature on SNR in photon counting with a PAR Model 1120 amplifierldiscriminator and several commonly used PMTs. They found that under the typical low-light-level operating conditions, the best SNR characteristics were obtained with the highest possible PMT voltage.Cooling the PMT was not considered worthwhile owing to the small improvement in SNR obtained.Resonance detectors contain a low-pressure cloud of analyte atoms that absorb the radiation to be detected; the fluorescence radiation from this cloud is measured by a PMT at right angles to the incident radiation. These dcviccs have good optical efficiency and very high resolving power without the need for a separate monochromator. However, they have never achieved great popularity for AAS because all the atomic absorption lines of an element are detected, and consequently sensitivity for those elements with complex spectra is degraded.Further, as a separate detector is required for each elemcnt this implics high cost. A versatile resonance detector that allowed interchange of elements has been describcd (624). The detector consisted of a flow-through furnace into which desolvated salt particlesInstrumentation 39 were introduced at a low gas flow-rate from an ultrasonic nebulizer system.When an Eimac continuum source was used for AAS, the sensitivity obtained was better than usual for continuum source, but worse than that with a line source. A resonance detector has also been used with a GDL (811, 812). In this case the atomic cloud was produced by sputtering from a cathode containing the elemcnt of interest. Atomic emission interference was eliminated by a pulsing technique.A 4ms current pulse was applied to the detector, which produced an atomic cloud of relatively long lifetime (20-40 ms). By using a gated system, the fluorescence from this cloud was measured a few ms after termination of the current pulse, when atomic emission had subsided almost to zero but the concentration of ground-state atoms was still high.A resolving power of approximately 500000 was obtained. An advantage was that the GDL and dctector both opcrated in an inert gas at low pressure, and so elements with resonance lines in the V.U.V. could be analyzed (e.g., C, P, and S in steel). Multi-element analysis could be accomplished by mounting more than one cathode in the detector and pulsing the cathodes sequcntially.Evaluation of a charge-coupled device as a multi-element detector: 71. Review of new detector systems: 1830. Other references of interest - 2.4 DATA PROCESSING Spectrography, when manually measuring line densities on a photographic plate, can be time consuming and more prone to errors than is OES with photoelectric detectors, With the availability of modern low-cost computers and microprocessors a number of workers have automated these photometric measurements and realized marked improvements in data-processing efficiency. Golightly (6) interfaced a scanning microphotometer to a mini- computer, which rapidly located up to 400 spectral lines, calculated background relative intensities and extrapolated concentrations from stored second-degree polynomial coeficients that described each analytical curve.By using this system with a d.c. arc spectrograph, 64 elements could be determined in 15mg samples of silicate rocks. Bettison and Bundy (783) described a system that allowed a plate to be scanned for the location of 672 lines; the subsequent calculations were completed in 2.5 h plus 30 min operating time.Analogous manual processing by an experienced operator would have taken 6-8h. A Zeiss Schnellfotometer has been automated (824) by interfacing it to a 40 K microcomputer and a floppy disk unit. In addition to a considerable time saving, an improvement in precision was also claimed, Boumans and Bosveld (858) used a computerized microphotomcter in conjunction with a 3.4m Ebert spectrograph for ICP-OES.It was found that the N.B.S. Tables of Spectal Line Intcnsities could be used for line selection provided that appropriate transfcr factors were used to convert the N.B.S. intensities into ICP scnsitivities. Thus, the rclative sensitivities of 452 ICP lines of 71 elcments were computed, together with detection limits for 377 of these lines.The sensitivities of spectral lines of concomitants that interfered with thc most senstive analytical lines were also determined. Computer control of direct reading spectrometers performs several functions, including setting source and software parameters, calibration, data acquisition, data reduction, and outputting the data in suitable format.In addition, the computer may initiate test procedures to ensure that various sections of the spectrometer are operating within specification, and make background corrections and corrections for other interferences. A general discussion of software requirements for performing most of these functions has been prcscnted (1383), and customized systems have been described for ICP-OES (589, 1019) and spark source or ICP-OES (60 1).A time-shared software system for several direct-reading spectrometers was reported (1 384) that allowed FORTRAN programs to be executed simultaneously with40 Analytical Atomic Spectroscopy instrument-control programs. A general purpose minicomputer could control up to 4 spectrometers from 1 or 2 independent graphics terminals.Microprocessor control of commercial AA spectrometers is now standard on the more expcnsive instruments. Several systems have been described (282, 1021, 1957, 2005) including two that had facilities for processing transient signals obtained with electrothermal atomizers (96, 130). The Perkin-Elmer Model 5000 AA spectrometer (see ARAAS, 1978, 8, Section 2.4.2), itself a microcomputer controlled instrument, was interfaced to an external computer (79, 1045).This provided increased capabilities, such as high-speed characteriza- tion of transient signals, automatic background correction in FAES by averaging readings either sidz of the analytical line, and storage of operating parameters. The interfacc was suitable for computers using either the BASIC or FORTRAN languages.Additional references on the preceding topic - 483, 2069. Other references of interest - Algorithm for use with a programmable calculator to process AES data: 1465. Confidence limits for calibration curves with non-uniform variance of data: 2051. Correlation and Fourier transform methods for measurement and analysis of spectral data: 61.Data collection for a microdensitometer: 287. Factors affecting line choice in spectrography: 147. Mathematical expression for the emulsion calibration curve : 1724. Microcomputer controlled monochromator accessory module for dual-wavelength AES: 455 (see also Section 2.2.2). Microprocessor controlled readout system for PMTs: 597. 2.5 COMPLETE INSTRUMENTS 2.5.1 Emission Instruments Plasma source direct readers are now firmly established for routine multi-element analysis.Disadvantages, however, are the compromise operating conditions necessary when several elements are determined simultaneously, and the difficulty of quickly changing elements in the analysis programme, An emerging trend is towards compact and more versatile instru- ments where rapid sequential multi-element analysis is accomplished by using a program- mable slew-scanning monochromator.These instruments are likely to be competitive with AA spectrometers in many cases, and if more than 5 elements are being determined per sample the ICP instrument can provide a faster sample throughput than a fully automated AA spectrometer (548, 879). In addition the versatility of a scanning monochromator allows alternative lines to be easily selected in cases of spectral interference.Perkin-Elmer have produced a dual-purpose ICP-OES /FAAS instrument by coupling a Plasmatherm ICP to a Model 5000 AA spectrometer (1050). The instrument has a stepping-motor driven monochromator, automatic background correction and it is interfaced to an external com- puter.Detection limits with the ICP were generally equal to or better than FAAS and fcwer chemical interferences were evident, but with a spectral band pass of 0.03nm some spectral intcrfcrences were cncountcrcd. Claimed precision was better than 1 %. A rapid-scanning computer controlled ICP spectrometer has been developed by Tnstrumentation Laboratory (551, 864, 865). The programmable doublc monochromator is able to step-scan the spectral range 189-900 nm in only 13 s.The avcrage time to drive from one wavelength to the next is only 3 s, and when each line is integrated for 2 s, 10 elements can be. determined per min. The double monochromator (resolution 0.02 nm) is claimed virtually to eliminate stray light and other types of spectral interference can be compensated for by automatic background correction, which measures and subtracts the background onInstrumentation 41 both sides of the analytical line.An optional second double monochromator allows the number of elements in a given time to be doubled, or it can be used for monitoriiig an internal standard. The optimum viewing position in the plasma can be selected for each element as part of the analysis programme.Haraguchi et al. (178, 862) described a pro- grammable monochromator with a SIT vidicon detector coupled to an ICP source (see Section 2.3). Additional references on the preceding topic - 343, 561, 1300. A 1.5 m Paschen Runge type direct-reading spectrometer has been designed (101 11, which it was claimed allowed the analytical wavelcngths to be changed far more rapidly and easily than in conventional instruments. This instrumcnt uscd dual holographic gratings giving a spectral coverage from 180-500 nm with a linear dispersion of 0.27 nm/mm.Other references of interest - Automatic sampler for a commercial flame photometer: 691, Automatic sampler for a d.c. plasma echelle spectrometer: 81, 208. 2.5.2 Absorption Instruments The multi-element A A spectrometer developed by Salin and Ingle (ARAAS, 1978, 8, Ref. 125) has now been described in more detail (136). Radiation from HCLs, sequentially pulsed at 12.5 Hz, was multiplexed and directed through a monochromator. A mask containing appropriate exit slits was mounted in the focal plane to allow 4 elements to be determined. All radiation was then focussed by means of a mirrored funnel onto a single PMT.The signal for each element was distinguished and integrated by a time-multiplex procedure. The performance of the instrument was evaluated (137) and detection limits were within a factor of 2 of detection limits obtained by conventional single-channel AAS. The poorer SNR with the multi-element system was attributed to stray light, the use of beam splitters, and the pulsing cycle that reduced absolute light levels and hence caused the relative shot noise to increase.The system was also used with an ETA (765) and gave multi-element detcction limits for Cd, Mn, and Pb of 0.2, 2, and 8 ppb, respectively ( 5 pl aliquots). This is probably a better approach to multi-element analysis than using vidicons and SSIDs with their inferior response characteristics, but the use of an image dissector tube would overcome thc need for the mirrored funnel with its stray light problems.This detector has similar SNR perform- ance to a PMT and it would not be necessary to pulse the light sources. Aldous (950) con- structed a multi-element AA spectrometer with an ID mounted in the focal plane of a 0.5 m Ebert monochromator. The instrument was able to monitor a spectral range of 200nm (see also Section 2.3).The versalility provided by a double beam dual-channel A A spectrometer has been described previously with respect to the Instrumentation Laboratory Model 751 (sec ARA AS, 1977, 7, Refs. 1054, 1063; 1978, 8, Refs, 332, 1256). This instrument has now been further updatcd by incorporating a video display (621), as on the Model 551.In addition this new instrument, the Model 951, has achromatic lenses, hence the focal lengths remain constant over the wavelength range 185-860 nm. This instrument was used with a graphite furnace (523) equipped with the automatic aerosol-type sampler (see ARA AS, 1978, 8, Ref, 1354) for the simultaneous determination of Cd and Pb.An additional feature of the instrument, useful for analysis by ETA, is that during the use of background correction, the background absorption and the total absorption (AA + background) can be displayed simultaneously on the video screen. A microprocessor dual-channel instrument has been constructed from commercial components (1930) and used for the simultaneous determination of As and Se in natural water.A throughput rate of 37 samples per hour was claimed.42 A nary tical A t omic Spectroscopy The very high resolving power of echelle monochromators has made continuum source AAS a practical technique. A continuum source echelle wavelength-modulated AA spectro- meter, as described previously by O’Haver and co-workers (ARAAS, 1976, 6, Ref. 596; 1978, 8, Ref. 630), was used with ETA for the determination of 8 trace metals in coal (1335). A multi-element version of the instrument has now been developed (80, 207, 552, 1645). The echelle monochromator was converted to a 20-channel direct readx by inserting a multi-slit cassettc in the focal plane. Background correction and double beam operation were available for all channels and data wcrc output through a 16-channel multiplexed A / D converter interfaced to a dedicated computer.The data acquisition rate was sufficiently fast to permit 100 source-compcnsated background corrected absorbances per second to be measured. Transient events from an ETA could thus be detected. For this, each channel was sampled at a rate of 1 kHz, data being stored immediately on a disk and then removed and processed at the end of the atomization cycle, Detection limits with a flamc were said to be similar to those of conventional AAS above 280nm, but slightly poorer at shorter wave- lengths.The system was used to determine Cr, Cu, Pb, and Zn in body fluids (163). This is probably the most promising approach yet to multi-element AAS, and the system would be useful where AAS methods are already established for determining several metals in the same sample, especially if the continuum source can be improved to provide better SNR at low wavelengths, Additional reference on the preceding topic - 1909.Routh and Bennett (568) described two further new Varian instruments with micro- computer control, providing signal handling and data reduction, and control of instrumental parameters.A new hydride generation accessory suitable for As, Bi, Ge, Sb, Se, Sn, and Te has also been described (993). A new instrument, manufactured in Australia and marketed in the U.K. by EDT Research, is the GC SB900. This compact lightweight low-cost instrument may well be suited to teaching or mobile field testing laboratories. Optional background correction, calculator and hydride generation units are available. Zeeman-AAS, while providing high quality background correction with only a single light source, suffers from the limitation of low analytical sensitivity unless strong magnetic fields are used.An instrument has been described, however, that used a 50Hz sine-wave modulated electromagnet (908, 1297), and sensitivity was claimed to be similar to that of conventional AAS, while curvature of calibration graphs was no more pronounced The magnet consisted of 200 turns of anodized aluminium around a 40 X40 mm core of lamin- ated transformer plate.An 800W power supply delivered up to 25A and provided field strengths up to 10 kG in a 12 mm air gap, which accommodated an ETA between the 10x30 mm pole pieces.The analytical signal was obtained from the log-ratio of the intensities read at zero field and maximum field, respectively (100 Hz modulation). 2.5.3 Fluorescence Instruments A computer-controlled multi-element AFS/AES spectrometer using an Eimac continuum source slew-scanning monochromator and photon counting was previously described by Winefordner et al.(ARAAS, 1975, 5, Ref. 1237). The instrument has now been modified (2013, 1917) by incorporating a quartz refractor plate to allow wavelength modulation (see Section 2.2.2). A continuum source AFS/AES instrument described by Brinkman et al. (1733) was interfaced to a programmable calculator, which allowed the 0.3 m mono- chromator to scan to a programmed set of wavelengths. Data collection and processing were also performed automatically.Although sequential multi-element analysis was feasible, theInstrumentation 43 instrument was used in the single-element mode because of poor long-term stability. The only advantage over conventional single-element systems was that changing from one element to another did not require the source to be changed. Typical detection limits were 0.3, 0.08, and 0.02ppm for Cd, Cu, and Mg, respectively; these are slightly inferior to those normally expected by continuum source FAFS.Salin and Ingle (494) have adapted their time-multiplex AA spectrometer (see Section 2.5.2.) for multi-element FAFS to give better than 1% precision.Table 2.5A - COMMERCIALLY AVAILABLE EMTSSION SPECTROMETERS P P Supplier Reciprocal Focal nm oer mm range/nm m Model Type c~~q;,,$s dispersion/ Wavelength length Type of Source Special features Applied Research Quantometer Laboratories Ltd., 34000C Wingate Road, Luton, Beds., England Applied Research Laboratories Ltd., En Vallaire CH-1024. Ecublens/Lausanne, Quantometer Switzerland 34000D Applied Research Laboratories Ltd., 9545 Wentworth Street, Quantometer P.O.Box 129, B34000C California, U.S.A. Societe Francais d'lnstruments Controlee d'Analyses, B.P. No. 3, Quantotest F 78320, Le Mesnil, 36000 St. Denis, France DR 48 0.465 0.520 or 0,310 0.930 or 0.465 190-820 1.0 DR 48 As 34000C As 34000C As Low voltage high voltage and/or d.c. arc 34000C and/or DR 60 As 34000C As 34000C As As 3400OD 34000C DR 10 0.70 200-400 0.3 Low voltage Full computer control to provide direct concentration print out; full range of options including dual floppy discs, VDUs, fast printers, remote terminals and computer links etc; twin stand facility including Ar, air, hollow cathode, rotrode, plasma etc.Full computer control to provide direct concentration print out; optional local and remote printers, Ar or air excitation stands As 3400CYC, twin stand facility including Ar, air, hollow cathode, rotrode, glow discharge etc, allows for expansion to include a large number of elements and offers comprehensive computer options to handle multiple and complex alloy programmes Small transportable Quantometer with GO-NO GO inspection type electronics Baird Corporation, Spectromet DR 30 0.6 or 0.3 210-590 1.0 Arc or spark; Compact, low-cost direct reader with 125 Middlesex 1000 modular minimum air-conditioning requirements; Turn pike, Bedford, MA 01730, alignment manual master monitor to check slit U.S.A.Spectrovac Baird-Atomic Ltd., 1000 Warner Drive, Spr i ngwood Industrial Estate, Rayne Road, Braintree, Spectromet Essex CM7 7YL, I I England Spectrovac II DR 30 0.6 or 0.3 173-767 1.0 Arc or spark; Compact, low-cost direct reader with 5 modular minimum air-conditioning requirements; a logarithmic read-out; manual master monitor to check slit alignment; dual stand option % DR 60 0.294 190-432 2.0 As Spectromet Automatic optical servo monitor 0.59 190-863 1000 continuously maintains correct slit alignment; logarithmic read out; manual master monitor to check slit alignment; length; dual stand for Ar and air avai la ble i n vacuum 3 temperature-compensated fixed focal 5' DR As Spectromet As Spectromet 11; all photomultipliers 5 1000 0 2 2 0.29 173-432 2.0 60Jarrell-Ash Division t 78-090 Fisher Scientific Co., 590, Lincoln Street, Waltham, MA 02154, 70-310 U.S.A. 420-970 1.5 * 21 0-485 180-3000 180-1500 3.4 180-750 200-6000 0.75 1.0 or 2.0 - 75-1 50 Various availaple in ‘Varisource unit incl.spark, low and high voltage d.c. arcs. -Also versatile controlled wave- excitation source. 96-750 96-785 1500 70-314 Phot. - 1.1 or 0.54 Phot. - 1.0 or 0.24 depending on grating Phot. - 4.4 to 1.1 3.2 to 0.8 1.6 to 0.4 DR DR DR Up to 50 0.54 Up to 50 0.54 Up to 60 0.56 or 0.28 0.34 or 0.17 DR 30 As 70-310 168-500 0.75 As above except 168-500 0.75 controlled \ electronically J peak current 200-800 or 190-400 200-510 or 1 - 5 As above 190-250 As 70-310 3.4 As above Wadsworth Spectrograph; 20 in.camera. Choice of three gratings; N2 purging extends range to 175 nm; optional accessories permit use as direct-reader or scanning spectrometer Computer controlled Choice of 2 gratings Easy interchange to photographic (70-31 0) version I Labtest Equipment 31 0 DR 60 max 0.56 190-900 1.5 Co.Ltd., 11828 La Grange V25 DR 40 max 0.46 170450 1.0 Avenue, Los Angeles, 21 00 DR 30 max 0.46 188-455 1.0 CA 90025, U.S.A. 71 DR 74 max 0.52 170-900 2.0 “Transource’ high-voltage- triggered discharge,. Low- voltage-triggered d.c. arc; ICP all models source for isolution analysis Wavelength in first order: CRT; teletype printer or computer read out systems; dual air/inert gas and solution excitation stand: V25 vacuum for C and S in ferrous materials; ICP can be used on M.B.L.E., t Philips PV Rue des Deux Gares 8300 80, Vacuum 8-1070, Brussels, Belgium Philips Analytical Department, Pye-Unicam Ltd., York Street, Cambridge CB1 ZPX, Philips PV England. 8350 Air DR 60 0.55 170-430 1.5 Triggered (80 lines) or capacitor 0.46 discharge.“Monoalternance discharges” up to 500 Hz; d.c. arc, glow discharge, hollow-cathode DR 40 0.46 177-410 1.0 As for PV 8300 Optional dual air/Ar excitation stand; choice of programmable calculator and computer configurations with dual cassettes or floppy discs; rapid printer; VDU extension options Integrated spectrometer system, including source and readout options as for PV 8300 - t No up to date information supplied.P !ATable ZSA- COMMERCIALLY AVAILABLE EMISSION SPECTROMETERS- continued Supplier Reciprocal Focal nm per mm range/nm m Model Type chNaq;Afls dispersion/ Wavelength length Type of Source Special features ~ Rank-Hi lger Ltd., E 1000 DR 60 0.293-1.155 156-880 1 -5 Various, including Solid-state electronics; microprocessor Westwood, Margate, Polyvac high repetition control available.Dual gratings give 12 Kent CT9 4JL, condensed arc, standard systems to select optimum England ICP, GDL dispersion and wavelength coverage. Special grating if required; dual spark stands microprocessor control available: air or inert gas discharge stands E 960 DR 36 0.546 or 0.741 174.0-447-7 0.75 As ElOD0 Curved entrance and exit slits: Spectrametrics Inc., 204 Andover Street, Andover, MA 01810, U.S.A.AE2 Phot, DR 1 0.06 190-800 0.75 Plasmajet Optimized AE system using a high DRlO DR 20 0.06 190-800 Plasmajet dispersion, high -energy-throughput (inter- chanseab le echelle spectrometer and a high temoerature plasma iet excitation source cassettes) Techmation Ltd., Plasma jet, flame Built ,in computer 58 Edgware Way, ES 9 Phot.- 0.06 19&800 0.75 or arc stand Edgware, Middlesex HA8 8JP, RS 1 DR 1 0.06 190-800 0-75 AS ES9 England (variable wavelength) SDex Industries Inc.. 1870 Scan/Phot. - 1.6 175-1280 0.5 Mu It i-purp ose unit 3880 Park Avenue, U.S.A. Metuchen, NJ 08840, 1702 Scan/Phot. - 1.1 175-1500 0.75 1704 Scan/Phot. - 0.8 175-3500 1 - 0 Glen Creston Instruments Ltd., 1802 Scan/Phot. - 0.8 1&&1500 1 - 0 Direct reading accessory available 16 Carlisle Road, London NW9 OHL, 1269 Scan/Phot.- 0.65 180-1500 1-26 9 Very high resolution England .1" 2 German Democratic multiplying as required; automatic 3 B 2 2 2 2. VEB Carl Zeiss Jena, PGS 2 Phot. - 0.74 or 0.37 200-2800 2.075 Arc or spark Atlas for spectra evaluation; wide choice -, 69 Jena! Carl-Zeiss Str. 1, resolving power; dispersion doubling or $ Republic, transport of cassette; wavelength scale 6. Carl Zeiss Scientific the spectra; wide range of accessories h Instruments Ltd., P.0. Box 43, microspectral analyser 2 Elstree Way, Boreham Wood, Herts. WD6 INH, c, England of precision diffraction gratings; high for quick orientation of the user within available including LMA-10 laser-Table 2.5B - COMMERCIALLY AVAILABLE PLASMA SPECTROMETERS Generator Special features No.of Reclprocal Focal Operat- Type of Type of Type of Supplier Model Type channels “ , p ~ ~ i ~ ~ Output ,i:2 Spectrometer grating nebulizer Power quency/ M Hz Applied Research Quanlometer DR 48 0.930 or 0.465 1.0 2 kW 27.12 Czerny-Turner Ruled Concentric Full computer control to Laboratories Ltd.t 34OOO/lCP or 0.310 replica glass provide direct concentration print-out; full range of options including dual floppy discs, VDU. fast printers, remote terminals and computer links etc. Quanlomepr Scan/DR unllmlted 0.80 1.0 2 kW 27.12 Crerny-Turner Ruled Concentric Automated scanning grating 35000C 0.60 replica glass for waveleng:h.range studies, qualitative analysis on chosen spectrum lines. Full computer control Baird Corporation t Plasma DR 60 0.66 1.0 2.5 kW 27.12 - - - One metre polychromalor with 120 exit slits in a,rigid,focal curve. Da:a aquisition is controlled by a Tektronix 4052 graphic computing system lnstrumenlal ion 100 Scan - 2 . 5 - 2 kW 27.12 Ebert - - M;crocompu:er co;ltrolled Laboratory Inc.Q (Double) scanning double mono- chromator for sequential multi-element analysis; 0.50 profile facilities and 0.40 electronics providing Spectrornet instructions for programming aDoear on video diSDlaV with single keystroke operafion; emission profiles of analytical line appear on video screen for selection of wavelength, of background correction, of inter-element effects and observation of spectral interferences: all circuitry for r.f.power generation, monochromator optics and microcomputer are built into the ins:rument Jarrell-Ash Div., 96975 DR up to 50 0.54 0.75 2 kW r.f. - - - Computer control variable Fisher Scientific channel; concentration print Co. Ltd. t $ out 96-988 OR up t o 5 0 0,54 0-75 - - - - - Computer control; N+l channel scanning attachment, spectrum shiftcr attachment for automatic background Correction; special K and L I channels; data management system New equipment since publication of Volume 8 t No up to date information supplied t Address as in Table 2.5A § Address as in Table 2.5CTable 2.5B - COMMERCIALLY AVAILABLE PLASMA SPECTROMETERS- corztinued h -- Generator Speclal features No.o, Reciprocal Focal Operat- Type of Type of Type ot Supplier Model Type channels ~ ~ p ~ ~ i $ ~ Output i:: Spectrometer grating nebulizer q;zY/ Power Jobin-Yvon t JY 38P Division d'lnstruments, 16-1 8 Rue du Canal, 91160 Longjumeau, France EDT Research, 14 Trading JY 48P Esiate Road, London NWlO, England Kontron GrnbH,, t Plasmaspec 8057 Eching bei System 3 Munchen.Oskar-von-MiIier Plasmaspec Str. 1, System 4 West Germany Scan - - 1.0 Plasmatherm Czerny-Turner Replica Crossflow or Large operative monochromator 1.5 kW 27.12 holographic concentric ( f 5-4 grating size 120x140 2.5 kW glass, or mm) Manual or computer 5 kW ultrasonic conlrolled; constant time Durr-Jobin-Yvon integration or i n ratio mode 2.2 kW 56 4 kW DR 48 0.45 1.0 As Paschen- Master As above Air or vacuum; 86 positions of 0-58 above Runge holographlc photomultipliers.fully 0.69 automatic read-out computer 0.80 option 0.8-1.6 1.0 4tO 27.12 - Scan - 7 kW 7 kW 4t0 27.12 - OR up to 30 0.23-0.46 1.0 - - General purpose - - General purpose Labtest Equipment Plasmascan Scan - - 0.35 2 kW r.f. Czerny-Turner Holographic Crossflow or Microprocessor control. co. * 700 concentric enclosed sample pumping glass, or system, computer read-out ultrasonic system M.B.L.E.t * Philips DR 60 0.55or 0.28 1.0 - r.f. - - - Wavelength range covered In PV 8210 (50 lines) 1st order; remote controlled roving detector; read out by printer, teletype or digital computer systems Integrated spectrophotometer Philips 40 0.695 or 0.35 1.0 - system with built-in source and PV 8250 0.59 or 0.35 read-out options as for PV8210 E \1 2.Phllips DR 40 0.46 1.0 - r.r. - - - Integrated spectrometer system r, PV 8350 including source and read-out a, k Air 0.92 or 0.46 0.46 or 0.23 options as for PV 8210 OR r.f. - Rack- +iilger Ltd., * E 1000 Polyvac DR 60 0*293-1*155 1.5 - r.f. Paschen- Holographic Crossflow or Solid state electronics; dual Runge concentric gratings give 12 standard glass systems to select optimum dispersion and wavelength coverage; special grating I t required; dual spark stands; microprocessor control available E D60 DR 36 0.546-0.741 0.?5 - r.f As above - As above Curved entrancs and exit silts; microprocessor control availablePerkin-Elmer ICP5000 * Corporation 9 Scan - U.V. 0.65 0 . 4 2.5 kW 27.12 - VIS 1.3 Holographic Concentric Complelely au:omated 2 glass seqwntial ICP system can 2 anaiyse up to 20 elements in an operator selectable mu?i-elernent croxamme: analytical parameters ' including wavelength selection, background increment selection and signal handling are programmable ar.d s!orable via standard minicomputer; optical path purgeable permit!ing analysis to 175 nm; optional HGA-500 furnace and gas control systems permit inslrument lo operate as completely automated ICP, flame AA and furnace AA system; ICP sectlon retrofitable t o existing Model 5000 AA speclrophotorneters 0.06 0.75 - d.C.- Echelle - Optimized AES system using Inc. $ Ill inter- As above high-dispersion throughput; Spectrametrics Spectraspan Pho:o/DR 20 integral microprocessor - d.C. - - - High sensitivity even in changeable cassettes - - 0.75 presence of complex matrix solutions with solid contents up to 20% m / V Spectraspan - 1v P W New equipment slnce publication of Volume 8 $ Address as in Table 2.5A 5 Address as In Table 2.5CTable 2 .X - COMMERCIALLY AVATLABLE: ATOMIC ABSORPTION SPECTROMETERS model ~~~~~~~~ Resolution Wavelength Read Automatic Type Of beam nm per mm /nm range/nm out background data correction output Supplier Special features Baird Corporation, 125 Middlesex Turnpike, Bedford, MA 01730, U.S.A.Baird Atomic Ltd., Warner Drive, Springwood Industrial Estate, Rayne Road, Braintree, Essex CM7 7YL, England A51UO Single 3 - 0 0 - 1 186-860 Digital Dz HCL Bit parallel Automatic background correction; BCD (TTL 4-lamp turret; auto zero; integration; levels) curve correction; wavelength scan; flame ignition; gas safety devices; lens optics; emission and fluorescence; optional microprocessor control for up t o 8 standards with re-slope facility, illuminated status indication and date/time clock A3400 Single 6.0 0.2 190-860 Meter or - Digital 4-lamp turret; auto zero; curve correction; integration; flame ignition; wavelength scan; emission and fluorescence; optional microprocessor control for up to 8 standards with re-slope facility; illuminated status indication and date/time clock GBC Scientific GBC Single - 0.5 190-900 Digital - IEEE-488 Dimensions : length 700 mm; Equipment, SB900* width 200 mm; height 225 mrn; Pty.Ltd., optional background correction 7/63. Park Drive. bandenong, . Victoria 3175, Australia EDT Research, 14 Trading Estate Road, London NWlO 7LU, England Hitachi Ltd., t 170-10 Single 2.25 0.4 i90-9ao Nissei Sangyo Co.Ltd., - - Mori 17th Building, 26-55 Toranomon. 1-chome, Mi n ato-Ku, Tokyo, Japan Nissei Sangyo Instruments Inc., 392 Potorero Avenue, Sunnyvale, CA 94086, U.S.A. 70-30 Single ,2.25 0.4 190-900 70-50 Double 2.25 0.1 190-900 70-70 Double 2.25 0.1 190-900 - Meter/ digital optional - Polarized - Zeeman Single lamp mounting, NzO-air simultaneously exchanged; concentration read-out; continuously variable time constant Concentration read-out; time weighted signal averaging; AAS/AES measurement; auto zero; NzO-air simultaneously exchanged Base-line drift correction; curve corrector; time-weighted signal averaging; auto zero Background correction to 1 - 7 absorption unitsNissei Sangyo GmbH, 4 Dusseldorf, Am Wehrhahn 41, West Germany Instrumentation Laboratory Inc., 68 Jonspin Road, W Ilmington, MA 01887, U.S.A. 951* Double/ 2.5 0-04 180-1000 CRT DZ arc in RS232C Microcomputer controlled; calibration si m u I t an- using up to 5 standards; read-out will eously display two elements simultaneously A, 6 , A/B or ATB; jnternal standard and non absorbing line background correction; VDU displays standard signals; automatic gas box is standard feature, optional 4-lamp turret, wavelength scan and built-in alphanumeric printer dual video both channels curve linearized in both channels channel Instrumentation 551 Laboratory (UK) Ltd., Kelvin Close, Birchwood Science Park, Warrington, Cheshire, England 257 Double 2.5 Double 2.5 0.04 180-1000 CRT - video 0.04 180-1000 - RS232C RS232C Microcomputer controlled; calibration curve linearized using up to 5 standards; memory will store up to 10 calibration curves simultaneously; VDU displays standard conditions for each element, the working curve and will show transient signals; fully automated fail-safe gas-box is standard feature; optional background correction, 4-lamp turret, wavelength scan and alphanumeric printer Microcomputer controlled; calibration curve linearized using 2 standards or 5 standards (optional); fully automated gas-box is standard feature; optional background correction; 4-lamp turret, wavelength scan and alphanumeric printer As for 257 m icroprocessor control led, auto-zero; auto conc.; auto curve with up to 3 standards; peak height; peak area, integration time selectable from 0.2 to 60 s; statistics; flame i,gnition optional auto NzO switching and burner head safety interlocks; optional flame and pressure sensing by microcomputer burner control automatic gain control; auto NzO switching, burner head safety interlock; optional DZ arc background correction with automatic intensity RS232C 157 Single 2.5 0.04 180-1000 - - Perkin-Elmer 2280" Single 1.6 0.2 190-860 Digital DZ arc EIA-RS-232C High energy optical system, Corporation, optional Main Avenue, N orwa I k, CA 06856, U.S.A.Perkin-Elmer Ltd ., Beaconsfield, Bucks, HP9 10A, England 190-860 Digital DZ arc EIA-RS-232C As model 2280 but all mirror optics; optional (continued) control ur t No up to date information supplied * New equipment since publication of Volume 8 c 0.2 2380* Double 1.6Table 2.92- COMMERCIALLY AVAILABLE ATOMTC ABSORPTION SPECTROMETERS - continued Single/ Reciprocal Automatic Type of beam nm per mm correction output Supplier Model double dispersion/ ~ ~ ~ ~ ~ ~ ! h 'tid background data Special features (continued) 4000* Double 0.65 0.03 170460 Digital - 1.3 170-900 Bodenseewerk, Perkin-Elmer & Co..GmbH t Postfach 1120, D7770 Uberlingen, West Germany 5000 400 Double 0.65 1.3 Double 1.3 0.03 17M60 Digital - 170-900 0.2 19e860 Digital - 2 way E I A-RS-232C 2 way E IA-RS-232C BCD 410 Double 1/1.6 0.17/0.27 19&860 Digital - - 422 Double 1.3 0.2 190-860 Digital - EIA-RS-232C 432 Double 1/1-6 0.17/0.27 190-860 Digital - - Semi-automated sequential AA system; automatic gain control: instrument can analyse up to 6 elements with little operator participation; analytical parameters, including standardization and signal read-out can be entered and stored internally; digital stepper motor wavelength selection; flame ignition, auto NzO switchover, burner head interlock; optional flame and pressure sensing by microcomputer burner control; optional double-beam background correction for all U.V.and visible wavelengths with automatic intensity control; lamp turret available Completely automated sequential AA system; instrument can analyse up t o 6 elements with minimal operator participation; all analytical parameters, including lamp current, wavelength selection, resolution, gas flows, standardization and signal read-out can be entered and stored using magnetic cards: optional double-beam background correction for all U.V.and visible wavelengths; when used in conjunction with HGA 500 it will provide sequential analysis for up t o 6 elements with the same analytical ease as flame; when used with ICP-emission accessory it will provide sequential multi element analysis for up to 20 elements with operator selectable background parameters Auto zero, auto concentration, integration, curve correction, automatic flame ignition As model 400, but with double-grating monoc hromator As model 400, but with microcomputer electronic key board operation: linearization with up to 3 standards As model 422, but with double-grating m on ochr omat orPye-Unicam Ltd., SP 2900 Double 3 . 3 0.2 190-850 Digital D1 arc BCD 4-lamp magazine; auto zero; integration; 2 standard curve correction; peak-height measurement York Street, with timer; peak area; emission: Cambridge, 0-10 V fast analogue output (0-1 A), CB1 2PX, England 10 mV output for integrated or peak-height reading; simultaneous background Correction as accessory Data d Centre SP 9 Single 4.7 SP 9 - Computer 0.2 190-850 Digital DI HCL - Fully microprocessor controlled data processing by programmable calculator; 3 types of curve correction, statistics, standards additions and other data handling; full calculator ability retained Eight models available with combinations of 4-lamp turret: gas control module with full safety interlocks; scale expansion, 2-standard curvature correction, burner interlock, data output for SP9 computer CO-2V for 0-2 V plus various status and control signals, and 0-10 mV (0-1 A) analogue output as standard Calibration with up to 5 standards i n fixed or variable ratios: peak height and/or peak area; full statistics: running mean; error warnings, built in self-test routines; control of flame autosampler Rank-Hilger Ltd., Atomspek Single 2 . 6 0.1 190-850 Digital HZ HCL Hewlett- 6-lamp turret; autozero and flame Westwood, H 1580 Packard ignition; curve correction; Ramsaate Road, calculator/ integration: programmable calculator M arg ate, Kent CT9 4JL, England printer output available ~~ S himadzu- AA-625 Single 1.9 Seisakusho Ltd., t 14-5 Uchikanda, 1-chome, Chiyoda-ku, AA-630 Single 1.9 Tokyo 101, Japan V.A. Howe & Co. Ltd., 88 Peterborough Road, London AA-640 Single 1.9 SW6 3EP, England (continued) * New equipment since publication of Volume 8 0.2 190-700 Meter or - - Quantitative flame emission; flameless digital capacity; flow lines for air, CZHZ and N2 0 0.2 190-900 Meter or - - Quantitative/qualitative flame digital emission; flameless capacity: flow line for air, Ar, C2H2, NzO, Hz; f!ame monitor, gas pressure monitor, wavelength drive 0.2 190-900 Meter or - Automatic background correction; emission: flameless capacity; flow lines for air, Ar, CZHZ, N20,.Hz; flame monitor, wavelength drive; integration digital quantitative and qualitative flame VI m t No up to date information suppliedTable 2.5C-COMMERCIALLY AVAILABLE ATO M!C ABSORPTION SPECTROMETERS- conliniicd Ln P Single/ Reciprocai Model doubre dispersion/ Resolution Wavelength Read Type Of Special features beam nm Der mn: /nm range/nm out background correction output Supplier (continued) AA-650 Double 1.9 0.2 190-900 Meter or - - digital Automatic background correction; quantitative and qualitative flame emission; built in peak catcher; flameless capacity: flow lines, for air; Ar, C2H2.N20, Hz; flame monitor; gas pressure monitor; wavelength drive; integration Vari an-Tec htr on Pty. Ltd., 679 Springvale Rd., Mulgrave; Vic. 3170. Australia Varian Associates Ltd., Instrument Group, 28 Manor Road, Walton on Thames, Surrey, England Varian Instrument Div., 611 Hansen Way, Palo Alto, CA 94303, U.S.A. AA-275 AA-475 AA-875* Single Double Double I EEE-488 RS-232-C 3.3 0.2 185-900 Digital DZ arc and parallel BCD 3.3 1 . 6 AA-575 Double 3.3 042 185-900 Digital DZ arc 0.05 185-900 Digital DZ arc 0-2 185-900 Digital DZ arc IEEE-488 RS-2 32-c and parallel BCD IEEE-488 and duplex RS-232-C IEEE-488 RS-232-C Parallel BCD Two-lamp turret overcoated reflective optics, automatic gas control system, compatible with samplers, printers, hydride and furnace atomization systems, Intel 8080 with 10 K ROM provides signal processing background correction, absorbance, conversion, integration, 3-standard curve-fitting, peak height and area measurement, lamp current control Two-lamp turret, overcoated reflective optics, automatic gas control system, compatible with samplers, printers, hydride and furnace atomization systems, Intel 8080 with 10 K ROM provides double-beaming background correction, absorbance conversion, integration, 3-standard curve-fitting, peak height and area measurement, lamp current control Computer compatible via two-way RS-232-C, for realtime signal generation and instrument control, new integrated, high sensitivity atomization 2 system.Four-lamp turret compatible with desktop computer, printer, samplers,, hydride and furnace atomization systems, Intel 8080 with 15 K ROM provides double beam background correction, absorbance ? h conversion, integration, 5-standard curve fitting, peak height and area measurement, statistics, self-test and 2 error detection Reflective optics with quartz overcoat; 2 fully microprocessor controlled three standard calibration optional automatic gas-control, +lamp turret 2 acquisition, comprehensive report Q 3AA-775 Double 1.6 0.05 185-900 Digital DX arc Reflective optics with quartz overcoat; fully microprocessor controlled five standard calibration with statistics and standard additions calibration; optional automatic gas-control, 4-lamp turret VEB Carl Zeiss Jena, 69 Jena, Carl-Zeiss Str. 1, German Democratic Republic Carl Zeiss Scientific Instruments Ltd., P.O. Box 43. 2 Elstree Way, Boreham Wood, Herts. WD6 lNH, England ~~~ ~ ~~~ - ~ AASl Single 1.5 - 190-820 Meter DX lamp 1OUmV 4-lamp turret: single or triple pass AASl N equipment) (600 ohms) for optics; autozero: titanium burner potentiometric heads; flow lines for air, C2H2, recorder or absorbance converter automatic flame ignition TECl printer or computer VIOTEC 1; signal output 775 mV (5 K ohms) for linear recording of absorbance N2O; gas pressure monitor, gas flow monitor; burner head safety interlock; (1520 New equipment since publication of Volume 8 t No up to date information suppliedVI Q\ Table 2.5D -COMMERCIALLY AVAILABLE ELECTROTHERMAL ATOMIZERS Special features Temperalure Ramp rale control range S upp I ier Model Type Control unit Baird Corporation* A3470 Graphite Rod programmable, dry ash - ( 2 stages) atomize: max.temp. 3500 "C Fits most AA spectrophotometers; air cooled, uses mains power, inert gas shielding; pyrolytic graphite coating for rods in siru; rapid interchange between flame and electrothermal methods Instrumentation 655' Laboratory 1nc.S 255' Graphite Programmable six stages, Furnace ramp or step from ambient, max.temp. 3500 " C Autosampler Digital timers for sample for flame 8 furnace operation calibrating the deposition, trigger circuitry for auto zeroing & auto spectrometer Perkin-Elmer HGA 400 Graphite Microprocessor unit Corporation$ furnace provides up to 8 steps of controlled heating; temp. ramp time, hold time, gas 8.other furnace and spectrophotometer control functions are programmed by direct keyboard entry; digital displays provide read-out of temp. time and prog. status Feedback from - tungsten temperature sensor True on temperature read-out: LED display; safety interlock system; automatic cell door: automatic cleaning; cell pressurization; convenient solid sampling capacity using micro boats Flame/furnace autosampling technique with auto calibration FASTAC, employs an aerosol deposition technique of introducing aerosol into furnace cuvette, which is at elevated temperature; sample volume, which evaporates on contact with graphite surface, is controlled by length of time sample is sprayed into furnace, allowing the operator to control sensitivity by varying deposition time 1 to 999 s From 2000 "C High .speed, temperature accessory per second to permits rapid heating to temperature 999 s between between 800 and 3000 "C for optimal any two temps.atomization; AS40 autosampler available for automatic insertion of up to 35 samples and blank and 35 standards into the HGA; will also perform automatic method of additions; automatic matrix modification: recalibration; automatic triggering of HGA and instrument read cycle for unattended operation P hot od iodeHGA 500 Graphite furnace Microprocessor unit provides up to 9 steps of controlled heating; temp., ramp time, gas and other furnace & spectrophoto- meter control functions are programmed for each step by direct keyboard entry; digital displays provide read-out of temp, time & programme status; up t o 6 complete programmes can be stored & recalled at the touch of 1 key Photodiode As for HGA 400 Furnace control programmes for up t o 6 different elements may be stored i n 6 programme memories; programme parameters for more than 6 elements can be stored on magnetic cards and recalled with the touch of one button; the optical temperature sensor and digital gas flow control for 2 different purge gases add to the versatility of the furnace programme; when used i n combination with the AS40 microcomputer furnace auto-sampler and the Model 5000 AA up to 35 samples, blank and three standards may be analysed for up to 6 elements, each without operator attention Bodenseewerk, HGA 500 Graphite Microcomputer controlled - - Fits Perkin-Elmer and Zeiss AA Perkin-Elmer & Co.furnace up to nine programme spectrophotometers; water-cooled; GmbH * inert gas shielding; safety features for failure of water, purge gas or tube break; ramp or stepwise increase of temperature plus isothermal phase i n each of the steps; recorder and peak reader control in each step preselectable; gas stop or miniflow, selectable temperature controlled maximum power heating for atomization steps for drying, ashing, sample pretreatment, atomize, tube clean, tube blank etc; max. temp. 3000 "C Pye Unicam Ltd.* SP 9-01 Graphite Programmable, dry, ash, Photodiode - Water-cooled, inert gas shielding, safety features for failure of water, tube life indicator and remote recorder control for 1,2,3 or all phases furnace atomize, tube clean, tube blank, with cancel and delay stages; max. temp. 3000 " C SP9 Video Furnace Graphite 6 phases each program- Photodiode 9 ramp rates Microcomputer control of all functions; furnace mable t o 3000 "C; linear 2-2000 "C s-1 video displays of set parameters and or non-linear temp. ramp on each phase; voltage or temp. control (no adj. t o photodiode sensor) status; storage of 10 furnace programmes; gas stop and recorder control on all phases; built in autosampler controls; fits all current Pye Unicam spectrophotometers SP9 Furnace Graphite furnace SP9 Furnace - Auto-sampler 4 phases each program- Photodiode 9 ramp rates Fits all current Pye Unicam mable to 3000 "C; voltage 2-2000 "C s-1 spectrophotometers or temp. control (no adj. of photodiode sensor) Automatic sampling of 38 - - Microprocessor control of all functions; samples and 2 wash positions selectable number of readings and volume for each sample cup identification, wash system interlock; automatic stop after last sample; fits all current Pye Unicam spectrop hotometers * New equipment since publication of Volume 8 t No up t o dale information supplied * Address as in Table 2.5CTable 2.5D-COMMERCIALLY AVAILABLE ELECTROTHERMAL ATOMIZERS- continued Speclal features Temperature Ramp rate conlrol range Model Type Control unit ul 00 * H1475 Graphite Programmable, dry, ash, No temperature - furnace wait, atomize; max. temp. control or 2600 "C variable ramping Watercooled, inert gas shielding Current stabilized to obtain - G FAZ Graphite Programmable, dry, ash, - atomize; max. temp. reproducible results 3000 "C furnace CRA 90 Graphite Programmable, dry, ash, - furnace atomize; max. temp. graphitetube) 3000 "C threaded raphite tube) graphite cup) 1 7 since publicatlon of Volume 8 25-800 "C s-1 Fits most AA spectrophotometers; water cooled; inert gas shielding and hydr en flame option; automatic rampTold atomization: pyrolytic graphite coating on cup and tubes b j No up to date information supplied 4 Address as in Table 2.5C b