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omization rate. The furnace atmo­sphere also heats quickly, enhancing the decomposition of gas-phase mole­cules. The result is slightly increased sensitivity and a drastic reduction in both matrix interferences and back­ground absorption problems. In fact, the authors say that there is no need for background or slope corrections except in high-solid-content samples such as seawater. A potential disad­vantage of capacitive heating is the need for extremely fast electronics to accurately record the signals.

Holcombe and Salmon (28) have described an instrument that gives both time (1 ms) and space (0.3 mm) resolution of absorbances within a 3-mm diameter furnace. The system is being used to study the effects of va­porization, desorption, oxidation, etc. on atom populations and the detailed distribution within the atomizer. Hol-combe's studies represent the "de­tailed studies of principle and mecha­nisms" to which Laitinen referred. They are more likely to have an im­pact on the design of the next genera­tion of furnaces than to dramatically change the way people use the present ones.

Simultaneous multielement analy­sis, which is so common in emission spectroscopy, has not been significant­ly employed in atomic absorption. This may change based on work by Harnley et al. (29). They use a contin­uum source, a multichannel high-reso­lution échelle spectrometer, and wave­length modulation to get background-corrected absorption data for 16 ele­ments. Detection limits are compara­ble to conventional AA at wavelengths greater than about 280 nm. There is a gradual deterioration toward shorter wavelengths, with zinc (214 nm) being about an order of magnitude poorer than with a hollow cathode lamp source. The linear range is also limited with their system because the effective bandpass is about the same as the line width—not much narrower, as re­quired in the simple equations that predict linearity. They have developed a novel method of automatically shift­ing the wavelength of measurement to the wings of the line when high ab­sorbances are encountered. In this way, the measured absorbance can be kept low enough to be in the linear range, even at relatively high analyte concentrations. The system seems ripe for commercial development, because it provides high-quality background correction plus multielement capa­bility.

In most laboratories furnaces are used exclusively for atomic absorp­tion, but Ottaway and co-workers (30) have demonstrated that the furnace atmosphere is hot enough to excite useful emission from some of the more

1522 A · ANALYTICAL CHEMISTRY, VOL. 54, NO. 14, DECEMBER 1982

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