Optimization of instrumental parameters in flameless atomic absorption spectrometry

Abstract

Fundamental aspects of various noise sources in flameless atomic absorption have been considered and the measurement system appeared to be shot noise limited. The influence of time constants of the measurement system, modulation frequency of the primary source, and heating rate of the sample cell on both noise level and signal-to-noise ratio have been experimentally investigated. Furthermore, the effect of the bandwidth of the amplifier-recorder system on analytical parameters, such as detection limit, sensitivity, and linear working range of the calibration curves, has been studied. Detection limits for undistorted signals, optimum signal-to-noise ratio, and highly distorted signals are reported.

Background reduction during direct atomization of solid biological samples in atomic absorption spectrometry

“…Although this low char temperature appears to cause little charring except dehydration reactions, it has been used successfully to determine zinc with closed crucibles; 97 to 116% recovery from 3 to 9 mg of orchard leaves was obtained. Note that the above char temperatures are 200 to 300 K less than ash temperatures recommended for lead or cadmium in other atomizers (6,7). About half of the difference may be attributable to the effectiveness of batch charring in air.…”

“…One approach which can meet these requirements is atomic absorption analysis, since the technique is highly sensitive and yet very few elements interfere. An atomic absorption procedure for technetium was developed by Hareland et al (6). It involves use of the acetylene-air flame and yields a sensitivity of 3 gg/mL of sample solution.…”

“…For analytical purposes, it is important to note that the transient peak terminates at essentially the same time (t = 3 s) regardless of how large the sample weight. Element peaks for samples or standards are observed at a later time, as in Figure 4e and f, suggesting the possibility of time-resolved analyses (6) for samples over 8 mg.…”

“…Standard additions are often used (4). Specific interferents might be removed by pretreatments, such as matrix modification with NH4N03 (5) or improved use of the char cycle with air or hydrogen atmospheres (6,7).…”

Effect of heating rates in graphite furnace atomic absorption spectrometry

“…In recent years, models for temporal signal profiles obtained using various types of electrothermal atomizers have been proposed (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). The instrumental parameters that affect the absorption signals obtained with various atomizers have been studied also (9)(10)(11).…”