Performance characteristics of a continuum-source wavelength-modulated atomic absorption spectrometer

Precision of wavelength-modulated atomic absorption measurements of high calcium concentrations in a nitrous oxide-acetylene flame

“…Instrumentation. The WM-AAC spectrometer, previously described in detail (16), consisted of a 300-W Cermax prefocused xenon arc lamp, a single-channel echelle monochromator modified for wavelength modulation, and analog signal processing electronics. The Cermax lamp was operated at 20 A.…”

“…Calibration curves were plotted on logarithmic coordinates. The detection limits for calcium (SNR = 3 using 5-s integration time) in the nitrous oxide-acetylene flame for WM-AAC and AAL are 0.008 and 0.003 mg/L, respectively (16). Measurements by AAL were performed only up to 100 mg/L because intense analyte flame emission from the 300 mg/L calcium solution saturated the photomultiplier tube (PMT).…”

Determination of phosphorus in copper-based alloys using ion-exchange chromatography and direct-current plasma emission spectrometry

“…The output from both chromatographic systems flowed directly into the DCP nebulizer, bypassing the DCP peristaltic pump, which was still used to drain the mixing chamber. The wavelength-modulated echelle spectrometer and detection electronics have been described previously (7). Entrance and exit slit widths of 200 µ were used to obtain the optimum signalto-noise ratio (SNR).…”

“…The zero-crossing method is not sensitive to flicker in the intensity of the interferent line but does require a stable shape of the interferent response function (i.e., the spectral line shape). The DCP has been shown to exhibit "self-reversal noise" (7), which is a flicker noise caused by variations in the concentration of absorbing species in the cool region of the DCP between the spectrometer and the excitation zone. Such a noise would destabilize the interfering element line shape (and thus the response function) from the DCP and would result in a fluctuation of the zero-crossing.…”

Continuum source atomic absorption spectrometry and detector technology: A historical perspective

“…In 1977, a device was developed by Harnly [68] for simultaneously extraction of both the varying quantity (I 0 − I) and the corresponding value of I 0 from the PMT signal, and for the analogue calculation of the absorbance value log(I 0 / I). Thirty-two elements were investigated in order to determine the analytical performance of an instrument equipped with this device [69]. LODs were found to be about 4 times better for λ N 250 nm and up to 20 times poorer for λ b 250 nm, as compared to LS AAS.…”