An instrument for multielement flame emission analysis is described which consists of a 0.5-m Ebert monochromator, a silicon diode vidicon tube, and an optical multichannel analyzer. Optical and electronic considerations of the system are discussed. Using this system, a spectral "window" of 20 nm is monitored simultaneously and atomic lines 1.4 A apart are resolvable. Detection limits, obtained under compromise flame conditions, are presented for Mo, Fe, Ca, Al, Ti, W, Mn, and K using spectral lines present in a single window. The multielement analysis of a geological standard rock sample for Fe, Ca, Al, and Ti is described, and the results are compared with the accepted valiles. Other potential windows for multielement analysis are presented.

Table 111. Relative sensitivities are compared for lead, bismuth, selenium, thallium, and tellurium when alone and in the presence of nickel, a nickel-base alloy, an iron-base alloy, or a cobalt-base alloy. The magnitudes of the interferences were greatest for selenium, where a cobalt alloy matrix enhanced the selenium signal by a factor of two. It is interesting to note that there was not a large difference in sensitivity for any of the elements in nickel or in a nickel alloy. For most precise work, standards must be similar in composition to the samples.Purge Gas Flow Rate. The flow rate of argon through the graphite tube was not critical. In the cases of lead, thallium, and tellurium, significant improvements in detection limits were obtained when the purge gas flow was interrupted for a short time during the char cycle.Spectral Band-Pass. The effects of spectral band-pass on signal-to-background ratios were measured for each of the five analyte elements. The effects were negligible except in the case of bismuth, where a smaller band-pass partially resolved the 223.1-and 222.8-nm lines and improved the signal-to-background ratio by less than a factor of two. Comparative Results. The four nickel-base reference alloys described previously were analyzed by the graphite furnace-atomic absorption procedure. Table IV lists a comparison of the values obtained by this technique with values obtained by other methods. The precision of the method was evaluated by analyzing ten separately weighed portions of a nickel-base alloy. The results, based on single absorbance measurements, are tabulated in Table V.The rapid simultaneous determination of sodium, potassium, and calcium in blood serum is described using a recently developed vidicon flame spectrometer. The system, which includes a silicon-intensified target vidicon tube, monitors a 40-nm spectral window. The simultaneous analysis is accomplished by direct injection of 200 pI of serum into a nitrous oxide-acetylene flame, and multichannel monitoring of the spectral region 807 nm to 847 nm. Results for control serum and clinical samples indicate an accuracy and precision of better than 2 % .

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The viscosity of solutions (6% wiw protein in 45% sucrose) of porcine and bovine whole blood plasma, porcine serum and porcine plasma fractions exhibited Newtonian behaviour between 20°C and 73°C. On further heating, the viscosity of these solutions increased exponentially producing a reversible gel structure at 76°C and an irreversible gel at 79°C. In contrast, egg albumen protein solutions indicated a relatively low initial viscosity but started to thicken at 65"C, forming reversible gels at 73°C and irreversible gels at 76°C. The viscosity of the egg albumen protein solutions was similar to that of the serum proteins and plasma protein fractions and less than that of whole plasma protein solutions. Viscosities lower than expected were exhibited by mixtures of whole porcine or bovine plasma and egg albumen proteins. However, synergistic interaction between the proteins of egg albumen and porcine plasma fraction I and fraction 111 (albumin) and porcine serum occurred at high temperatures of heating.