Literature problem. Zinc is an essential micronutrient. It is estimated that 22 billon people are zinc deficient. B. J. Stevens et al. (Latin for “and others”) wrote a Technical Note (J. Anal. Atom. Spec. 2017, 32, 843, Open Access) describing a method for measuring zinc in blood plasma. Technical Notes are short descriptions of a novel apparatus or technique.
a. Only zinc is of interest in this study. Clinical samples contain from 0.60.6 to 1.6 ppb1.6 ppb zinc. It is desirable to use small volumes of sample. Use Figure 21-35 and Table 21-6 to predict the atomic spectrometric technique used.
b. Introductions provide background about the topic and previous work. What was the “gold standard” for determination of ZnZn in serum? Why was that technique not used in this study?
c. Methods and Materials is an alternative name for the “Experimental” section, where experimental conditions are detailed. How was glassware cleaned for trace analysis? How were vials checked for cleanliness?
d. Instrumental conditions may be detailed in the Experimental section or summarized in a table. What hollow-cathode lamp wavelength was used?
e. Was a linear or quadratic calibration used?
f. Results and Discussion describes the experimental results and their significance. Much of the discussion is about selection of the matrix modifier. What matrix modifier was used for quantitation of zinc in plasma?
g. How was the method validated?

Figure 21-35

Table 21-6

Objective of analysis Quantitative Qualitative/ Semi-quantitative Number of elements to analyze Few Many Many Concentration expected As low as ppb As low as 100's ppt As low as ppt As low as ppb As low as 100's ppt As low as sub-ppt % to ppm Atomic spectrometry technique Flame atomic absorbance Graphite furnace atomic absorbance Atomic fluorescence Microwave plasma-optical emission Inductively coupled plasma- optical emission Inductively coupled plasma- mass spectrometry X-ray fluorescence Laser-induced breakdown spectroscopy Laser ablation-inductively coupled plasma As low as ppb Harris/Lucy, Quantitative Chemical Analysis, 10e, 2020 W. H. Freeman and Company FIGURE 21-35 Guide to atomic spectrometry technique selection. ppt = parts per trillion. [Information from S. Elliott, "Comparison of ICP-QQQ and MP-AES to Alternative Atomic Spectrometry Techniques," Am. Lab. March 2017, p. 20.]