In the case of the proposed HR-CS FAAS method, the measurements
of N and P using the molecular lines of NO at 215.360 nm and of PO at
247.620 nm, respectively, and detection of K used the alternative atomic
line for K at 404.722 nm. Seven replicate measurements were made at
observation heights of 9 mm (NO, PO) and 8 mm (K), using an aspiration
rate of 5.0 mL min−1.
In HR-CS FAAS, it is possible to adjust the sensitivity using
wavelength-selected absorbance (WSA) [15], employing part of the
line wings as well as the core. The influence of WSA on sensitivity, linear
correlation coefficient (r), characteristic concentration (Co), limit of detection (LOD), and precision (RSD%) was evaluated by varying the pixel-number from 1 to 9. After optimization, WSA equivalent to 5 pixels for NO and PO, and 1 pixel for K, were used throughout the work.