Nitrogen (N), phosphorus (P), and potassium (K) are the major essential
nutrients of plants and the main constituents of fertilizers. The
NPK rating (usually written as N–P
2
O
5
–K
2
Spectrochimica Acta Part B 101 (2014) 240–244
O) of fertilizers is normally
assessed using spectrophotometry [1] or Kjeldahl analysis [2] for N,
spectrophotometry [3] or gravimetry [4] for P, and atomic emission
spectrometry for K [5]. Large-scale routine analyses of NPK fertilizers
could therefore be substantially simplified if only a single technique
was used. In this context, high-resolution continuum source atomic
absorption spectrometry (HR-CS AAS) [6] offers a simple, robust, and
relatively low cost technique for the efficient determination of N, P,
and K. Special features of the method are the ability to make molecular
absorption measurements and the availability of alternative lines to
adjust the required sensitivity.