PRS Technology

Since the PRS® Probes attract and adsorb ions through electrostatic attraction, all ionic species (i.e., nutrient or toxin) can be adsorbed and measured analytically. The analytical instrument (i.e., colourimetry, ICP, AA, FES, HPLC, etc.) used to measure the analyte concentration will depend on the ion of interest.

Western Ag Innovations has always used the same basic methods for measuring nutrients adsorbed on PRS® Probes.  All PRS® Probes in a sample are transferred to Ziploc® bags and 17.5 mL of 0.5 mol/L HCl is added per probe.  Probes are eluted for one hour.  Inorganic N (ammonium and nitrate) in the eluant is then determined colorimetrically using automated flow injection analysis: the SK lab currently uses a Skalar San++ Analyzer (Skalar Inc., Netherlands) while the ID lab uses a FIAlyzer (FIAlab Inc, USA).  The remaining elements (P, K, S, Ca, Mg, Al, Fe, Mn, Cu, Zn, B, Al, Pb, and Cd) are measured using inductively coupled plasma optical emission spectrometry (ICP-OES): the SK lab uses a SpectroGreen analyzer (SPECTRO Analytical Instruments Inc., USA) and the ID lab uses an Optima ICP-OES 8300 analyzer (PerkinElmer Inc., USA).  All standards and controls are prepared in a 0.5 mol/L HCl matrix equivalent to that of the samples.

High-pressure liquid chromatography can be used to measure herbicide and glucosinolate contents in the PRS® probe eluate (Szmigielska and Schoenau, 2000; Szmigielska et al.,2000; Szmigielska and Schoenau, 1999; Szmigielska et al., 1998; Szmigielska and Schoenau, 1995).