Bulk acoustic wave sensor for non-suppressed ion chromatographic determination of nitrate and other inorganic anions in vegetables

A new type of bulk acoustic wave sensing device based on a conductivity bulk acoustic wave frequency response is applied in ion chromatography to determine nitrate and other inorganic ions in vegetables. The present method has the advantages in its rapidity, simplicity, sensitivity and accuracy. Detection limits (peak=3 sigma) are obtained for NO3-, Cl-, NO2-, H2PO4- and SO42- at concentrations of 1, 0.6, 1, 7 and 3 ng (on column), respectively. Neither derivatization nor a clean-up step is necessary besides filtration. For the IC analysis, the analytical column is a Shim-pack IC A1 column, and the eluent is 2.0 mM phthalic acid solution with pH 4.0. A comparison of IC-SBAW with conventional IC is made. The method allows the simultaneous determination of nitrate and other inorganic ion levels in vegetables.