DETERMINATION OF NITRATE IN SUSPENDED PARTICULATE MATTER BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH UV DETECTION

For the determination of nitrate in suspended particulate matter (s.p.m.), high-performance liquid chromatography (h.p.l.c.) with a u.v. detector at 210 mm gives precise and accurate results. Chloride, bromate, iodide, nitrite, thiocyanate and various cations do not interfere. Calibration graphs are linear over the range 0-20 ppm of nitrat-enitrogen, and the limit of detection is 0.25 ng of nitrate-nitrogen. The coefficients of variation at 5.0- and 10.0-ppm levels are 3.4 and 2.9%, respectively. Results obtained by the h.p.l.c. method and by two 2,4-xylenol spectrophotometric methods for aqueous extracts of s.p.m. are compared. Agreement is generally good, particularly when choride is removed in the 2,4-xylenol method, but the spectrophotometric methods are much more prone to interference. © 1979.