QUANTITATIVE MEASUREMENTS IN CONTINUOUS-FLOW HPLC NMR/

Two methods for the quantitative determination of compounds in continu ous-now HPLC/NMR are described, The first method uses an internal stan dard (caffeine) of known concentration directly mixed into the mobile phase, while with the second method, a known amount of internal standa rd is injected onto the column during the chromatographic run. The lat ter method was validated using several nitroaromatic compounds and exp losives, Deviations between the injected and calculated amounts of ana lytes are usually below 10% while the relative standard deviation rang es from 2% in the upper microgram range to 40% at the limit of detecti on.