On‐line SFC/FT‐IR analysis of agriculturally‐related compounds

Several agricultural compounds which are used as herbicide precursors have been analyzed by SFC and are detected on‐line via a flow cell FT‐IR interface. A mixture of ureas is separated on a microbore packed column; while a mixture of benzamides and anilides and a mixture of sulfonamides are separated on capillary columns. The use of 100% CO 2 as the mobile phase enables an infrared spectrum of each eluting analyte to be obtained on‐line with good signal to noise ratio. The urea mixture is also separated with a conventional cyanopropyl bonded phase analytical scale packed column using a methanol‐modified CO 2 mobile phase and UV detection. The separations achieved with and without modifier are compared.