a top view of the cell with such ribs the length of the ribs is determined by a minimum inner diameter x and the maximum outer diameter y the maximum outer diameter y is determined by the cell outer diameter d and the minimum cell wall thickness z in the preferred embodiment the minimum inner diameter is determined by the probe diameter and the stirring radius of the sample probe in the analyzer the rib thickness t and the rib spacing s can be varied to increase or decrease the amount of surface area in the cell by increasing the surface area of the cell the reaction can be moved from the inline source to a reaction in the cell one advantage is that the reaction time can now be controlled by how long the sample is left in the cell using an inline source the reaction time is controlled by trying to control the flow rate an d length of travel through the inline source in another example embodiment the cell geometry has been changed by adding a screw thread feature to the inside of the cell fig5 is a side view of such a cell the thread depth is determined by the maximum outer diameter the thread inner diameter is determined by the probe diameter and the stirring radius of the sample probe in the analyzer the pitch of the thread may be varied to increase or decrease the amount of surface area provided by the cell the screw thread may be any type of thread for example square.