Abstract: An apparatus and method for interfacing a capillary with a detector is disclosed. In particular, a capillary that is used in a capillary electrophoresis technique is interfaced with an off-column detector that is destructive of the sample or that will otherwise create adverse affects on the operations of the capillary electrophoresis. By way of example only, a nitrogen chemiluminescent detector using pyro-chemiluminescent techniques is discussed. An interface between the separation and detection systems is essential to prevent interference between the two systems. The interface apparatus and method are achieved by creating a closed connection between the two systems within which the pressure and sample flow rate can be controlled. Pressure control is achieved through the introduction and venting of gas into and from the integrated system. Interference between interfaced systems is then prevented by equalizing the pressure in the interface apparatus with the head pressure on the inlet end of the capillary.

Abstract: A method for analyzing total bound nitrogen in a sample and providing an output data of total bound nitrogen and constituent compounds (nitrate and nitrite) is disclosed. The total nitrogen bound method provides a discrete sample through a furnace in the presence of continuous flow of water as carrier as well as oxygen carrier gas, resulting in the oxidation of the nitrogen compounds to nitric oxide. The nitrate method involves a discrete sample with water as a carrier provided to a sparge tank. The nitrite is catalytically reduced to nitric oxide in the presence of tartaric acid and ascorbic acid. The nitrate method involves a first conversion to change the nitrate to a nitrite. The first conversion occurs in the presence of a copper-cadmium catalyst causing the formation of the NO.sub.2. The nitrile is subsequently converted into NO. The nitric oxide produced in each of the three methods is measured in a chemiluminescent nitrogen detector.