Methods for colorimetric endpoint detection and multiple analyte titration systems

An automated titration system comprising

• a reaction manifold comprising a conditioning manifold and a second liquid mixer, the reaction manifold in fluid communication with the sample source and the titrant source for mixing a continuously flowing and refreshed sample stream containing an unknown concentration of a first analyte with a first titrant and an unknown concentration of a second analyte with a second titrant;
• a sample pump in fluid communication with a source of the sample and the reaction manifold continuously pumping the sample stream from the source of the sample into the reaction manifold through a sample stream inlet;
• a first titrant pump in fluid communication with a source of the first titrant and the reaction manifold for pumping the first titrant into the reaction manifold through a first titrant inlet to contact the continuously flowing and refreshed sample stream;
• a second titrant pump in fluid communication with a source of the second titrant and the reaction manifold for pumping the second titrant into the reaction manifold through a second titrant inlet to contact the continuously flowing and refreshed sample stream;
• a multi-wavelength detector in fluid communication with the reaction manifold for detecting a first titration endpoint of the reaction between the first analyte and the first titrant and for detecting a second titration endpoint of the reaction between the second analyte and the second titrant, wherein the detector is downstream form the first and second titrant inlets and a defined distance from the first and second titrant inlets;
• and
• a controller communicatively coupled to the sample pump, the first titrant pump, the second titrant pump, and the detector,
• wherein the conditioning manifold comprises a first liquid mixer and the conditioning manifold is downstream from the sample stream inlet, the first titrant inlet and the second titrant inlet are downstream from the conditioning manifold and upstream from the second liquid mixer, and the second liquid mixer is upstream from the detector,
• wherein the controller controls the sample pump to set a continuous flow rate of the sample stream, controls the first titrant pump to set a continuous flow rate of the first titrant, controls the second titrant pump to set a continuous flow rate of the second titrant, and receives data from the detector to detect the first titration endpoint for the reaction between the first analyte and the first titrant and determine the first analyte concentration at the first titration endpoint and to detect the second titration endpoint for the reaction between the second analyte and the second titrant and determine the second analyte concentration at the second titration endpoint.