Rapid multi-channel dilution analysis for simultaneous measurements

Rapid multi-channel dilution analysis (rMCDA) is an improvement upon the recently described multi-channel dilution analysis (MCDA) method, significantly enhancing the technique's sample throughput without sacrificing analytical accuracy or precision. rMCDA is based on the standard dilution analysis (SDA) method, correcting for both sample matrix effects and fluctuations in signal level over time like traditional standard additions and internal standard calibration, respectively. Dilutions of a standard are made autonomously as solution travels from an autosampler to an instrument through a manifold consisting of three tubing channels of varying lengths, all driven by the same peristaltic pump. The manifold is constructed so that a complete calibration consisting of a baseline sample measurement plus three additional standard levels can be collected in less than one minute of instrument runtime. rMCDA offers exceptional matrix effect correction, with analyte recoveries in difficult sample matrices such as 20% ethanol and 1% Ca ranging from 95 to 106%, with relative standard deviations on the order of 1%. rMCDA is validated by the analysis of three certified reference materials, with percent recoveries for a suite of analytes ranging from 91 to 104%, with relative standard deviations on the order of 1%.