Optimization of method for detecting and characterizing NOM by HPLC-size exclusion chromatography with UV and on-line DOC detection.

High-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) with ultraviolet absorbance (UVA) and on-line dissolved organic carbon (DOC) detectors has been adapted and optimized under various conditions. An enhanced HPSEC-UVA system employing a modified commercially available DOC detector provides a better understanding of the qualitative and quantitative natural organic matter (NOM) properties in water samples by detecting aromatic and nonaromatic fractions of NOM as a function of molecular weight (MW). The most critical merit of this system is that the DOC detector is readily available and widely used. With only a few modifications, a commercially available TOC analyzer served as a DOC detector, integrated with the HPSEC to measure DOC along with UVA, and provided a specific UVA (SUVA) chromatograph that is useful information for drinking water plant design and operation. Without preconcentration, samples can be analyzed with a small amount of sample, with a DOC detection limit as low as 0.1 mg/L (as DOC).