title: Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography.
abstract: An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used in this study. Under the experimental conditions, the UV peaks of salicylic acid and 2,3-dihydroxybenzoic acid were well separated from the peaks of humic acid in the chromatogram. Concentrations of the two small organic acids could be accurately determined from their peak areas. The concentration of humic acid in the mixture could then be derived from mass balance calculations. The measured results agreed well with the nominal concentrations. The detection limits are 0.05 mg/L and 0.01 mg/L for salicylic acid and 2,3-dihydroxybenzoic acid, respectively. Applicability of the method to natural samples was tested using groundwater, glacier, and river water samples (both original and spiked with salicylic acid and 2,3-dihydroxybenzoic acid) with a total organic carbon concentration ranging from 2.1 to 179.5 mg C/L. The results obtained are promising, especially for groundwater samples and river water samples with a total organic carbon concentration below 9 mg C/L.
authors.affiliation: Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, PR China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Qin
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.forename: Guangcai
authors.initials: G
authors.lastname: Wang
authors.forename: Liping
authors.initials: L
authors.lastname: Weng
mesh_terms: D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006812:Humic Substances / Q000032:analysis*; D062385:Hydroxybenzoates / Q000032:analysis*; D057230:Limit of Detection; D020156:Salicylic Acid / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D006812:Humic Substances; D062385:Hydroxybenzoates; C009135:2,3-dihydroxybenzoic acid; D020156:Salicylic Acid