Sensitive in-surface infrared monitoring coupled to stir membrane extraction for the selective determination of total hydrocarbon index in waters

摘要: In this paper, the direct coupling between stir membrane extraction and infrared spectroscopy working under transmission mode is presented for sensitive selective determination of total hydrocarbon index in waters. For purpose, a new unit was built using stainless steel order to maximize adsorption target analytes 40-μm-thick polytetrafluoroethylene membrane. The method allows hydrocarbons presence grease, hexadecane stearic acid as model compounds, respectively. proposal optimized depth, taking into account main experimental variables such thickness, time, stirring sample volume. Later on, characterized on basis its linearity, precision, limits detection. combination with limit detection 18 μg L−1, precision being (expressed relative standard deviation) better than 4.3%. analytical provides high throughput since some extractions can be performed parallel, deviation devices 8%. proposed finally compared terms figures counterpart ASTM method, recently presented.