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Efficiency of Hexane Extraction of Napropamide from Aldrich Humic Acid and Soil Solutions
Author(s) -
Williams C. F.,
Letey J.,
Farmer W. J.,
Nelson S. D.,
Anderson M.,
BenHur M.
Publication year - 1999
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1999.00472425002800060009x
Subject(s) - extraction (chemistry) , dissolved organic carbon , chemistry , humic acid , organic matter , hexane , environmental chemistry , soil water , chromatography , soil science , environmental science , organic chemistry , fertilizer
Dissolved organic matter (DOM) has been shown to form a stable complex with Napropamide [2( α ‐naphthoxy)‐ N,N ‐diethyl propionamide] and to facilitate its transport through soil columns. Liquid‐liquid extraction of organics is a common method to transfer napropamide from water into an organic phase for gas chromatography analysis. A study was conducted to determine the effect of Aldrich humic acid, soil‐derived dissolved organic matter, electrical conductivity, and hydrogen ion activity on the ability of hexane to extract napropamide from solutions and from soil extracts. The electrical conductivity of Aldrich humic acid solutions (0.0, 48, and 100 mg C L −1 ) were adjusted to 0.01, 0.97, and 1.69 dS m −1 by adding NaCl and CaCl 2 , and pH (8.2, 7.4, and 5.6) was adjusted using HCl and NaOH. Electrical conductivity had no effect on extraction efficiency. In the absence of DOM pH had no effect on extraction efficiency. Extraction efficiency decreased with increasing DOM concentration. Maximum reduction in extraction efficiency occurred in the presence of DOM when solution pH was near neutrality. A maximum extraction efficiency of 100% was observed in the absence of DOM and a minimum of 68% when napropamide was added to DOM solutions at pH 8.2 and then lowered to pH 5.6. Management practices such as liming and allowing napropamide to dry on the soil may increase environmental transport. Also quantification of napropamide in environmental samples can be affected by DOM.