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Determination of low‐molecular‐weight amines and ammonium in saline waters by ion chromatography after their extraction by steam distillation
Author(s) -
Ferreira Fernanda Nunes,
Afonso Julio Carlos,
Pontes Fernanda Veronesi Marinho,
Carneiro Manuel Castro,
Neto Arnaldo Alcover,
Tristão Maria Luiza Bragança,
Monteiro Maria Inês Couto
Publication year - 2016
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201501387
Subject(s) - chemistry , chromatography , extraction (chemistry) , sodium , steam distillation , potassium , ion chromatography , ammonium hydroxide , potassium hydroxide , ammonium , sodium hydroxide , analyte , distillation , matrix (chemical analysis) , detection limit , inorganic chemistry , organic chemistry
A new method was developed for the determination of ammonium ion, monomethylamine and monoethylamine in saline waters by ion chromatography. Steam distillation was used to eliminate matrix interferences. Variables such as distillation time, concentration of sodium hydroxide solution and analyte mass were optimized by using a full two‐level factorial (2 3 ) design. The influence of steam distillation on the analytical curves prepared in different matrices was also investigated. Limits of detection of 0.03, 0.05 and 0.05 mg/L were obtained for ammoniumion, monomethylamine and monoethylamine, respectively. Saline water samples from the Brazilian oil industry, containing sodium and potassium concentrations between 2.0–5.2% w/v and 96–928 mg/L, respectively, were analyzed. Satisfactory recoveries (90–105%) of the analytes were obtained for all spiked samples, and the precision was ≤ 7% ( n = 3). The proposed method is adequate for analyzing saline waters containing sodium to ammoniumion, monomethylamine and monoethylamine concentration ratios up to 28 000:1 and potassium to ammonium, monomethylamine and monoethylamine concentration ratios up to 12 000:1.