Determination of phenoxy herbicides in water samples using phase transfer microextraction with simultaneous derivatization followed by GC-MS analysis

• Published in: Journal of separation science 2012-12, Vol.35 (23), p.3381-3388
• Main Authors: Nuhu, Abdulmumin A., Basheer, Chanbasha, Alhooshani, Khalid, Al-Arfaj, Abdul Rahman
• Format: Article
• Language: English
• Subjects: Acetic acid; Analysis methods; Analytical chemistry; Applied sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Correlation; Derivatization; Drinking water and swimming-pool water. Desalination; Exact sciences and technology; Fresh Water - chemistry; Gas chromatographic methods; Gas Chromatography-Mass Spectrometry - methods; Herbicides; Herbicides - analysis; Herbicides - isolation & purification; Liquid Phase Microextraction - methods; Mass spectrometry; Mathematical models; Natural water pollution; Phase transfer catalyst; Phase transfer catalysts; Phase transfer microextraction; Phenoxy herbicide; Pollution; Propanoic acid; Sea water; Seawater - chemistry; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - isolation & purification; Water treatment and pollution
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.201200218

A sensitive and accurate method for the determination of two model phenoxy herbicides, 4‐chloro‐2‐methylphenoxy acetic acid and 4‐chloro‐2‐methylphenoxy propanoic acid, in water is explained. This method utilizes a simple phase transfer catalyst‐assisted microextraction with simultaneous derivatization. Factors affecting the performance of this method including pH of the aqueous matrix, temperature, extraction duration, type and amount of derivatization reagents, and type and amount of the phase transfer catalyst are examined. Derivatization and the use of phase transfer catalyst have proven to be especially vital for the resolution of the analytes and their sensitive determination, with an enrichment factor of 288‐fold for catalyzed over noncatalyzed procedure. Good linearity ranging from 0.1 to 80 μg L−1 with correlation of determination (r2) between 0.9890 and 0.9945 were obtained. Previous reported detection limits are compared with our new current method. The low LOD for the two analytes (0.80 ng L−1 for 4‐chloro‐2‐methylphenoxy propanoic acid and 3.04 ng L−1 for 4‐chloro‐2‐methylphenoxy acetic acid) allow for the determination of low concentrations of these analytes in real samples. The absence of matrix effect was confirmed through relative recovery calculations. Application of the method to seawater and tap water samples was tested, but only 4‐chloro‐2‐methylphenoxy propanoic acid at concentrations between 0.27 ± 0.01 and 0.84 ± 0.06 μg L−1 was detected in seawater samples.