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

Abstract

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 (r(2) ) 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.

Bioactive Micronutrients in Coffee: Recent Analytical Approaches for Characterization and Quantification

“…In one example, caffeine was extracted from water into dichloromethane, while CGA remained in the residual aqueous solution [105]. To solubilize a polar analyte in an organic solvent during an LLE procedure, especially when gas chromatographic analysis is intended, it is sometimes necessary to add ionic surfactants in the extraction medium [106, 107]. …”

Development and validation of kinetic spectrophotometric method for herbicide bromfenoxim determination

“…Liquid chromatography (LC) (Rosales-Conrado et al, 2005;(Chen et al, 2006;Lui et al, 2007) and capillary electrophoresis (CE) (Fu et al, 2009;Li and Cai, 2008;Li et al, 2009;Wen et al, 2012) have been widely used for separation and determination of phenoxy herbicides. Phenoxy herbicides have been determined by GC-MS after microextraction (Nuhu et al, 2012), and by LC/MS/MS (Santilio et al, 2009). Karlhuber et al, (1975) determined the bromofenoxim in hops by GC with mass fragmentation.…”

Rapid and sensitive detection of the phenoxy acid herbicides in environmental water samples by magnetic solid‐phase extraction combined with liquid chromatography–tandem mass spectrometry

“…At present, there have been many reports for the analysis of phenoxy acid herbicides in environmental water samples , vegetables and fruits , soil , and other food by GC with electron capture detector or MS, HPLC methods with UV or MS detectors, and CE. Phenoxy acid herbicides with high polarity are not easily vaporized before they could be analyzed by GC.…”

“…Phenoxy acid herbicides with high polarity are not easily vaporized before they could be analyzed by GC. Therefore, a derivatization step must be needed before GC analysis, making the analysis process complex and time consuming . CE and HPLC–UV are not very sensitive and selective for the trace analysis.…”