Application of Turbulent Flow Chromatography Load Columns for the On-Line Analysis of Anti-Infectives in Wastewaters

Simultaneous determination of sulfonamides and fluoroquinolones from environmental water based on magnetic double-template molecularly imprinting technique

In this work, a fast and selective method based on magnetic extraction is presented for the simultaneous extraction of sulfonamides (SAs) and fluoroquinolones (FQs), followed by liquid chromatography-tandem mass spectrometry detection. In this method, magnetic surface double-template molecularly imprinted polymers (MSdt-MIPs) with superparamagnetic property and high selectivity toward both SAs and FQs were synthesized and directly applied to the simultaneous extraction of SAs and FQs from environmental water as magnetic adsorbents. The extraction and enrichment procedures could be accomplished in one single step by stirring the mixture of MSdt-MIPs and water sample, and the MSdt-MIPs with adsorbed analytes were easily separated from the water sample by a magnet afterwards. The adsorption mechanism of MSdt-MIPs was investigated by employing the adsorption thermodynamic and kinetic studies, and the selectivity of the MSdt-MIPs toward target analytes was evaluated through the selectivity test. For validation of the proposed method, the matrix effect was evaluated and compared to that of the traditional SPE method. Excellent linearity (R > 0.9990) for both SAs and FQs were obtained in the concentration range of 20-2000 ng L^-1, and the limits of detection are in the range of 3.0-4.7 ng L^-1 for SAs while 4.1-6.1 ng L^-1 for FQs. Finally, the proposed method was successfully applied to the simultaneous determination of SAs and FQs in several environmental water samples.

Recent approaches for on-line analysis of residues and contaminants in food matrices: A review

This review highlights recent developments for on-line determination of residues and contaminants in complex matrices such as food samples. This involves the on-line coupling of a sample preparation technique (as the first "dimension") with a chromatographic system (second "dimension"), usually followed by mass spectrometry. Although frequently treated as quite distinct techniques, the role of all devices utilized as the first dimension in this approach aims to decrease the sample complexity while eliminating as much as possible the matrix contaminants to facilitate the qualitative and quantitative determination of the compounds of interest. This review will focus on the following techniques as the first dimension: (i) on-line solid-phase extraction; (ii) in-tube solid-phase microextraction; (iii) matrix solid-phase dispersion; and (iv) turbulent flow chromatography. The second dimension is usually performed using a chromatographic column to isolate the analyte(s) of interest for further mass spectrometry determination. A description of the basis of this on-line approach and its distinct set up possibilities is presented, which is followed by a critical review of the literature covering this subject in the last ten years (focusing on the last five years) with emphasis on the analysis of residue and contaminants in food samples.

Quantification of carbamazepine and atrazine and screening of suspect organic contaminants in surface and drinking waters

A new approach for the identification of suspect trace organic contaminants in drinking and surface waters is presented. Samples were initially analyzed using a target determination method for two contamination tracers, carbamazepine (CBZ) and atrazine (ATZ). This method used offline solid-phase extraction and online solid-phase extraction techniques coupled to liquid chromatography-triple quadrupole mass spectrometry to accelerate the sample preparation process and improve method performance. CBZ and ATZ were found respectively in 31% and 56% of the samples, and concentrations were usually <20 ng L(-1). These samples were re-analyzed with a similar method on a quadrupole time-of-flight mass spectrometer to identify suspect contaminants by means of exact mass measurements and isotope patterns. A database of 264 common organic contaminants was built and used in conjunction with a Molecular Feature algorithm to identify the presence of these substances in drinking and surface water collected from different sources at various locations across Canada. Several organic contaminants were identified in the samples, but only the presence of caffeine, desethylatrazine, simazine and venlafaxine could be verified by comparison to pure standards. The presence of desethylatrazine was also confirmed by MS/MS experiments. These results suggest that target analysis for tracers of organic contamination may be a helpful tool to prioritize samples which should be further screened for suspect contaminants. This study also shows that the combination of separation techniques (offline and online SPE, LC) contribute to advance the applicability of high-resolution mass spectrometry for the identification of trace organic contaminants by accelerating the preparation step, reducing complexity and increasing analyte concentrations for optimal detection.