Faster and simpler determination of chlorophenols in water by fiber introduction mass spectrometry

Rapid quantification of 2,4-dichlorophenol in river water samples using molecularly imprinted polymers coupled to ambient plasma mass spectrometry

Rapid quantification of environmental pollutants is important for water quality control and environmental monitoring. In this work, we report the development of molecularly imprinted polymers (MIPs) obtained from poly(methyl vinyl ether-alt-maleic acid) polymer. The synthesized materials were used for selective preconcentration of 2,4-dichlorophenol, a priority pollutant which creates a threat to public health. The structure of poly(methyl vinyl ether-alt-maleic acid) was functionalized with 4-aminomethylpyridine (4-AMP) to incorporate pyridine groups presumably responsible for increased affinity towards 2,4-dichlorophenol. The synthesis was performed with different degree (10%, 20% and 30%) of 4-AMP functionalization to investigate the influence of pyridine group content on the final MIPs properties. The molecular imprinting process was conducted by amidation of polymers' anhydride groups with diethylenetriamine. Moreover, the experimental data indicated that maximum adsorption capacity was observed for the highest 4-AMP functionalization degree. Similarly, MIPs with the highest 4-AMP content proved to possess the highest selectivity towards the analyte. Finally, the functionalized MIPs were used to quantify 2,4-dichlorophenol by their direct introduction into a specially designed ambient mass spectrometry setup. The detection limits were improved significantly over the ones measured for pure analyte solution. The proposed analytical technique was used to quantify 2,4-dichlorophenol in river water and wastewater samples. Good recovery results were obtained, which proves that the method can be used for analysis of complex real-life samples.

Direct Coupling of SPME to Mass Spectrometry

Solid-phase microextraction devices are normally analyzed by gas or liquid chromatography. Their use has become increasingly widespread since their introduction in 1990, and nowadays most analytical laboratories use or have used SPME as an efficient and green method to perform analyte extraction and sample clean-up in one step. The SPME technique is intrinsically flexible, and allows for a high degree of optimization with regard to the extracting phase, as well as the way sample is analyzed. Since its introduction, researchers have been trying different ways to transfer analytes extracted from the solid phase to a mass spectrometer, with the aim to increase throughput and reduce solvent, gas usage and costs associated with conventional chromatographic techniques. Furthermore, but not less important, for pure fun of developing new, more efficient and sensitive analytical strategies! This chapter aims at providing a comprehensive overview of the most relevant non-chromatographic mass spectrometric approaches developed for SPME. Technical aspects of each SPME-MS approach will be discussed, highlighting their advantages, disadvantages and future potential developments. Particular emphasis will be given on the most recent direct coupling approaches using novel ionization approaches, and a concise overview of the existing applications will also be provided.

Assessment of Volatile Chemical Composition of the Essential Oil of Jatropha ribifolia (Pohl) Baill by HS-SPME-GC-MS Using Different Fibers

The chemical composition of essential oil and volatile obtained from the roots of Jatropha ribifolia (Pohl) Baill was performed in this work. The Clevenger extractor was utilized in hydrodistillation of oil and chemical composition determined by gas chromatography coupled with mass spectrometry detector (GC-MS). The identification of compounds was confirmed by retention index (Kovats index) obtained from a series of straight chain alkanes (C7-C30) and by comparison with NIST and ADAMS library. A total of 61 compounds were identified in essential oil by GC-MS. The extraction of volatile was performed also by the use of the solid phase microextraction (SPME) with four different fibers. The essential oil extraction was extremely rapid (15 s) to avoid saturation of the fiber and the MS detector. The majority of the composition of essential oil is the terpenes: β-pinene (major compound 9.16%), β-vatirene (8.34%), α-gurjunene (6.98%), α-pinene (6.35%), camphene (4.34%), tricyclene (3.79%) and dehydro aromadendrene (3.52%) it and aldehydes and alcohols. Through the SPME it was possible to determine the nine volatile compounds not identified in oil 2,3,4-trimethyl-2-cyclopenten-1-one, α-phellandrene, 3-carene, trans-p-mentha-2,8-dienol, pinocamphone, D-verbenon, 1,3,3-trimethyl-2-(2-methyl-cyclopropyl)-cyclohexene, 2,4-diisocyanato-1-methylbenzene, and (6-hydroxymethyl-2,3-dimethylehenyl) methanol.

Optimization of some experimental parameters in the electro membrane extraction of chlorophenols from seawater

An electro membrane extraction (EME) methodology was utilized to study the isolation of some environmentally important pollutants, such as chlorophenols, from aquatic media based upon the electrokinetic migration process. The analytes were transported by application of an electrical potential difference over a supported liquid membrane (SLM). A driving force of 10V was applied to extract the analytes through 1-octanol, used as the SLM, into a strongly alkaline solution. The alkaline acceptor solution was subsequently analyzed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. The parameters influencing electromigration, including volumes and pH of the donor and acceptor phases, the organic solvent used as the SLM, and the applied voltage and its duration, were investigated to find the most suitable extraction conditions. Since the developed method showed a rather high degree of selectivity towards pentachlorophenol (PCP), validation of the method was performed using this compound. An enrichment factor of 23 along with acceptable sample clean-up was obtained for PCP. The calibration curve showed linearity in the range of 0.5-1000ng/mL with a coefficient of estimation corresponding to 0.999. Limits of detection and quantification, based on signal-to-noise ratios of 3 and 10, were 0.1 and 0.4ng/mL, respectively. The relative standard deviation of the analysis at a PCP concentration of 0.5ng/mL was found to be 6.8% (n=6). The method was also applied to the extraction of this contaminant from seawater and an acceptable relative recovery of 74% was achieved at a concentration level of 1.0ng/mL.