Characterization of the changes in polarity of natural organic matter using solid-phase extraction: introducing the NOM polarity rapid assessment method (NOM-PRAM) (original) (raw)
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Applied in Solid Phase Extraction for Some Polar Compounds
2011
Two basic mechanisms were applied for studying some polar compounds of pharmaceutical interest (captopril, atenolol, and metformin) by solid phase extraction, using an octadecilsilica based adsorbent. The retention of these compounds was achieved under reversedphase or ion-pair mechanisms using cartridges containing two different sorbent loadings. The breakthrough parameters (hold-up, breakthrough, and retention volumes) were measured for chosen model solutes from the experimental data obtained by percolating the C18 cartridges with stock solutions for each compound. The experimental curves were fitted by means of Boltzmann’s function, and the regression parameters were used in calculating the breakthrough parameters. key words: solid phase extraction; retention; breakthrough; C18; Boltzmann’s function. received: November 3, 2010 accepted: December 15, 2010
Although PPL-based solid-phase extraction (SPE) has been widely used before dissolved organic matter (DOM) analyses via advanced measurements such as ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), much is still unknown about the structural and compositional changes in DOM pool through SPE. In this study, selected DOM from various sources were tested to elucidate the differences between before and after the SPE utilizing multiple analytical tools including fluorescence spectroscopy, FT-ICR-MS, and size exclusion chromatography with organic carbon detector (SEC-OCD). The changes of specific UV absorbance indicated the decrease of aromaticity after the SPE, suggesting a preferential exclusion of aromatic DOM structures, which was also confirmed by the substantial reduction of fluorescent DOM (FDOM). Furthermore, SEC-OCD results exhibited very low recoveries (1–9 %) for the biopolymer fraction, implying that PPL needs to be used cautiously in SPE sorbent materials for treating high molecular weight compounds (i.e., polysaccharides, proteins, and amino sugars). A careful examination via FT-ICR-MS revealed that the formulas lost by the SPE might be all DOM sourcedependent. Nevertheless, the dominant missing compound groups were identified to be the tannins group with high O/C ratios (>0.7), lignins/carboxyl-rich alicyclic molecules (CRAM), aliphatics with high H/C >1.5, and heteroatomic formulas, all of which were prevailed by pseudo-analogous molecular formula families with different methylene (−CH2) units. Our findings shed new light on potential changes in the compound composition and the molecular weight of DOM upon the SPE, implying precautions needed for data interpretation.
Solid-phase extraction of polar compounds with a hydrophilic copolymeric sorbent
Journal of Chromatography A, 2004
A new synthesized copolymer based on N-vinylimidazole-divinylbenzene (VIm-DVB) was tested as a sorbent for the solid-phase extraction (SPE) of polar analytes. In the on-line SPE, this synthesized sorbent enabled 100 ml of sample to be preconcentrated with recoveries as high as 80% for oxamyl, phenol (Ph) and derivates, bentazone and (4-chloro-2-methylphenoxy)acetic acid (MCPA). For the off-line SPE, 1000 ml of sample was extracted and recoveries were higher than 92% for all compounds with the exception of oxamyl (83%) and methomyl (78%). The VIm-DVB sorbent gives better recoveries than the previously synthesized 4-vinylpyridine-divinylbenzene (VP-DVB) resin and similar to such highly crosslinked commercial sorbents as LiChrolut EN or Oasis HLB. Real water samples were used to validate the on-line SPE method. Linearity was good and detection limits were between 0.1 and 0.2 g l −1 .
Water Environment Research, 2009
This paper introduces a novel natural organic matter (NOM) fractionation technique using solid-phase extraction cartridges. The new technique requires only 6 hours of fractionation time, which is much faster than traditional fractionation techniques (24 hours). It uses three Bond Elute ENV cartridges (Varian, Inc., Lake Forest, California), one Strata X-C cartridge (Phenomenex, Torrance, California), and one Strata X-AW cartridge (Phenomenex) in series and was tested by using to fractionate NOM from Suwannee River, Georgia (SRNOM) and Red River, Minnesota (RRNOM). Hydrophobic acid was a major fraction and accounted for 66 to 70% and 36% of SRNOM and RRNOM, respectively. The NOM fractions obtained from the developed method were characterized using Fourier transformed infrared spectroscopy and 13 C nuclear magnetic resonance. The acid fractions of SRNOM mainly consisted of carboxylic acids. An application of this new technique was demonstrated by using it to investigate the effectiveness of water treatment processes in removing different NOM fractions. Water Environ. Res., 81, 2299Res., 81, (2009.
Chromatographia, 2004
Two 4-vinylimidazole-divinylbenzene (4VIm-DVB) polymers were synthesized and applied as sorbents for on-line solid-phase extraction (SPE) followed by liquid chromatography for analyzing polar compounds in aqueous samples. The new sorbents (4VIm-DVB) were compared to another sorbent that had been previously synthesized by our group (N-vinylimidazoledivinylbenzene (NVIm-DVB)) and to the commercial OASIS Ò HLB and Strata TM X. All the sorbents enabled 100 mL of sample to be on-line concentrated with good recoveries for the studied polar compounds. Real water samples were analyzed using NVIm-DVB and OASIS Ò HLB as SPE sorbent, for which the best results were obtained.
Journal of Separation Science, 2011
A solid-phase extraction element based on epoxy polymer monolith was fabricated for sorptive enrichment of polar compounds from liquid and gaseous samples. After ultrasonication of the element in an aqueous solution for a given period of time, the thermal desorption (TD) using a pyrolyzer with gas chromatography/mass spectrometry (GC/MS), in which TD temperature was programmed from 50 to 2501C for the analytes absorbed in the element, was used to evaluate the element for basic extraction performance using the aqueous standard mixtures consisting of compounds having varied polarities such as hexanol, isoamyl acetate, linalool, furfural and decanoic acid, in concentrations ranging from 10 mg/L to 1 mg/L. Excellent linear relationships were observed for all compounds in the standard mixture, except decanoic acid. In the extraction of beverages such as red wine, the extraction element showed stronger adsorption characteristics for polar compounds such as alcohols and acids than a non-polar polydimethylsiloxane-based element. This feature is derived from the main polymer structure along with hydroxyl and amino groups present in the epoxy-based monolith polymer matrix.
The Benefits and Limitations of Methods Development in Solid Phase Extraction: Mini Review
Jurnal Teknologi, 2014
Over recent years, there has been an explosive growth of sample preparation techniques. Sample preparation is in most cases meant to be the isolation online or offline concentration of some components of interest or target analytes. Solid phase extraction (SPE) is a very popular technique nowadays in sample preparation. The principal is quite similar with liquid- liquid extraction (LLE) which involves partition of solutes between two phases. But, there are some differences between them and some benefits and limitations of difference types of SPE technique like presented in this paper.
Chromatographia, 2019
This paper presents an overview of the more recent applications of solid-phase extraction (SPE, from January 2015 to September 2018, which have been recorded in Web of Science) in preparation of food and environmental samples. First, the history, milestones, principles, and features of different formats of SPE are discussed. In addition, miniaturization of SPE techniques and comparison of classical SPE and miniaturized SPE-called dispersive micro solid-phase extraction (D-μ-SPE)-are covered. Next, the published applications in extraction and separation of diverse organic and inorganic analytes from a variety of food and environmental samples are classified on the basis of their sorbents including layered double hydroxide, metal organic frameworks, carbon nanotube-based sorbents, graphene-based sorbents, β-cyclodextrinbased sorbents, dendrimer-based sorbents, molecular or ion recognition sorbents, and restricted access materials. Finally, the future trends in this area are discussed. Keywords Solid-phase extraction • Miniaturization • Advanced sorbents • Food samples • Environmental samples Abbreviations 17β-E2 17β-Estradiol 2-PTSC 2-Pyridinecarboxaldehyde thiosemicarbazone AAS Atomic absorption spectrometry ACN Acetonitrile BET Brunauer-Emmette-Teller BP Buckypaper BPA Bisphenol A BSA Bovine serum albumin BTEXs Benzene, toluene, ethylbenzene, and xylenes CD Cyclodextrin CNT Carbon nanotube D-µ-SPE Dispersive micro solid-phase extraction DLR Dynamic linear range DSPE Dispersive solid-phase extraction FAAS Flame atomic absorption spectrometry FTIR Fourier-transform infrared spectroscopy G Graphene GAC Green analytical chemistry GC/NCI-MS Gas chromatography negative chemical ionization mass spectrometry GC Gas chromatography GCB Graphitized carbon black GC-ECD Gas chromatography-electron capture detection GC-FID Gas chromatography flame-ionization detection GC-FPD Gas chromatography-flame photometric detection G-CL Graphene on the zeolite clinoptilolite GC-MS Gas chromatography mass spectrometry
Retention Mechanisms Applied in Solid Phase Extraction for Some Polar Compounds
Two basic mechanisms were applied for studying some polar compounds of pharmaceutical interest (captopril, atenolol, and metformin) by solid phase extraction, using an octadecilsilica based adsorbent. The retention of these compounds was achieved under reversed-phase or ion-pair mechanisms using cartridges containing two different sorbent loadings. The breakthrough parameters (hold-up, breakthrough, and retention volumes) were measured for chosen model solutes from the experimental data obtained by percolating the C18 cartridges with stock solutions for each compound. The experimental curves were fitted by means of Boltzmann’s function, and the regression parameters were used in calculating the breakthrough parameters.