Application of a new hybrid organic-inorganic monolithic column for efficient deoxyribonucleic acid purification

Carboxyl-functionalized hybrid monolithic column prepared by "thiol-ene" click reaction for noninvasive speciation analysis of chromium with inductively coupled plasma-mass spectrometry

A novel carboxyl-functionalized hybrid monolithic column was developed based on "thiol-ene" click reaction via "one-pot" by choosing mercaptosuccinic acid, γ-methyl methacrylate trimethoxysilane and tetramethoxysilane as reaction monomers. The design of the hybrid monolithic column was assisted by the comparison in computational simulation with existing carboxyl-functionalized materials. The characterization by scanning electron microscopy, energy dispersive X-ray spectroscopy, N₂ adsorption-desorption measurement, Fourier-transform infrared spectroscopy and elemental analysis showed that the carboxyl-functionalized material has the advantages of good permeability and high mechanical strength. Then, we used the prepared carboxyl-hybrid monolith column as solid phase microextraction adsorbent for separation of trace inorganic chromium species. Under pH 4.5, the hybrid monolith column can selectively enrich Cr(III) without adsorbing Cr(VI) and afterwards, Cr(III) can be eluted by 1.0 mol L^-1 HCl. The chromium speciation separation method based on carboxyl-hybrid monolith column followed by inductively coupled plasma-mass spectrometry possessed the merits of facile preparation, low cost, simple and mild extraction condition, and sensitive detection, which has been successfully applied to the separation, enrichment and detection of inorganic chromium in environmental waters.

Recent advances in preparation and application of hybrid organic-silica monolithic capillary columns

Hybrid organic-silica monolithic columns, regarded as a second generation of silica-based monoliths, have received much interest due to their unique properties over the pure silica-based monoliths. This review mainly focuses on development in the fields of preparation of hybrid monolithic columns in a capillary and their application for CEC and capillary liquid chromatography separation, as well as for sample pretreatment of solid-phase microextraction and immobilized enzyme reactor since July 2010. The preparation approaches are comprehensively summarized with three routes: (i) general sol-gel process using trialkoxysilanes and tetraalkoxysilanes as coprecursors; (ii) "one-pot" process of alkoxysilanes and organic monomers concomitantly proceeding sol-gel chemistry and free radical polymerization; and (iii) other polymerization approaches of organic monomers containing silanes. The modification of hybrid monoliths containing reactive groups to acquire the desired surface functionality is also described.

Determination of anions using monolithic capillary column ion chromatography with end-to-end differential contactless conductometric detectors under resonance approach

An end-to-end differential measurement approach with capacitively coupled contactless conductivity detection (C(4)D) was applied to anion-exchange monolithic capillary column ion chromatography. The column was prepared by thermally initiated radical polymerization of poly(glycidyl methacrylate) in a fused-silica capillary of 320 μm i.d. and modified by quaternary ammonium latex surface coating. Two C(4)Ds were placed near both ends of the capillary column and the output difference between them was measured. With 15 mM potassium hydrogen phthalate used as the eluent, good separation of a mixture of inorganic anions (F(-), Cl(-), NO(2)(-), NO(3)(-)) was achieved. The detection limits of conventional C(4)D are 1.6, 0.28, 0.53, and 0.47 mg L(-1) for F(-), Cl(-), NO(2)(-), and NO(3)(-), respectively. To further enhance the sensitivity, the capacitive impedance from C(4)D was neutralized by an inductive impedance from a piezoelectric resonator. An increase in sensitivity by a factor of 7-8 was achieved in the resonating C(4)D in comparison with the conventional C(4)D. The detection limits of the resonating C(4)D are 0.23, 0.041, 0.065, and 0.059 mg L(-1) for F(-), Cl(-), NO(2)(-), and NO(3)(-), respectively. The response of the resonating C(4)D was analyzed based on an equivalent circuit model.

In-line coupling SPE and CE for DNA preconcentration and separation

An in-line SPE method coupled to CE was developed for the analysis of DNA. The amino silica monolith was prepared in situ by polymerization of tetraethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane in ethanol aqueous solution at the inlet end of a 100 μm id fused-silica capillary, and the remaining part of the capillary was used as separation channel. The procedure for this in-line SPE-CE method was constructed on the basis of investigation on operational conditions such as the introduction mode of sieving matrix, the composition of elution solvent and the elution time. Twenty millimolar ammonium hydroxide was demonstrated to be effective for DNA desorption from the monolith, and linear poly(N-isopropylacrylamide) was used as the separation matrix. The proposed method could achieve limits of detection of 0.065-0.123 ng/mL for six DNA fragments ranging 100-2000 bp. Compared with conventional CE, preconcentration factors of over 100 times were obtained. The applicability of the in-line SPE-CE method was further demonstrated by analyzing plasmid DNA from Escherichia coli crude lysate.

Ribonucleotide and ribonucleoside determination by ambient pressure ion mobility spectrometry

Detection limits and reduced mobilities for 12 ribonucleotides and 4 ribonucleosides were measured by ambient pressure electrospray ionization-ion mobility spectrometry (ESI-IMS). With the instrument used in this study it was possible to separate some of these compounds within mixtures. Detection limits reported for ribonucleotides and ribonucleosides ranged from 15 to 300 pmol and the reduced mobilities ranged from 41 to 56 suggesting that ambient pressure ESI-IMS may be used for their rapid and sensitive separation and detection. This report demonstrates that it was possible to use ion mobility spectrometry (IMS) to obtain a spectrum for the separation of nucleotides and nucleosides in less than 1 min. The application holds great promise for nucleotide analysis in the area of separating DNA fragments in genome sequencing and also for forensics DNA typing examinations used for the identification of blood stains in crime scenes and paternity testing.

Rapid recovery of DNA from agarose gel slices by coupling electroelution with monolithic SPE

An amino silica monolithic column prepared by in situ polymerization of tetraethoxysilane and N-(beta-aminoethyl)-gamma-aminopropyltriethoxysilane was firstly applied to recover DNA from agarose gel slices by coupling electroelution with monolithic SPE. DNA was electroeluted from the agarose gel slices onto the amino silica monolithic column. The DNA adsorbed on this monolithic column was then recovered using sodium phosphate solution at pH 10. The whole recovery procedure could be completed within 10 min because the use of amino silica monolithic column accelerated the DNA capture and facilitated the DNA release. Electroelution conditions, such as buffer pH, buffer concentration and applied voltage, were online optimized. The average yield for herring sperm DNA, pBR 322 DNA and lambda DNA recovered from 1.0% w/v agarose gel slices were 55+/-4, 50+/-6 and 42+/-7% (n=3), respectively. The polymerase chain reaction performance of pGM plasmid recovered from agarose gel slices demonstrated that the method could provide high-quality DNA for downstream processes. The combination of electroelution with monolithic SPE allows a rapid, simple and efficient DNA recovery method. This technique is especially useful for applications that need to purify small starting amounts of DNA.