Different Classes Of Analytes Research Articles

Copper Oxide Anchored Carbon Nanofibers: A Versatile Platform for Multiplex Detection of Antibiotics, Heavy Metals and Pesticides.

Electrochemical sensors offer promising prospects for real-time pollutant monitoring. In this study, copper oxide-dispersed graphitic carbon nanofibers (CuO-CNFs) grown via chemical vapour deposition were employed as a robust platform for detecting a variety of environmental pollutants. This array-based sensor adeptly identifies three different classes of analytes, i. e., antibiotics (chloramphenicol (CP) and tylosin tartrate (TT)), heavy metals (cadmium (Cd) and lead (Pb)), and pesticides (quinalphos (QP) and imidacloprid (IP)). Electron collection is facilitated by a glassy carbon electrode, while various physico-electrochemical methods delve into the properties of CuO-CNFs. The CuO-CNF-modified GCE array rapidly discerns (<15 sec) a broad linear range: 1-20 ppm for CP, 1-13.33 ppm for TT, 0.66-11.66 ppm for Cd, 20-33.33 ppm for Pb, 1.6-11.6 ppm for QP, and 5-25 ppm for IP, boasting quantification limits of 1.0, 1.0, 0.66, 20.0, 1.6, and 5.0 ppm for CP, TT, Cd, Pb, QP, and IP, respectively. Notably, this sensor achieves simultaneous identification of mixed analytes, including CP and TT, Cd and Pb, and QP and IP, within real tap water. Furthermore, the electrochemical sensor exhibits robustness; heightened sensitivity, selectivity, and stability; a swift response; and impressive reproducibility in detecting CP, TT, Cd, Pb, QP, and IP within aqueous samples. Consequently, this array-based electrochemical sensor has emerged as a rapid and simultaneous detection tool for diverse pollutant residues in surface and groundwater samples.

P-Terphenyl-based rigid stationary phases with embedded polar groups for liquid chromatography

Terphenyls are important building blocks for a wide range of functional molecules. Among the three isomers, p-terphenyl (C18H14) is particularly useful for the construction of optical devices on account of its unique structure. Herein, two rigid stationary phases bearing p-terphenyl as an external moiety and variable embedded carbamate groups (p-TerC with one embedded carbamate group and p-TerC2 with two embedded carbamate group) were presented. The proposed stationary phases were characterized by various means and evaluated in reversed-phase (RP) mode, using different classes of analytes, including polycyclic aromatic hydrocarbons (PAHs), alkylbenzenes, 4-alkylbiphenyls, substituted ureas, sulfonylureas, substituted sulfanilamides and aromatic acids. The comparison with conventional C18, several other polar-embedded aromatic and C18 equivalents indicated p-terphenyl-based stationary phases were featured by multiple retention mechanisms, involving π-π interaction, charge-transfer interaction, hydrogen-bonding and hydrophobic interaction in RP mode. A unusually high specificity to the analytes with linear structures was observed, as exemplified by an irreversible adsorption of tetracene and a readily separation of tetraphene and chrysene. The aliphatic linker used in the proposed stationary phases was an influential factor for retentivity, selectivity and column efficiency. Interestingly, p-TerC2 was operable in normal-phase mode for the separation of certain PAHs through polar-related interactions. The linear, rigid polyphenyl structure of p-terphenyl endowed the new stationary phase with distinctive chromatographic properties, in contrast to those of the preceding counterparts bonded with alkyl and/or polynuclear aromatic moieties.

Preparation and chromatographic performance of cardanol-bonded silica stationary phase

天然产物作为一种绿色低毒、来源广泛、功能位点丰富的单体,已被广泛应用于色谱固定相的研制与开发。该文以天然可再生资源腰果酚为配体,通过一步法开环反应将其接枝到由γ-缩水甘油醚氧丙基三甲氧基硅烷(KH-560)修饰的硅胶上,制备得到腰果酚键合硅胶固定相。利用傅里叶红外光谱、元素分析、热失重分析和N2吸附脱附实验对固定相进行表征,结果表明成功制备了腰果酚键合硅胶色谱固定相。采用Tanaka实验试剂、烷基苯、多环芳香烃、苯酚类化合物和芳香族位置异构体为探针评价其分离性能和保留机制,并与C18柱进行对比。研究发现,腰果酚键合固定相除疏水作用外,还具有π-π和氢键作用。基于上述保留作用,腰果酚键合硅胶固定相对测试探针表现出良好的分离性能。重复进样10次,各探针保留时间的RSD为0.052%~0.079%,峰面积的RSD为0.104%~0.847%,峰高的RSD为0.081%~0.272%,表明该色谱柱具有良好的重复性和稳定性。此外,腰果酚键合硅胶色谱柱对中药喜树果和吴茱萸果的粗提物具有良好的分离性能,验证了其在实际样品分析中的巨大潜力。将天然产物腰果酚用于色谱固定相的制备,为分离纯化喜树碱和吴茱萸提供了新的方法,同时拓展了腰果酚在色谱分离材料方面的应用。

Impedimetric Chemosensing of Volatile Organic Compounds Released from Li-Ion Batteries.

Detection of toxic and flammable gases and volatile organic compounds (VOCs) released from Li-ion batteries during thermal runaway can generate an early warning. A submicron (∼0.15 μm)-thick poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) sensor film is coated on a platinum electrode through a facile aqueous dispersion. The resulting sensor reliably detected different volatile organic compounds (VOCs) released during the early stages of thermal runaway of lithium-ion batteries (LIBs) even at low concentrations. The single-electrode sensor utilizes impedance spectroscopy to measure ethyl methyl carbonate and methyl formate concentrations at 5, 15, and 30 ppm independently and in various combinations using ethanol as a reference. In contrast to DC resistance measurement, which provides a single parameter, impedance spectroscopy provides a wealth of information, including impedance and phase angle at multiple frequencies as well as fitted charge transfer resistance and constant-phase elements. Different analytes influence the measurement of different parameters to varying degrees, enabling distinction using a single sensing material. The response time for ethyl methyl carbonate was measured to be 6 s. Three principal components (PCs) preserve more than 95% of information and efficiently enable discrimination of different classes of analytes. Application of low-power PEDOT:PSS-based gas sensors will facilitate cost-effective early detection of VOCs and provide early warning to battery management systems (BMS), potentially mitigating catastrophic thermal runaway events.

A review on recent applications of deep eutectic solvents in microextraction techniques for the analysis of biological matrices

In general, the analysis of biological matrices is challenging and a sample preparation step employing extraction/cleanup techniques is required. Liquid-phase microextraction using deep eutectic solvents has been exploited in numerous applications because these solvents exhibit fascinating physico-chemical properties in addition to simple and straightforward preparation. Varied configurations and strategies have been examined for the determination of different classes of analytes, and these methodologies offer environmentally friendly workflows with low solvent and sample consumption, rapid and simple experimental procedures, and satisfactory analytical performance. In this review, developments related to the use of deep eutectic solvents in microextraction approaches for the analysis of biological matrices are briefly discussed with a focus on studies reported from 2017 to 2021.

Multiplexing of Electrospray Ionization Sources Using Orthogonal Injection into an Electrodynamic Ion Funnel.

In this contribution, we report an efficient approach to multiplex electrospray ionization (ESI) sources for applications in analytical and preparative mass spectrometry. This is achieved using up to four orthogonal injection inlets implemented on the opposite sides of an electrodynamic ion funnel interface. We demonstrate that both the total ion current transmitted through the mass spectrometer and the signal-to-noise ratio increase by 3.8-fold using four inlets compared to one inlet. The performance of the new multiplexing approach was examined using different classes of analytes covering a broad range of mass and ionic charge. A deposition rate of >10 μg of mass-selected ions per day may be achieved by using the multiplexed sources coupled to preparative mass spectrometry. The almost proportional increase in the ion current with the number of ESI inlets observed experimentally is confirmed using gas flow and ion trajectory simulations. The simulations demonstrate a pronounced effect of gas dynamics on the ion trajectories in the ion funnel, indicating that the efficiency of multiplexing strongly depends on gas velocity field. The study presented herein opens up exciting opportunities for the development of bright ion sources, which will advance both analytical and preparative mass spectrometry applications.

Targets and Tools: Nucleic Acids for Surface-Enhanced Raman Spectroscopy.

Surface-enhanced Raman spectroscopy (SERS) merges nanotechnology with conventional Raman spectroscopy to produce an ultrasensitive and highly specific analytical tool that has been exploited as the optical signal read-out in a variety of advanced applications. In this feature article, we delineate the main features of the intertwined relationship between SERS and nucleic acids (NAs). In particular, we report representative examples of the implementation of SERS in biosensing platforms for NA detection, the integration of DNA as the biorecognition element onto plasmonic materials for SERS analysis of different classes of analytes (from metal ions to microorgniasms) and, finally, the use of structural DNA nanotechnology for the precise engineering of SERS-active nanomaterials.

Octadecylimidazolium ionic liquids-functionalized carbon dots and their precursor co-immobilized silica as hydrophobic chromatographic stationary phase with enhanced shape selectivity

In this work, 1-vinyl-3-octadecylimidazolium bromide ionic liquids ([C18VIm]Br) and their derived carbon dots (ImC18CDs) were prepared, [C18VIm]Br and ImC18CDs were grafted on the silica to obtain Sil-ImC18 and Sil-ImC18CDs, respectively, and they were also co-grafted on silica which named Sil-ImC18/CDs. Compared with Sil-ImC18 and Sil-ImC18CDs columns, Sil-ImC18/CDs column exhibited enhanced selectivity for separation of tetracyclic/tricyclic polycyclic aromatic hydrocarbon (PAH) isomers, and butylbenzene isomers in reversed-phase liquid chromatography, which may be due to the synergistic effect between ImC18CDs and [C18VIm]Br, the π-π interaction between imidazolium and analytes, etc. Meanwhile, the retention behavior of Sil-ImC18/CDs was further evaluated and compared with the commercial C18 column using different classes of analytes, including standard test mixtures of Tanaka, Engelhardt, SRM869b, SRM870. The results demonstrated that co-grafted column exhibited superior separation performance. And this column was applied to determine the contents of calycosin-7-glucoside, ononin, calycosin and formononetin in the extract of Radix Astragali, which were found that the concentration was 0.25 mg mL−1, 0.15 mg mL−1, 0.13 mg mL−1 and 0.30 mg mL−1, respectively.

A docosyl-terminated polyamine amphiphile-bonded stationary phase for multimodal separations in liquid chromatography

A convenient synthetic approach to a linear alkyl-polyamine amphiphilic chromatographic selector was proposed. Successive immobilization of the amphiphile onto silica gel afforded a multimodal stationary phase for high-performance liquid chromatography (HPLC). The as-prepared silica material was studied comparatively with a conventional octadecyl (C18) and an amide-embedded C18 stationary phase. The new uniform docosyl-triamine tandem was featured by an enhanced shape selectivity towards geometric isomers, and a low silanol activity towards alkaline solutes. The presence of multiple amino groups rendered the new adsorbent operable in different modes, such as hydrophilic interaction and ion-exchange modes. The satisfactory performance of the said stationary phase in separating different classes of analytes, including polycyclic aromatic hydrocarbons, flavonoids, tricyclic antidepressants, calcium channel blockers, aromatic acids, inorganic anions, nucleosides and estrogens, revealed its great potential and high adaptability for multipurpose LC utility.

The Chemistry of Paper in Paper Spray Ionization Mass Spectrometry

There are many rapidly evolving technologies that use simple papers as a surface for chemical reactions and detection of molecules. One example of this application is the use of paper as a surface for ionization and introduction of compounds into mass spectrometry. The current work was designed to investigate mechanisms of interaction between the paper and analytes using mass spectrometry as the detection instrument. Standard compounds with different sizes were used in this study. Factors investigated include the effects of the paper geometry (5 mm) and position (tp=90&amp;ordm;) were found to be optimal. The role of atmospheric water and the effects of paper porosity were affected the signals of the tested compounds. Investigations of the interaction of standard solutions with the paper surface indicated that atmospheric water is required for ionization. Up to three water molecules were detected in association with the analytes indicating that the presence of some water is required. In addition, this study showed the potential of silicon dioxide nanoparticles for eluting the standards compound from the paper surface. The impact of trace elements in the commercial papers and the interactions between the paper cellulose with different classes of analytes was investigated.

Tuning selectivity via electronic interaction: Preparation and systematic evaluation of serial polar-embedded aryl stationary phases bearing large polycyclic aromatic hydrocarbons

Aromatic stationary phases showing complementary selectivity to their alkyl counterparts are extremely useful for certain challenging separation tasks. Herein, a series of polar-embedded aryl stationary phases were synthesized from reactive derivatives of large polycyclic aromatic hydrocarbons (PAHs), including anthracene (three-ring, catacondensed), pyrene (four-ring, pericondensed) and triphenylene (four-ring, fully-benzenoid). These PAHs were functionalized with hydroxymethyl group (PAH-CH2OH), then catalytically converted to carbamates (PAH-CH2OC(=O)NH-R) using isocyanate, and finally covalently grafted onto silica to produce corresponding carbamate-embedded PAH stationary phases. To gain insight into the connection and difference among the attached species, the chromatographic behaviors of these new adsorbents were systematically evaluated in terms of surface coverage, hydrophobic and aromatic features, shape selectivity and charge-transfer property, using different classes of analytes, such as alkylbenzenes, PAH congeners and isomeric multi-substituted benzenes, and the results were further compared with conventional octadecyl ones (C18). The relationships between the shape selectivity and the surface chemistry revealed unique behavioral patterns of theses immobilized conjugated ligands, as well as marked differences amongst them, which formed sharp contrast to the case of C18. The effects of temperature and mobile phase compositions on the shape selectivity were further studied. The charge-transfer characteristics demonstrated the great potential of such polar-embedded PAH materials for highly selective separation of electron-deficient compounds through electron donor-acceptor complexation.

Ultrasound-assisted solvent extraction of porous membrane packed solid samples: A new approach for extraction of target analytes from solid samples

For the first time, a porous membrane-based method is proposed for the extraction of target analytes directly from the solid samples. This method involves the packing of solid sample inside a porous polypropylene membrane sheet whose edges are heat-sealed to fabricate a bag. This bag is immersed in a suitable solvent and the analytes are extracted by the application of ultrasound energy. The various factors that affect the extraction performance such as extraction solvent, ultrasonication time, and ultrasound power are suitably optimized. The scope of this extraction method is very general, it can be used for the extraction of different classes of analytes from a variety of solid samples using suitable extraction solvents. The beauty of this method lies in the fact that only the small molecules such as analytes can pass through the membrane while the interfering or complex matrix species cannot pass through the membrane bag to the extraction solvent. Previously, the solid samples were first digested/dissolved into liquid medium and then analytes were extracted by membrane-protected adsorbents involving adsorption and desorption steps. With the proposed procedure, the steps of digestion/dissolution and the adsorption of analytes onto a suitable adsorbent are eliminated. Likewise, the steps of filtration and centrifugation are not required as the solid is effectively packed inside the membrane bag. Moreover, the extraction device is low cost, portable, easy to fabricate, and simple to use in the extraction process. In this work, proof of the concept is demonstrated by the extraction of polyaromatic hydrocarbons from the soil samples using GC–MS. This method provided reasonably low LODs ranging from 0.19 to 0.93 ng/mg. The intra-day accuracy and precision ranged from 87.5 to 109% and 0.8 to 5%, respectively while recoveries varied from 75.1 ± 4.9 to 106 ± 4.5%.

A New Microchip Design. A Versatile Combination of Electromembrane Extraction and Liquid-Phase Microextraction in a Single Chip Device.

For the first time, a novel and versatile microfluidic device was developed to achieve the possibility of combining different extraction principles using a miniaturized approach for the extraction of different classes of analytes. This novel microchip is composed of a sandwich of three poly(methyl methacrylate) (PMMA) layers. Four channels allowed the combination of electromembrane extraction (EME) and liquid-phase microextraction (LPME) in three different ways: (I) EME and LPME, (II) EME and EME, or (III) LPME and LPME. The microchip can be used either (a) using a common acceptor phase (for both extractions) for the simultaneous extraction of drugs from different nature in a single step, or (b) a common sample solution (for both extractions) and two acceptor solutions for simultaneous drug separation. In this work, the performance of this novel microchip was demonstrated by simultaneous integration of EME and LPME using a common acceptor phase for both extractions. This configuration reduces the time of analysis allowing direct analysis in a single chip. The microchip was tested for extracting two different classes of analytes: five fluoroquinolones and four parabens as model analytes. All effective variables were optimized for EME and LPME. Under the optimized conditions, the reusable microchip enables simultaneous μ-EME/LPME with extraction efficiencies over 77% in only 8 min extraction and sample volume consumption lower than 40 μL. The optimized procedure was successfully applied to urine samples obtaining recoveries over 90% for all analytes.

A versatile polar-embedded polyphenyl phase for multimodal separation in liquid chromatography

A new polar-embedded aromatic stationary phase has been prepared by covalently attaching p-biphenylacetamide silane to silica spheres. The retention behavior of this phase was compared with an alkylamide counterpart and octadecyl phases using different classes of analytes, including geometric isomers and congeners from Standard Reference Materials 869b, 870 and 1647e, positional isomers of electron-deficient benzenes, as well as alkylbenzenes and alkylbiphenyls. The relationship between shape selectivity and surface chemistry of stationary phase was comparatively studied. Influences of the embedded group and ligand length and/or size on the chromatographic selectivity towards various congeners were established. The new polar-embedded aromatic phase possessed unique benzenoid affinity, enhanced aromatic selectivity, distinct charge-transfer properties, as well as good water-wettablity, as a result it can be employed in normal phase, reversed-phase and per-aqueous modes.

Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction

Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C12) and phenethyl (PhE) ligands. Here, the ability of the PF-C12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania–based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L−1 limit of detections (LOD) (4.2–26.3 ng L−1) for environmentally important analytes including polycyclic aromatic hydrocarbons, ketones and aliphatic hydrocarbons. In CME-GC experiments (n = 5), the capillary-to-capillary RSD value was ∼2.1%; such a low RSD value is indicative of excellent reproducibility of the sol-gel method used for the preparation of these CME coatings. The dual-ligand sol-gel coating provided stable performance in capillary microextraction of analytes from saline samples.

(Invited) Porphyrins Based Gas Sensors and Their Applications

The role of porphyrins in life processes is well known. Iron complexes for instance are prostetic groups of important proteins such as hemoglobine and cytochromes. On the other hand, reduced porphyrins, as magnesium chlorin complexes, are fundamental in the photosynthetic processes. Such richness of properties is particularly attractive for chemical sensing. The molecular framework of porphyrins is a unique site for a wide range of interaction mechanisms useful for analyte binding. the interactions span from Van der Waals forces to hydrogen bond, to π interactions and to the coordination to the central metal ion. The concurrence of all these mechanisms makes difficult the development of selective sensors, even if selectivity can in some cases found or improved by a suitable design of the sensor. On the other hand, the sensitivity of porphyrins can be oriented, through a proper molecular design, towards different classes of analytes. This control is of great value for the design of sensor arrays where several sensors non-selective but different among them are considered together. We have been interested since about two decades to the use porphyrins to develop sensors for volatile compounds and gases. The physical properties of porphyrins restrict the transduction mechanisms that can be exploited to create an electric signal from the porphyrin-analyte interaction. It is important to recall that a chemical sensor actually measures a physical quantity of the sensing material that is affected by the interaction with the analyte. We developed sensors measuring the mass, the optical absorbance, the surface potential and the charge transferred either to or from an inorganic semiconductor. The sensing properties in all these devices can be related to the properties of the individual porphyrins, for instance the Hard and Soft Acids and Bases (HSAB) Pearson’s rule can be invoked to elucidate the sensitivity of porphyrins coated quartz microbalance sensors with regards to amines and alcohols. In this paper, we will provide a rationale for the development of porphyrins based gas sensors discussing the pros and the cons of each transduction principle. A review of the applications will also be illustrated with a special emphasis on medical diagnosis through the analysis of volatile compounds.

Ambient Mass Spectrometry Imaging Using Direct Liquid Extraction Techniques.

Mass spectrometry imaging (MSI) is a powerful analytical technique that enables label-free spatial localization and identification of molecules in complex samples.1-4 MSI applications range from forensics5 to clinical research6 and from understanding microbial communication7-8 to imaging biomolecules in tissues.1, 9-10 Recently, MSI protocols have been reviewed.11 Ambient ionization techniques enable direct analysis of complex samples under atmospheric pressure without special sample pretreatment.3, 12-16 In fact, in ambient ionization mass spectrometry, sample processing (e.g., extraction, dilution, preconcentration, or desorption) occurs during the analysis.17 This substantially speeds up analysis and eliminates any possible effects of sample preparation on the localization of molecules in the sample.3, 8, 12-14, 18-20 Venter and co-workers have classified ambient ionization techniques into three major categories based on the sample processing steps involved: 1) liquid extraction techniques, in which analyte molecules are removed from the sample and extracted into a solvent prior to ionization; 2) desorption techniques capable of generating free ions directly from substrates; and 3) desorption techniques that produce larger particles subsequently captured by an electrospray plume and ionized.17 This review focuses on localized analysis and ambient imaging of complex samples using a subset of ambient ionization methods broadly defined as “liquid extraction techniques” based onmore » the classification introduced by Venter and co-workers.17 Specifically, we include techniques where analyte molecules are desorbed from solid or liquid samples using charged droplet bombardment, liquid extraction, physisorption, chemisorption, mechanical force, laser ablation, or laser capture microdissection. Analyte extraction is followed by soft ionization that generates ions corresponding to intact species. Some of the key advantages of liquid extraction techniques include the ease of operation, ability to analyze samples in their native environments, speed of analysis, and ability to tune the extraction solvent composition to a problem at hand. For example, solvent composition may be optimized for efficient extraction of different classes of analytes from the sample or for quantification or online derivatization through reactive analysis. In this review, we will: 1) introduce individual liquid extraction techniques capable of localized analysis and imaging, 2) describe approaches for quantitative MSI experiments free of matrix effects, 3) discuss advantages of reactive analysis for MSI experiments, and 4) highlight selected applications (published between 2012 and 2015) that focus on imaging and spatial profiling of molecules in complex biological and environmental samples.« less

Interface-free two-dimensional heart-cutting capillary electrophoresis for the separation and stacking of anionic and neutral analytes.

Interface-free two-dimensional heart-cutting capillary electrophoresis for two different classes of analytes (anionic and neutral) in a single capillary is presented. Simultaneous sample stacking and orthogonal separation were demonstrated. The anionic species were first analyzed by capillary zone electrophoresis in the first dimension. Then, the neutral compounds were separated in the second dimension by micellar electrokinetic chromatography using the common anionic surfactant sodium dodecyl sulfate. The first and second dimensions occurred automatically without changing the electrolyte and without polarity switching. Artificial mixtures (five anions and four neutral compounds) were successfully analyzed with sensitivity enhancement factors from 7 to 28. The orthogonal separation was complete within 8 min. Some analytical features and application to a spiked real river water sample were also studied.

A polar-embedded C30 stationary phase: Preparation and evaluation

A novel polar-embedded C30 stationary phase has been synthesized and characterized. The polar carbamate group was generated homogeneously in situ by the catalytic reaction between isocyanate and primary alcohol. The simple one-pot synthetic strategy provided an efficient and effective strategy for modification of silica spheres. Efficiency, selectivity and silanol activity of the resulting column were characterized in detail with different classes of analytes that included Standard Reference Materials (SRM) 870, SRM 869b and SRM 1647e, alkylbenzene congeners, as well as polar-substituted aromatics. The polar-embedded C30 stationary phase was found to exhibit excellent shape selectivity.

Combining serum autoantibody measurements with traditional serum biomarkers for the detection of invasive breast cancer.

13 Background: The use of protein biomarkers for serum-based detection of invasive breast cancer has been problematic due in large part to intrinsic variability in the population as a whole. The Provista Biomarker Assay (PBA) has been shown previously to be highly sensitive across a wide spectrum of clinical signals. The detection of autoantibodies (AAb) holds great promise due to the inherent specificity these biomarkers provide. However, as a clinical-quality diagnostic, it is necessary to utilize a panel comprised of multiple autoantibodies, as individual sensitivity is general low. Our hypothesis was that combining serum protein and autoantibodies together in a panel would result in an increased ability to correctly identify breast cancer. Methods: To maximize clinical performance (sensitivity and specificity), we utilized the Meso Scale Discovery ELISA-based system to measure AAbs from patient sera. We analyzed 134 prospectively collected patient serum samples for a variety of autoantibody targets. These data, together with serum protein biomarker concentrations, produced an analytically robust test that is also highly specific. Results: Consistent with our hypothesis, the inclusion of autoantibodies with serum proteins in the Provista Biomarker Assay improved test specificity above that observed in serum protein biomarkers alone. Individual protein targets had limited ability to differentiate benign conditions from invasive breast cancer. However, factoring in autoantibody values resulted in improved overall accuracy to differentiate serum from benign and invasive breast cancer patients. Conclusions: In the novel approach of combining these two different classes of analytes, we exploit the specificity of AAbs while maintaining high sensitivity through the inclusion of more generalized cancer-associated protein biomarkers. The combination of these two approaches clearly offers unique performance benefits in the early detection of invasive breast cancer that is greater than either component alone.