Direct analysis of pharmaceutical formulations from non‐bonded reversed‐phase thin‐layer chromatography plates by desorption electrospray ionisation ion mobility mass spectrometry

The direct analysis of pharmaceutical formulations and active ingredients from non‐bonded reversed‐phase thin layer chromatography (RP‐TLC) plates by desorption electrospray ionisation (DESI) combined with ion mobility mass spectrometry (IM‐MS) is reported. The analysis of formulations containing analgesic (paracetamol), decongestant (ephedrine), opiate (codeine) and stimulant (caffeine) active pharmaceutical ingredients is described, with and without chromatographic development to separate the active ingredients from the excipient formulation. Selectivity was enhanced by combining ion mobility and mass spectrometry to characterise the desorbed gas‐phase analyte ions on the basis of mass‐to‐charge ratio (m/z) and gas‐phase ion mobility (drift time). The solvent composition of the DESI spray using a step gradient was varied to optimise the desorption of active pharmaceutical ingredients from the RP‐TLC plates. The combined RP‐TLC/DESI‐IM‐MS approach has potential as a rapid and selective technique for pharmaceutical analysis by orthogonal gas‐phase electrophoretic and mass‐to‐charge separation. Copyright © 2009 John Wiley & Sons, Ltd.     

Desorption electrospray ionisation mass spectrometric analysis of chemical warfare agents from solid‐phase microextraction fibers

Desorption electrospray ionisation mass spectrometry (DESI‐MS) was recently reported for the direct analysis of sample media without the need for additional sample handling. During the present study, direct analysis of solid‐phase microextraction (SPME) fibers by DESI‐MS/MS was evaluated with indoor office media that might be collected during a forensic investigation, including wall surfaces, office fabrics, paper products and Dacron swabs used for liquid sampling. Media spiked at the µg/g level with purified chemical warfare agents and a complex munitions grade sample of tabun, to simulate the quality of chemical warfare agent that might be used for terrorist purposes, were successfully analysed by DESI‐MS/MS. Sulfur mustard, a compound that has not been successfully analysed by electrospray mass spectrometry in the past, was also sampled using a SPME fiber and analysed for the first time by DESI‐MS/MS. Finally, the overall analytical approach involving SPME headspace sampling and DESI‐MS analysis was evaluated during a scenario‐based training live agent exercise. A sarin sample collected by the military was analysed and confirmed by DESI‐MS in a mobile laboratory under realistic field conditions. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.     

Detection of the Short‐Lived Radical Cation Intermediate in the Electrooxidation of N,N‐Dimethylaniline by Mass Spectrometry

The N,N‐dimethylaniline (DMA) radical cation DMA^.+, a long‐sought transient intermediate, was detected by mass spectrometry (MS) during the electrochemical oxidation of DMA. This was accomplished by coupling desorption electrospray ionization (DESI) MS with a waterwheel working electrode setup to sample the surface of the working electrode during electrochemical analysis. This study clearly shows that DESI‐based electrochemical MS is capable of capturing electrochemically generated intermediates with half‐lives on the order of microseconds, which is 4–5 orders of magnitude faster than previously reported electrochemical mass spectrometry techniques.     

Analysis of lipids with desorption atmospheric pressure photoionization‐mass spectrometry (DAPPI‐MS) and desorption electrospray ionization‐mass spectrometry (DESI‐MS)

In this article, the effect of spray solvent on the analysis of selected lipids including fatty acids, fat‐soluble vitamins, triacylglycerols, steroids, phospholipids, and sphingolipids has been studied by two different ambient mass spectrometry (MS) methods, desorption electrospray ionization‐MS (DESI‐MS) and desorption atmospheric pressure photoionization‐MS (DAPPI‐MS). The ionization of the lipids with DESI and DAPPI was strongly dependent on the spray solvent. In most cases, the lipids were detected as protonated or deprotonated molecules; however, other ions were also formed, such as adduct ions (in DESI), [M‐H]⁺ ions (in DESI and DAPPI), radical ions (in DAPPI), and abundant oxidation products (in DESI and DAPPI). DAPPI provided efficient desorption and ionization for neutral and less polar as well as for ionic lipids but caused extensive fragmentation for larger and more labile compounds because of a thermal desorption process. DESI was more suitable for the analysis of the large and labile lipids, but the ionization efficiency for less polar lipids was poor. Both methods were successfully applied to the direct analysis of lipids from pharmaceutical and food products. Although DESI and DAPPI provide efficient analysis of lipids, the multiple and largely unpredictable ionization reactions may set challenges for routine lipid analysis with these methods. Copyright © 2012 John Wiley & Sons, Ltd.     

Simultaneous detection of sulfoxaflor and its metabolites,X11719474 and X11721061, in lettuce using a modified QuEChERS extraction method and liquid chromatography–tandem mass spectrometry

An analytical method has been developed to quantify the residual levels of sulfoxaflor and its metabolites (X11719474 and X11721061) in/on cultivated lettuce grown under greenhouse conditions. Samples were extracted and purified using a quick, easy, cheap, effective, rugged, and safe ‘QuEChERS’ method (original version) following systematic method optimization and were analyzed by liquid chromatography–tandem mass spectrometry (LC–MS/MS). Good linearity with coefficient of determination ≥0.9930 was obtained and the limits of detection (LOD) and quantification (LOQ) were in the ranges of 0.003–0.006 and 0.01–0.02 mg/kg, respectively. The recovery rates of both the parent compound and its metabolites (fortified at 10 and 50× the LOQ) estimated from six replicates ranged between 81.9 and 115.5% with a relative standard deviation <12%. The validated method was applied to field‐incurred samples (collected over 7 days) sprayed once or twice with a water‐dispersible granule formulation. Notably, a substantial reduction in rate was observed after 3 days and the half‐life was short, only 1.5 days. The developed method is simple and versatile and can be used for various leafy vegetables.     

Chemical profiling and separation of bioactive secondary metabolites in Maca (Lepidium peruvianum) by normal and reverse phase thin layer chromatography coupled to desorption electrospray ionization‐mass spectrometry

Maca is a Peruvian tuberous root of the Brassicaceae family grown in the central Andes between altitudes of 4000 and 4500 m. The medicinal plant is a nutraceutical with important biological activities and health effects. In this study, we report a rapid high‐performance thin layer chromatography (HPTLC)‐(?)desorption electrospray ionization (DESI)‐mass spectrometry (MS) method to profile and separate intact glucosinolates without prior biochemical modifications from the hydromethanolic extracts of two phenotypes, red and black Maca (Lepidium peruvianum) seeds. In the first stage of the plant's life cycle, aromatic glucosinolates were the main chemical constituents whereby six aromatic, three indole, and one aliphatic glucosinolate were tentatively identified. At the seedling stage, glucolepigramin/Glucosinalbin was the most predominant precursor, rather than Glucotropaeolin, which is mainly found in hypocotyls and roots. These findings lead us to suggest that glucolepigramin/glucosinalbin play a major role as active precursors in the biosynthetic pathways of other secondary metabolites in the early stages of plant development. Between red and black Maca seeds, only minor differences in the relative abundances of glucosinolates were observed rather than different plant metabolites. For the first time, we report six potential plant antibiotics, phytoanticipins: glycosylated ascorbigens and dihydroascorbigens from Maca seeds. We also investigated a targeted reverse phase C₁₈ functionalized TLC‐DESI‐MS method with high sensitivity and specificity for Brassicaceae fatty acids in Maca seeds and health supplements such as black Maca root lyophilized powder and tinctures. The investigation of secondary metabolites by normal and reverse phase TLC‐DESI‐MS methods, described in this study, can aid in their identification as they begin to emerge in later stages of development in plant tissues such as leaves, hypocotyls, and roots.     

Direct analysis of Salvia divinorum leaves for salvinorin A by thin layer chromatography and desorption electrospray ionization multi‐stage tandem mass spectrometry

Salvia divinorum is widely cultivated in the US, Mexico, Central and South America and Europe and is consumed for its ability to produce hallucinogenic effects similar to those of other scheduled hallucinogenic drugs, such as LSD. Salvinorin A (SA), a kappa opiod receptor agonist and psychoactive constituent, is found primarily in the leaves and to a lesser extent in the stems of the plant. Herein, the analysis of intact S. divinorum leaves for SA and of acetone extracts separated using thin layer chromatography (TLC) is demonstrated using desorption electrospray ionization (DESI) mass spectrometry. The detection of SA using DESI in the positive ion mode is characterized by several ions associated with the compound – [M+H]⁺, [M+NH₄]⁺, [M+Na]⁺, [2M+NH₄]⁺, and [2M+Na]⁺. Confirmation of the identity of these ions is provided through exact mass measurements using a time‐of‐flight (ToF) mass spectrometer. The presence of SA in the leaves was confirmed by multi‐stage tandem mass spectrometry (MSⁿ) of the [M+H]⁺ ion using a linear ion trap mass spectrometer. Direct analysis of the leaves revealed several species of salvinorin in addition to SA as confirmed by MSⁿ, including salvinorin B, C, D/E, and divinatorin B. Further, the results from DESI imaging of a TLC separation of a commercial leaf extract and an acetone extract of S. divinorum leaves were in concordance with the TLC/DESI‐MS results of an authentic salvinorin A standard. The present study provides an example of both the direct analysis of intact plant materials for screening illicit substances and the coupling of TLC and DESI‐MS as a simple method for the examination of natural products. Copyright © 2010 John Wiley & Sons, Ltd.     

Desorption electrospray ionization ‐ orbitrap mass spectrometry of synthetic polymers and copolymers

Desorption ElectroSpray Ionization (DESI) ‐ Orbitrap Mass Spectrometry (MS) was evaluated as a new tool for the characterization of various industrial synthetic polymers (poly(ethylene glycol), poly(propylene glycol), poly(methylmethacrylate), poly(dimethylsiloxane)) and copolymers, with masses ranging from 500 g.mol⁻¹ up to more than 20 000 g.mol⁻¹. Satisfying results in terms of signal stability and sensitivity were obtained from hydrophobic surfaces (HTC Prosolia) with a mixture water/methanol (10/90) as spray solvent in the presence of sodium salt. Taking into account the formation of multiplied charged species by DESI‐MS, a strategy based on the use of a deconvolution software followed by the automatic assignment of the ions was described allowing the rapid determination of M_n, M_w and PDI values. DESI‐Orbitrap MS results were compared to those obtained from matrix‐assisted laser desorption/ionization‐ time‐of‐flight MS and gel permeation chromatography. An application of DESI‐Orbitrap MS for the detection and identification of polymers directly from cosmetics was described. Copyright © 2012 John Wiley & Sons, Ltd.     

The First Zero‐Length Mass Spectrometry‐Cleavable Cross‐Linker for Protein Structure Analysis

Combining the properties of a zero‐length cross‐linker with cleavability by tandem mass spectrometry (MS/MS) poses great advantages for protein structure analysis using the cross‐linking/MS approach. These include a reliable, automated data analysis and the possibility to obtain short‐distance information of protein 3D‐structures. We introduce 1,1′‐carbonyldiimidazole (CDI) as an easy‐to‐use and commercially available, low‐cost reagent that ideally fulfils these features. CDI bridges primary amines and hydroxy groups in proteins with the lowest possible spacer length of one carbonyl unit (ca. 2.6 Å). The cross‐linking reaction can be conducted under physiological conditions in the pH range between 7.2 and 8. Urea and carbamate cross‐linked products are cleaved upon collisional activation during MS/MS experiments generating characteristic product ions, greatly improving the unambiguous identification of cross‐links. Our innovative analytical concept is exemplified and applied for bovine serum albumin (BSA), wild‐type tumor suppressor p53, an intrinsically disordered protein, and retinal guanylyl cyclase activating protein‐2 (GCAP‐2).     

Identification and quantification of 5,6,7,8‐tetrahydro‐2‐(2‐phenylethyl)chromones in Chinese eaglewood by HPLC with diode array detection and MS

A sensitive and reliable HPLC coupled with diode array detection and MS method was developed and validated for the first time to simultaneously identify and quantify eight characteristic 5,6,7,8‐tetrahydro‐2‐(2‐phenylethyl)chromones (THPECs) in Chinese eaglewood. Chromatographic separation was performed on a Zorbax SB C₁₈ column with a gradient of acetonitrile/0.1% formic acid/water as the mobile phase. The MS fragmentation behavior of THPECs was characterized as the successive neutral loss of two molecules of H₂O ([M+H–18–18]⁺) and then two molecules of CO ([M+H–18–18–28–28]⁺), which could be used to differentiate Chinese eaglewood from counterfeits. Validation of the developed analytical method showed good linearity, satisfactory precision, and good recovery. The established method was successfully applied to the simultaneous determination of eight THPECs in ten batches of Chinese eaglewood, which could be used as a tool for the quality control of Chinese eaglewood.     

Combination of Solid‐Phase Micro‐Extraction and Direct Analysis in Real Time‐Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for Sensitive and Rapid Analysis of 15 Phthalate Plasticizers in Beverages

A method for rapid identification and quantification of phthalate plasticizers in beverages was developed. A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Safety Improvement Act (CPSIA), European Union legislations and Chinese national standards (GB) were analyzed. By a combined solid‐phase micro‐extraction (SPME) and direct analysis in real time mass spectrometry (DART‐MS) approach, phthalates at sub‐ng·mL^?1 levels can be qualitatively and quantitatively analyzed in a short time. The use of ultrahigh‐resolving power and the accurate mass measurement capacity naturally provided by Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR‐MS) minimizes the matrix interferences and thus enables the evaluation of phthalates in a complex matrix without extensive sample handlings or preparations. The limits of quantification (LOQs) were estimated to be at 0.3–5.0 ng·mL^?1, lower than the Maximum Residue Limit (MRL) regulated by the European Union legislations (2007/19/EC) in foods, beverages, food packaging and toys (0.3–30 ng·mL^?1). This rapid and easy‐to‐use SPME‐DART‐FT‐ICR‐MS method provided a relatively high‐throughput and powerful analytical approach for quick testing and screening phthalates in beverages and water samples to ensure food safety.     

Matrix‐free thin‐layer chromatography/laser desorption ionization mass spectrometry for facile separation and identification of medicinal alkaloids

Quaternary protoberberine alkaloids belong to a pharmaceutically important class of isoquinoline alkaloids associated with bactericidal, fungicidal, insecticidal and antiviral activities. As traditional medicine gains wider acceptance, quick and robust analytical methods for the screening and analysis of plants containing these compounds attract considerable interest. Thin‐layer chromatography (TLC) combined with matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) is a powerful technique but suffers from dilution of the TLC bands resulting in decreased sensitivity and masking of signals in the low‐mass region both due to addition of matrix. This study integrates for the first time conventional silica gel TLC and laser desorption ionization mass spectrometry (LDI‐MS) thus eliminating the need for any external matrix. Successful separation of berberine (R_f = 0.56) and palmatine (R_f = 0.46) from Berberis barandana including their identification by MS are demonstrated. Furthermore, a robust electrospray ionization (ESI)‐MS method utilizing residual sample from TLC for quantification of berberine applying selected reaction monitoring and standard addition method is presented. The amount of berberine in the plant root prepared for the study was determined to be 0.70% (w/w). Copyright © 2009 John Wiley & Sons, Ltd.     

Simultaneous determination of spinosad,temephos, and piperonyl butoxide in animal‐derived foods using LC–MS/MS

Pesticides, which are used as plant protection products, can enter the food chain, and exposure to these xenobiotics can cause a wide array of health problems in humans. Therefore, the objective of the present study was to develop an analytical method for the simultaneous determination of residual spinosad (sum of spinosyn A and D), temephos and piperonyl butoxide in porcine muscle, egg, milk, eel, flatfish and shrimp (sampling period: February to June 2018) using liquid chromatography–triple quadrupole tandem mass spectrometry (LC–MS/MS). The target analytes were extracted with a combination of acidified acetonitrile and ethyl acetate and subsequently purified with original QuEChERS kits (composed of magnesium sulfate and sodium chloride) as well as n‐hexane. All analytes were separated on a reversed‐phase analytical column using a mobile phase of (A) 0.1% formic acid containing 10 mm ammonium formate in distilled water and (B) methanol. Good linearity (R² ≥ 0.980) was achieved over the tested concentration range (3.5–35 μg/kg for spinosyn A; 1.5–15 μg/kg for spinosyn D; 5–50 μg/kg for temephos and piperonyl butoxide) in matrix‐matched standard calibrations. Fortified samples at three spiking levels yielded recoveries in the range of 71–105% with relative standard deviations ≤9.2%. The applicability of the method was evaluated via evaluating samples collected from a large wholesale market located in Seoul, and none of the samples contained any of the target analytes. In conclusion, the current approach is simple, efficient and reliable and can successfully determine the residual levels of spinosad, temephos and piperonyl butoxide in complex animal‐derived food products.     

Heart‐cut nano‐LC–CZE–MS for the characterization of proteins on the intact level

Multidimensional separation techniques play an increasingly important role in separation science, especially for the analysis of complex samples such as proteins. The combination of reversed‐phase liquid chromatography in the nanoscale and CZE is especially beneficial due to their nearly orthogonal separation mechanism and well‐suited geometries/dimensions. Here, a heart‐cut nano‐LC–CZE–MS setup was developed utilizing for the first time a mechanical 4‐port valve as LC–CE interface. A model protein mixture containing four different protein species was first separated by nano LC followed by a heart‐cut transfer of individual LC peaks and subsequent CZE–MS analysis. In the CZE dimension, various glycoforms of one protein species were separated. Improved separation capabilities were achieved compared to the 1D methods, which was exemplarily shown for ribonuclease B and its different glycosylated forms. LODs in the lower μg/mL range were determined, which are considerably lower compared to traditional CZE–MS. In addition, this study represents the first application of an LC–CE–MS system for intact protein analysis. The nano‐LC–CZE–MS system is expected to be applicable to various other analytical challenges.     

Determination of prostaglandin profiles in lipopolysaccharide‐challenged guinea pig spleen

We previously reported that splenic extract from lipopolysaccharide (LPS)‐challenged guinea pigs inhibits the exaggerated febrile response of splenectomized guinea pigs, suggesting that the spleen generates an inhibitory factor. Earlier results indicate that the factor is a lipid. In an effort to identify this factor, lipid fractions, isolated from splenic extracts of control and LPS‐challenged guinea pigs, were analyzed with emphasis on identifying and quantifying prostanoids, which according to current knowledge are the likely bioactive factors. Prostaglandins have been extensively implicated in central and peripheral thermoregulation, and thus these lipids were targeted for characterization in the spleen. Analysis was done on the splenic extracts using solid‐phase extraction, analytical and preparative thin‐layer chromatography (TLC) and high‐performance liquid chromatography–mass spectrometry (HPLC‐MS/MS). Four prostaglandins (PGs, 6‐keto‐PGF_1α, PGF_2α, PGE₂ and PGD₂) were identified and quantified. Our data shows that these PG levels are doubled in LPS‐treated guinea pig spleen compared with the control group. The methods used in this investigation to characterize PG in the spleen offer significant advantages over immunoassays previously used to identify and quantify PG in the spleen and other biological tissues. These methods will be utilized in further research needed to definitively characterize the role of splenic‐derived PG in modulation of the febrile response induced by LPS. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis of the dissipation kinetics of thiophanate‐methyl and its metabolite carbendazim in apple leaves using a modified QuEChERS–UPLC–MS/MS method

As one of the main fungicides for the apple leaf disease control, thiophanate‐methyl (TM) mainly exerts its fungicidal activity in the form of its metabolite carbendazim (MBC), whose dissipation kinetics is very distinct from that of its parent but has been paid little attention. The aim of this work was to investigate the dissipation kinetics of TM and its active metabolite MBC in apple leaves using a modified QuEChERS–UPLC–MS/MS method. The results showed that TM and MBC could be quickly extracted by this modified QuEChERS procedure with recoveries of 81.7–96.5%. The method linearity was in the range of 0.01–50.0 mg kg^?1 with the quantification limit of 0.01 mg kg^?1. Then this method was applied to the analysis of fungicide dissipation kinetics in apple leaves. The results showed that the dissipation kinetics of TM for the test in 3 months can be described by a first‐order kinetics model with a DT₅₀ (dissipation half‐life) range of 5.23–6.03 days and the kinetics for MBC can be described by a first‐order absorption–dissipation model with the T_max (time needed to reach peak concentration) range of 4.78–7.09 days. These models can scientifically describe the behavior of TM and MBC in apple leaves, which provides necessary data for scientific application.     

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

Mass spectrometry (MS) applications for intact protein complexes typically require electrospray (ES) ionization and have not been achieved via direct desorption from surfaces. Desorption ES ionization (DESI) MS has however transformed the study of tissue surfaces through release and characterisation of small molecules. Motivated by the desire to screen for ligand binding to intact protein complexes we report the development of a native DESI platform. By establishing conditions that preserve non‐covalent interactions we exploit the surface to capture a rapid turnover enzyme–substrate complex and to optimise detergents for membrane protein study. We demonstrate binding of lipids and drugs to membrane proteins deposited on surfaces and selectivity from a mix of related agonists for specific binding to a GPCR. Overall therefore we introduce this native DESI platform with the potential for high‐throughput ligand screening of some of the most challenging drug targets including GPCRs.     

Direct screening of herbal blends for new synthetic cannabinoids by MALDI‐TOF MS

Since 2004, a number of herbal blends containing different synthetic compounds mimicking the pharmacological activity of cannabinoids and displaying a high toxicological potential have appeared in the market. Their availability is mainly based on the so‐called “e‐commerce”, being sold as legal alternatives to cannabis and cannabis derivatives. Although highly selective, sensitive, accurate, and quantitative methods based on GC–MS and LC–MS are available, they lack simplicity, rapidity, versatility and throughput, which are required for product monitoring. In this context, matrix‐assisted laser desorption ionization‐time of flight mass spectrometry (MALDI‐TOF MS) offers a simple and rapid operation with high throughput. Thus, the aim of the present work was to develop a MALDI‐TOF MS method for the rapid qualitative direct analysis of herbal blend preparations for synthetic cannabinoids to be used as front screening of confiscated clandestine preparations. The sample preparation was limited to herbal blend leaves finely grinding in a mortar and loading onto the MALDI plate followed by addition of 2 µl of the matrix/surfactant mixture [α‐cyano‐4‐hydroxy‐cinnamic acid/cetyltrimethylammonium bromide (CTAB)]. After drying, the sample plate was introduced into the ion source for analysis. MALDI‐TOF conditions were as follows: mass spectra were analyzed in the range m/z 150–550 by averaging the data from 50 laser shots and using an accelerating voltage of 20 kV. The described method was successfully applied to the screening of 31 commercial herbal blends, previously analyzed by GC–MS. Among the samples analyzed, 21 contained synthetic cannabinoids (namely JWH‐018, JWH‐073, JWH‐081, JWH‐250, JWH‐210, JWH‐019, and AM‐694). All the results were in agreement with GC–MS, which was used as the reference technique. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of δ‐[L‐α‐aminoadipyl]‐L‐cysteinyl‐D‐valine in cell extracts of Penicillium chrysogenum using ion pair‐RP‐UPLC‐MS/MS

δ‐[L ‐α‐Aminoadipyl]‐L ‐cysteinyl‐D ‐valine (ACV) is a key intermediate in the biosynthesis pathway of penicillins and cephalosporins. Therefore, the accurate quantification of ACV is relevant, e.g. for kinetic studies on the production of these β‐lactam antibiotics. However, accurate quantification of ACV is a challenge, because it is an active thiol compound which, upon exposure to air, can easily react with other thiol compounds to form oxidized disulfides. We have found that, during exposure to air, the oxidation of ACV occurs both in aqueous standard solutions as well as in biological samples. Qualitative and quantitative determinations of ACV and the oxidized dimer bis‐δ‐[L ‐α‐aminoadipyl]‐L ‐cysteinyl‐D ‐valine have been carried out using ion pair reversed‐phase ultra high‐performance liquid chromatography, hyphenated with tandem mass spectrometry (IP‐RP‐UPLC‐MS/MS) as the analytical platform. We show that by application of tris(2‐carboxy‐ethyl)phosphine hydrochloride (TCEP) as the reducing reagent, the total amount of ACV can be determined, while using maleimide as derivatizing reagent enables to quantify the free reduced form only.     

Extended characterization of a vacuum gas oil by offline LC‐high‐temperature comprehensive two‐dimensional gas chromatography

In a context of environmental preservation, purification and conversion of heavy petroleum cuts into high‐quality fuel becomes essential. The interest for the characterization of those very complex matrices becomes a trendy analytical challenge, when it comes to get molecular information for the optimization of industrial processes. Among new analytical techniques, high‐temperature 2‐D GC has recently proved its applicability to heavy petroleum matrices, but lacks in selectivity to separate all chemical groups. To gain resolution, heart cutting is demonstrated for LC separation of saturated, aromatic and polar compounds prior to high‐temperature 2‐D GC. Therefore, an extended global resolution was obtained, especially by a better distinction of saturated compounds. This includes iso‐paraffins and biomarker polynaphthenic structures, which are impossible to quantify with MS methods. This new way to analyze heavy petroleum fractions gives innovative opportunities for the construction of global weight distributions by carbon atoms number and by chemical families. This can right now be employed for quantitative analysis of heavy petroleum fractions and for studying conversion processes.