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AbstractLiquid chromatography (LC) and its associated techniques are essential in the pharmaceutical industry for optimizing drug formulations, ensuring product quality, and meeting regulatory standards. Thin Layer Chromatography (TLC) is widely used for rapid screening and chiral separations in early-stage development due to its simplicity and cost-effectiveness. High-Performance Liquid Chromatography (HPLC) remains the gold standard for routine analysis, offering high resolution and reproducibility for complex sample analysis and quantification of active pharmaceutical ingredients (APIs). Ultra-Performance Liquid Chromatography (UPLC) builds on HPLC, providing faster analysis, higher sensitivity, and greater efficiency, making it ideal for high-throughput testing. Supercritical Fluid Chromatography (SFC) is increasingly used for separating thermally labile and polar compounds, offering advantages in solvent usage and analysis time. This review will discuss the evolution of these chromatographic techniques and their critical role in optimizing pharmaceutical processes, ensuring product quality, and facilitating regulatory compliance throughout the drug development lifecycle. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB), caused by Fusarium spp., is a destructive disease of cereal grains. Apart from grain yield loss, a major quality concern is contamination with Fusarium-produced mycotoxins, specifically deoxynivalenol (DON). Mycotoxins accumulate in the grain, making it unfit for consumption by humans and animals. Breeding cultivars with high disease resistance and low mycotoxin contamination is a priority for wheat breeders. However, DON measurement in breeding programs is expensive and time consuming due to the lack of efficient quantification methods. In this study, we established a simple fast chromatography-tandem mass spectrometry method, which employed a one-step acetonitrile extraction protocol with a short guard column to reduce complexity, cost, and analysis time. To ensure robustness and reproducibility, the method was validated according to the U.S. Food and Drug Administration Guidance for Bioanalytical Method Validation. Furthermore, the method was applied for determination of DON in 102 wheat grain samples. Obtained results highly correlated with the conventional immunological method for all tested samples. With its ease of use, rapid sample analysis, and high sensitivity and accuracy, the method could be integrated into current FHB breeding programs to increase breeding efficiency and accelerate screening progress to identify germplasm with increased resistance to DON accumulation. [Figure: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Ultra-performance liquid chromatographic technique was applied for the first time for determination of radiochemical and chemical purity of [11C]methionine with measurement time less than 2 min. The pH and eluent strength of mobile phase were optimized to achieve a gradient elution for separation of non-radioactive impurities as well as radioactive ingredients. The developed method was validated according to the following parameters: linearity, repeatability, recovery, limit of quantitation. The novel chromatographic procedure with reduced measurement time could be uniquely applied for the quality control of [11C]methionine to considerably shorten the release time and avoid radioactivity loss of radiopharmaceutical. [ABSTRACT FROM AUTHOR]

Food analysis demands fast methods for routine control and high throughput of samples. Chromatographic separation enables simultaneous determination of numerous compounds in complex matrices, several approaches increasing separation efficiency and speed of analysis were involved. In this work, modern types of column with monolithic rod or superficially porous particles were employed and compared for determination of eight synthetic food dyes, their chromatographic performance was evaluated. During method optimization, cyano stationary phase Chromolith Performance CN 100 × 4.6 mm and Ascentis Express ES-CN 100 × 4.6 mm, 5 µm were selected for the separation of polar colorants. The separation was performed by gradient elution of acetonitrile/methanol and 2% water solution of ammonium acetate at flow rate 2.0 mL min−1. Mobile phase composition and the gradients were optimized in order to enable efficient separation on both columns. The method using fused-core particle column provided higher separation efficiency, narrow peaks of analytes resulted in increased peak capacity and shortening of analysis time. After the validation, the method was applied for analysis of coloured beers, soft drinks and candies.

The safe use of lipid-based drug delivery agents requires fast and sensitive qualitative and quantitative assessment of their cellular interactions. Many mass spectrometry (MS) based analytical platforms can achieve such task with varying capabilities. Therefore, four novel high-throughput MS-based quantitative methods were evaluated for the analysis of a small organic gene delivery agent: N,N-bis(dimethylhexadecyl)-1,3-propane-diammonium dibromide (G16-3). Analysis utilized MS instruments that detect analytes using low-resolution tandem MS (MS/MS) analysis (i.e. QTRAP or linear ion trap in this work) or high-resolution MS analysis (i.e. time of flight (ToF) or Orbitrap). Our results indicate that the validated fast chromatography (FC)-QTRAP-MS/MS, FC- LTQ-Orbitrap-MS, desorption electrospray ionization-collision-induced dissociation (CID)-MS/MS and matrix assisted laser desorption ionization-ToF/ToF-MS MS methods were superior in the area of method development and sample analysis time to a previously developed liquid chromatography (LC)-CID-MS/MS. To our knowledge, this is the first evaluation of the abilities of five MS-based quantitative methods that target a single pharmaceutical analyte. Our findings indicate that, in comparison to conventional LC-CID-MS/MS, the new MS-based methods resulted in a (1) substantial reduction in the analysis time, (2) reduction in the time required for method development and (3) production of either superior or comparable quantitative data. The four new high-throughput MS methods, therefore, were faster, more efficient and less expensive than a conventional LC-CID-MS/MS for the quantification of the G16-3 analyte within tissue culture. When applied to cellular lysate, no significant change in the concentration of G16-3 gemini surfactant within PAM212 cells was observed between 5 and 53 h, suggesting the absence of any metabolism/excretion from PAM212 cells. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] SFC speed-resolution properties of sub-2μm particles are given under adiabatic conditions. [•] The effect of the organic modifier content on column performance was theoretically studied. [•] At low pressure drop, increasing methanol content decreases efficiency and analysis speed. [•] At high pressure drop, increasing methanol content does not affect the maximum efficiency. [•] At high pressure drop, increasing methanol content minimizes the loss of analysis speed. [ABSTRACT FROM AUTHOR]

Background: A rapid liquid chromatography–tandem mass spectrometric (LC–MS/MS) method was developed and validated for the quantification of reactive oxygen species (ROS) derived free oxysterols and cholesterol in human plasma and atherosclerotic plaque. Method: In vitro autoxidation of cholesterol during sample pretreatment was avoided by applying only one protein precipitation and re-concentration step using 80μl plasma. For preparation of 10mg atherosclerotic plaques an additional liquid–liquid extraction was included. Free 7-keto-, 7-α/ß-hydroxy-, 5,6-α-epoxy-, 5,6-β-epoxycholesterol, cholestane-3ß,5α,6ß-triol and cholesterol were separated within 7min on a monolithic column. An API 4000 tandem mass spectrometer was applied in positive ionization mode using atmospheric pressure chemical ionization. Results: The detection limit was 0.1ng/ml and the linearity ranged from 0.5 to 0.75 to 2000ng/ml for the oxysterols and from 50 to 1000μg/ml for cholesterol. Recovery was between 80.9 and 107.9%. Between-run imprecision ranged from 7.9 to 11.7%. Analysis of plasma samples from additional 50 middle-aged volunteers revealed a large inter-individual variability (e.g. 7-ketocholesterol 2.63-30.47ng/ml). Oxysterol concentrations normalized to cholesterol were about 43 times higher in carotid plaque compared to plasma (n=5). Conclusion: This rapid LC–MS/MS method enables reliable quantification focused on especially ROS-derived oxysterols in human plasma and atherosclerotic plaque samples under high-throughput conditions. [ABSTRACT FROM AUTHOR]

Highlights: [•] The concept of Poppe plot is extended and used to compare column performance in SFC and HPLC. [•] The columns were assumed to be radially homogeneous and to operate under adiabatic conditions. [•] The dispersion process in adjacent column slices is assumed to be independent. [•] For axial column non-uniformity, the linear addition rule applies to the time variance only. [•] In RPLC and SFC, columns of core–shell particles outperform those of fully porous particles. [Copyright &y& Elsevier]

Abstract: The sources of band broadening in fast gradient elution chromatography include the contributions of the tubings placed upstream the column, the isocratic migration of the sample that takes place in the column until the moment when the front of the gradient catches up with it, dispersion and mass transfer resistance during band migration under gradient elution to the column outlet, and dispersion in the tubings downstream the column to the detector. The measurements of all these contributions is meticulously described, analyzed, and applied to assess the kinetic performance of monolithic columns of the second generation (KGaA Merck) in gradient elution, at the highest possible speed at which they can be operated (t 0=25s at P =200bar). These results are compared to those provided by several 4.6mm × 100mm columns packed with sub-3μm core–shell particles (Kinetex, Phenomenex and Halo, Advanced Material Technologies) and by a 2.1mm × 100mm column packed with fully porous 1.7μm BEH particles (Waters). A RPLC checkout sample (Agilent) containing nine alkanophenones (molecular weights between 120 and 204g/mol) was used for this purpose. The mobile phase was a mixture of acetonitrile and water and the instrument, an optimized version of the 1290 Infinity HPLC system (Agilent). The results show that the overall peak capacity provided by this second generation of monolithic columns is nearly 30% smaller than that provided by commercial columns packed with sub-3 μm core–shell particles and 20% smaller than that provided by a narrow-bore column packed with sub-2μm fully porous particles. After isolating the sole band broadening contribution due to the gradient migration of the analytes along the columns, the BEH column proved to provide the highest resolution power (apparent average plate height, of 2μm), followed by the 2.6μm Kinetex particles (3.0μm), the Halo particles (3.2μm), and the second generation of 4.6mm I.D. monolithic columns (6.5μm). This work demonstrates that analysts have an urgent need for very high pressure liquid chromatographs having smaller dwell and extra-column volumes that those of the currently available instruments. The gradient elution peak capacity provided by the modern, narrow-diameter columns, which are short and highly efficient (plate heights of 3–4μm), is barely half what the column alone could produce if it were fitted to a perfect instrument. The other half of the peak capacity is just wasted by the instrument. [Copyright &y& Elsevier]

Quantitative and qualitative high-resolution (HR) dependent and independent acquisition schemes on a QqTOF MS (with resolving power 20,000-40,000) were investigated for the analysis of pharmaceutical compounds in biological fluids. High-resolution selected reaction monitoring (HR-SRM) was found to be linear over three orders of magnitude for quantitative analysis of paracetamol in human plasma, offering a real alternative to triple quadrupole LC-SRM/MS. Metabolic stability of talinolol in microsomes was characterized by use of three different acquisition schemes: (i) information-dependent acquisition (IDA) with a TOF MS experiment as survey scan and product-ion scan as dependent scan; (ii) MS by collecting TOF mass spectra with and without fragmentation by alternating the collision energy of the collision cell between a low (i.e., 10 eV) and high setting (i.e., 40 eV); and (iii) a novel independent acquisition mode referred to as 'sequential window acquisition of all theoretical fragment-ion spectra' (SWATH) or 'global precursor ions scan mode' (GPS) in which sequential precursor ions windows (typically 20 u) are used to collect the same spectrum precursor and fragment ions using a collision energy range. SWATH or GPS was found to be superior to IDA or MS in combination with UHPLC for qualitative analysis but requires a rapidly acquiring mass spectrometer. Finally, the GPS concept was used for QUAL/QUAN analysis (i.e. integration of qualitative and quantitative analysis) of bosentan and its metabolites in urine over a concentration range from 5 to 2,500 ng mL. [ABSTRACT FROM AUTHOR]

Abstract: The gradient elution performance of narrow-bore 2.3mm×50mm (N733) and wider bore 3.2mm×50mm (N648 and N655) prototype silica monolithic columns was investigated and compared to the performance of commercially available columns packed with sub-2μm fully porous particles (2.1mm×50mm, 1.7μm BEH-C18, Waters) and sub-3μm superficially porous particles (2.1mm×50mm, 2.7μm Halo-ES-Peptide-C18 (AMT), 1.7 and 2.6μm Kinetex-C18, Phenomenex). Results show that the two wide monolithic columns show peak capacities similar to the one measured for the Kinetex column. In contrast, the narrow-bore monolithic column delivers a lower performance (−30%) than the BEH, the Halo and the Kinetex columns. This work stresses out the importance of reducing the extra-column band broadening contribution of HPLC instruments when short 2.1mm I.D. columns are used. The part of the instrument contribution originating downstream the column is important for all compounds; the one originating upstream the column is significant only for weakly retained compounds. [Copyright &y& Elsevier]

Abstract: A fast liquid chromatographic/tandem mass spectrometric method was developed for the simultaneous determination in human urine of seventeen benzodiazepines, four relevant metabolites together plus zolpidem and zopiclone. The sample preparation, optimized to take into account the matrix effect, was based on enzymatic hydrolysis and liquid–liquid extraction. The separation of the twenty-three analytes was achieved in less than eight minutes. The whole methodology was fully validated according to UNI EN ISO/IEC 17025:2005 rules and 2006 SOFT/AAFS guidelines. Selectivity, linearity range, identification (LOD) and quantitation (LOQ) limits, precision, accuracy and recovery were evaluated. For all the species the signal/concentration linearity was satisfactory in the 50–1000ng/mL concentration range. The limits of detection ranged from 0.5 to 30ng/mL and LOQs from 1.7 to 100.0ng/mL. Precisions were in the ranges 5.0–11.8%, 1.5–11.0% and 1.1–4.4% for low (100ng/mL), medium (300ng/mL) and high (1000ng/mL) concentration, respectively. The accuracy, expressed as bias% was within ±25% for all the analytes. The recovery values, evaluated at 300ng/mL concentration, ranged from 56.2% to 98.8%. The present method for the determination of several benzodiazepines, zolpidem and zopiclone in human urine proved to be simple, fast, specific and sensitive. The quantification by LC–MS/MS was successfully applied to 329 forensic cases among driving re-licensing, car accidents and alleged sexual violence cases. [Copyright &y& Elsevier]

Abstract: A new methodology using second-order calibration based on PARAllel FACtor analysis 2 (PARAFAC2) is developed for fast quantification of aflatoxins B1, B2, G1 and G2 in pistachio samples by liquid chromatography with diode array detection (LC-DAD). Solvent and solid phase extractions were used for sample preparation steps. In this work, a gradient elution programme was optimised to make co-elutions between analytes and also to shorten the analysis time. Prediction was made on synthetic and real validation samples with a mixture calibration design. Special circumstances such as overlapping of analytes, the lack of spectral selectivity and also the lack of trilinearity, have been compensated with “mathematic separation” through PARAFAC2 modelling. The results showed an acceptable performance of PARAFAC2 for resolution and quantification of all analytes in a single array exploiting the second-order advantage. With the proposed method, the chromatographic run time and also the time for data analysis were reduced significantly. [Copyright &y& Elsevier]

Abstract: In the pharmaceutical industry fast and efficient separation techniques play an increasing role among analytical methods because the samples to be investigated grow both in complexity and number, and there is an increasing time pressure to complete the analysis. Reducing the analysis time without decreasing the efficiency is possible using higher pressures, elevated temperatures, smaller particle sizes, or a combination of these approaches. Recently developed chromatographic techniques such as the UHPLC (ultra high performance liquid chromatography) and HTLC (high temperature liquid chromatography) are highly promising in meeting these demands. In this study, high temperature liquid chromatography (HTLC) with a zirconia-based column and temperatures elevated up to 150°C was used. We investigated the chromatographic behaviour of a steroid active pharmaceutical ingredient (levonorgestrel) and its structurally related impurities as model compounds. The effect of the temperature in the range of 50–150°C and the flow-rate in the range of 0.5–3.0ml/min, and using methanol as an organic modifier, were studied for optimisation of the separation method. [Copyright &y& Elsevier]

Abstract: New hyphenated technique for the extraction and determination of isoflavones in sea and freshwater algae and cyanobacteria was developed. The method consists of sonication sample pretreatment, extraction by supercritical CO2 modified by 3% (v/v) of MeOH/H2O mixture (9:1, v/v) at 35MPa and 40°C for 60min, fast chromatography analysis by the means of Agilent 1200 Series Rapid Resolution and MS/MS determination. Agilent 1200 Series RRLC was used with Zorbax SB-CN chromatographic column (100mm×2.1mm, particle size 3.5μm), 3μl injection volume, mobile phase consisting of 0.2% (v/v) acetic acid in water (solvent A) and acetonitrile (solvent B) and used with linear gradient (30% B at 0min, from 0min to 3min up to 50% B, from 3 to 6min up to 80% B and from 6 to 10min down to 30% B). The flow-rate was 0.4mL/min, column oven temperature 35°C. MS detector Agilent Technologies 6460 Triple quadrupole LC/MS with Agilent Jet Stream was used in a negative ESI mode under following conditions: gas temperature 350°C, gas flow 13L/min, nebulizer gas pressure 50psi, sheath gas temperature 400°C, sheath gas flow 12L/min, capillary voltage was 4kV. Samples were analysed in the multiple reaction monitoring (MRM) mode. Eight isoflavone compounds were found for the first time in seven real samples of sea algae and in three control samples of freshwater algae and cyanobacteria. Usual optimisation study of extraction parameters was performed. Pressure and temperature optima for algae matrix are different from those obtained sooner for other matrices for most of the analytes, but the results of modifier optimisation study are in good accordance with those obtained sooner for spiked samples and red clover matrix. It seems that matrix has very small or no effect on the modifier selection. Two different approaches of sonication pretreatment were tested: sonication bath and the thorn instrument. In longer extraction time experiments, thorn sonication was more efficient and recovery of following supercritical fluid extraction was higher. [Copyright &y& Elsevier]

Abstract: A novel fast and sensitive method has been developed for the specific simultaneous determination of polysorbate 20 (Tween 20) and unbound polyethylene-glycol (PEG) from liquid formulations in the presence of proteins and excipients. The quantitative determination is based on a fast liquid chromatographic (HPLC) separation and condensation nucleation light scattering detection (CNLSD or NQAD™). The method uses a Kinetex core–shell column (100mm×3mm, 2.6μm) and methanol–water–trifluoroacetic acid mobile phase. The rapid HPLC-CNLSD method presented here is suitable for quantifying polysorbate 20 in the range of 10–60μg/ml and unbound PEG in the range of 2–40μg/ml in protein solutions within good manufacturing practices (GMP) of the pharmaceutical industry. [Copyright &y& Elsevier]

Abstract: A fast and sensitive method has been developed for the specific determination of Polysorbate 80 (Tween 80) in liquid formulations in the presence of proteins and excipients. The quantitative determination is based on a fast liquid chromatographic (HPLC) separation and charged aerosol detection (CAD). The method was validated using a Poroshell 300SB-C18 column packed with 5μm shell particles (75mm×2.1mm) and acetonitrile–methanol–water–trifluoroacetic acid mobile phase at a flow rate of 0.65ml/min. The rapid LC–CAD method is suitable for quantifying Polysorbate 80 in the range of 10–60μg/ml in protein solutions within good manufacturing practices (GMPs) of the pharmaceutical industry. [Copyright &y& Elsevier]

Abstract: We review recent approaches for greening analytical separation technologies. Whereas conventional analytical separation technologies produce as much as 50mL of waste per analysis, greener options considerably reduce the amount of waste generated per analysis, ranging from simply adoptable small-particle stationary-phase technologies and reduced column diameters to more specialized technologies [e.g., ultra-high-pressure liquid chromatography (UHPLC), supercritical-fluid chromatography (SFC) and microscale or nanoscale HPLC]. In addition, greener eluents and chromatography conditions can also be used, including substitution of ethanol for acetonitrile in reversed-phase HPLC and the use of water alone as an eluent at elevated temperatures. We describe the merits of these emerging technologies, and discuss the factors influencing the decision to move from conventional analytical separation methodologies to greener alternatives. [ABSTRACT FROM AUTHOR]

Abstract: The present study describes the use of short columns to speed up LC–MS quantification in MS binding assays. The concept of MS binding assays follows closely the principle of traditional radioligand binding but uses MS for the quantification of bound marker thus eliminating the need for a radiolabelled ligand. The general strategy of increasing the throughput of this type of binding assay by the use of short columns is exemplified for NO 711 binding addressing GAT1, the most prevalent GABA transporter in the CNS. Employing short RP-18 columns with the dimension of 20mm×2mm and 10mm×2mm at flow rates up to 1000μL/min in an isocratic mode retention times of 8–9s and chromatographic cycle times of 18s could be achieved. Based on the internal standard [2H10]NO 711 fast chromatography methods were developed for four different columns that enabled quantification of NO 711 in a range from 50pM up to 5nM directly out of reconstituted matrix samples without further sample preparation. A validation of the established methods with respect to linearity, intra- and inter-batch accuracy and precision showed that the requirements according to the FDA guideline for bioanalytical methods are met. Furthermore the established short column methods were applied to the quantification of NO 711 in saturation experiments. The results obtained (i.e., K d- and B max-values) were almost identical as compared to those determined employing standard column dimension (55mm×2mm). [Copyright &y& Elsevier]

Abstract: Macroporous cellulose beads (MCB) used as anion exchangers were successfully prepared from cellulose solution in ionic liquid by double emulsification followed by cross-linking and modification with diethylaminoethyl. The pore structure and properties of the MCB were investigated and the results were compared with homogeneous cellulose beads (HCB). The MCB in size of about 71μm is characterized by two sets of pores, i.e., diffusion pores (10–20nm) and macropores (800–2000nm), determined by mercury porosimeter. In addition, the bed permeability and effective porosity for BSA of MCB-packed column are 58% and 25% higher than those of HCB-packed column, respectively. The adsorption properties of MCB were evaluated, and compared with HCB and commercial absorbent (Sepharose 6 Fast Flow, CSFF). It is found that the pore diffusivity of BSA in MCB is over 7.9 times higher than HCB, and 6.7 times higher than CSFF, respectively. While the equilibrium adsorption capacity (q m ) of BSA on MCB is obviously lower than that on HCB and CSFF, the dynamic binding capacity (DBC) on MCB at 10% breakthrough reaches 47.7mg/mL, higher than HCB (40.3mg/mL) and CSFF (46.2mg/mL) at flow rate of 360cm/h. In addition, the MCB-packed column showed better column efficiency over the HCB packed one. Therefore, we demonstrated that the MCB possessed more advantages than other ones, like HCB and CSFF, and was expected as an ideal material for fast chromatography. [Copyright &y& Elsevier]

Abstract: Increasing the separating efficiency enhances the separation power. The most popular solution for improving chromatographic performance is to employ columns packed with small particle diameters (i.e., sub-2μm particles) to induce a simultaneous improvement in efficiency, optimal velocity and mass transfer, albeit the cost of pressure. In this study a systematic evaluation of the possibilities and limitations of the separations obtained with 5cm long narrow bore columns packed with 1.5–3.0μm particles is presented. Several commercially available different sub-3μm and sub-2μm packed columns were evaluated by using van Deemter, Knox and kinetic plots. Theoretical Poppe plots were constructed for each column to compare their kinetic performance. Data are presented on different polar neutral real life analytes, to show that the separation time is not obviously shorter if the particle size is reduced. Comparison of low-molecular weight compounds (one steroid and one non-steroid hormone, with molecular weights lower than 500) and a high-molecular weight one (MW∼1000) was conducted. Same efficiency can be achieved with columns packed with 1.9–2.1μm particles as with smaller particles. The column packed with 3μm particles had the lowest reduced plate height minimum (h =2.2) while the column with the smallest particles (1.5μm) gave the highest reduced plate height minimum (h ∼3.0). According to this study, the theoretically expected efficiency of very fine particles (diameter <2μm) used in practice today is compromised. Investigation of this phenomenon is presented. [Copyright &y& Elsevier]

Abstract: In this paper, three different HPLC methods for the quantification of thalidomide in tablets were developed and compared. The comparison of a conventional method at 30°C with two high-temperature methods at 180°C showed equal results. Using high-temperature HPLC (HT-HPLC), faster analysis times could be achieved. We have also focused on analyte stability and could show that the stationary phase has a pronounced effect on the on-column degradation of thalidomide at high temperatures. Virtually no degradation occurs if a polystyrene divinylbenzene column is used, whereas thalidomide is completely degraded at 180°C when a carbon clad zirconium dioxide column is used. [Copyright &y& Elsevier]

A rapid-resolution HPLC/UV-VIS DAD separation method (which takes <1 min) for the determination and identification of genistin, genistein, daidzein, daidzin, glycitin, glycitein, ononin, formononetin, sissotrin and biochanin A in fmol quantities in submicroliter sample volumes was optimized. A linear gradient elution (0 min 22% B, 1.0 min 80% B, 1.4 min 100% B, 1.8 min 22% B) using a mobile phase containing 0.2 % (v/v) acetic acid (solvent A) and methanol (solvent B) was applied on a Zorbax SB C18 column (1.8 μm particle size) at 80 °C. The method was verified using samples of bits of soy and methanolic extracts from Trifolium pratense, Iresine herbstii and Ononis spinosa plants. Pseudobaptigenin glucoside, irilone, prunetin, texasin, tlatlancuayin and other isoflavones, in addition to aglycones of isoflavones and their β-glucosides and malonyl and acetyl derivatives, were identified by UV-VIS DAD and electrospray mass spectrometric (ESI-MS) detection in the extracts. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Chromatographic behavior of a series of N-methylated tetra and octapeptides on a reversed-phase sorbent was studied considering the information obtained on these compounds by NMR spectroscopy. The modified tetrapeptides were derived from GFFY-NH2, GFFF-NH2 and GFFH-NH2 primary structures by N-methylation at various peptide bond positions. Similarly, the N-methylated octapeptides were based on TPK(Pac)T C-terminally elongated forms of GFFY and GFFF. It was found that many studied N-methylated peptides provide broad peaks as a consequence of cis/trans isomerism of the R1CON(CH3)R2 peptide bond. The extent of the peak spreading depends on the following important factors: the nature of the surrounding amino acid residues, the location of the modified peptide bond within the peptide chain, temperature, and mobile phase flow-rate. All these aspects were critically evaluated. Nearly complete separation of the individual conformers of GF(NMe)FY-NH2 was obtained applying fast chromatography on short column packed with 20–30 μm reversed-phase sorbent. [Copyright &y& Elsevier]

Abstract: Multivariate curve resolution-alternating least squares (MCR-ALS) is shown to be a powerful tool to resolve coelution problems in liquid chromatograpy–mass spectrometry (LC–MS) in scan mode. This investigation was performed using two types of LC columns, one traditional LC column of 25cm length with a slow gradient and a shorter LC column of 7.5cm with a rapid gradient which allowed much faster analysis and save of reagents and solvents. Mixtures of multiple biocide compounds were simultaneously analyzed in standard mixtures and in environmental samples (sediment and wastewater samples) with little sample pretreatment. Using the more traditional LC 25cm column, all biocide compounds were properly resolved by MCR-ALS and quantitatively analyzed with estimated errors always below 20%. When fast chromatography (LC column of 7.5cm) was used, MCR-ALS resolution of the more strongly coeluted compounds was also achieved but limitations were found in their simultaneous quantitative determination, specially for environmental samples. [Copyright &y& Elsevier]

Food analysis demands fast methods for routine control and high throughput of samples. Chromatographic separation enables simultaneous determination of numerous compounds in complex matrices, several approaches increasing separation efficiency and speed of analysis were involved. In this work, modern types of column with monolithic rod or superficially porous particles were employed and compared for determination of eight synthetic food dyes, their chromatographic performance was evaluated. During method optimization, cyano stationary phase Chromolith Performance CN 100 × 4.6 mm and Ascentis Express ES-CN 100 × 4.6 mm, 5 µm were selected for the separation of polar colorants. The separation was performed by gradient elution of acetonitrile/methanol and 2% water solution of ammonium acetate at flow rate 2.0 mL min−1. Mobile phase composition and the gradients were optimized in order to enable efficient separation on both columns. The method using fused-core particle column provided higher separation efficiency, narrow peaks of analytes resulted in increased peak capacity and shortening of analysis time. After the validation, the method was applied for analysis of coloured beers, soft drinks and candies. [ABSTRACT FROM AUTHOR]