Traditional High-performance Liquid Chromatography Research Articles

G-Quadruplex DNAzyme-Based Biocatalysis Combined with an Intelligent Electromagnetic-Actuated Microfluidic Chip for Tetracycline Detection.

In this study, we present an intelligent electromagnetic-actuated microfluidic chip integrated with a G-quadruplex DNAzyme-based biocatalysis platform for rapid and sensitive tetracycline (TC) detection. In this sensing system, TC significantly quenches fluorescent magnetic carbon dots (M-CDs) via the internal filtration effect and dynamic quenching (the excitation and emission wavelength at 350 and 440 nm, respectively). Then, the G-quadruplex on the M-CDs-Aptamer is exposed and bound with hemin to form hemin-G-quadruplex DNAzyme, catalyzing the conversion of 3,3',5,5'-tetramethylbenzidine to produce blue color. This enables the fluorescence/colorimetric detection of TC. Importantly, an automatic electromagnet-integrated microfluidic chip was designed to control the shuttling of magnetic materials in each function slot according to a programmed sequence. Under the optimal conditions, the detection limits of TC for fluorescence and colorimetric methods were 11 and 43 μmol/L, respectively. The detection results for tilapia (Oreochromis nilotica) were comparable to those of traditional high-performance liquid chromatography. This platform offers excellent performance for TC determination and potential for portable, intelligent detection of trace pollutants in food and the environment.

Sampling-free investigation of microbial carbon source preferences on renewable feedstocks via online monitoring of oxygen transfer rate.

The transition towards sustainable bioprocesses requires renewable feedstocks to reduce dependency on finite resources. While plant-based feedstocks offer significant potential, their complex composition poses new challenges. The microorganisms often exhibit polyauxic growth when presented with multiple carbon sources simultaneously, consuming them in a distinct order according to their carbon source preferences. The traditional investigation of polyauxic growth involves laborious sampling and offline analysis, hindering high-throughput screenings. This study introduces an efficient method for identifying carbon source consumption and their order of metabolization by various microorganisms using the respiration activity monitoring system (RAMOS) in shake flasks. As aerobic carbon metabolization and oxygen consumption are strictly correlated, the characteristic phases of polyauxic growth are visible in the oxygen transfer rate (OTR) and can be assigned to the respective carbon sources. An extended 16-flask RAMOS enables real-time monitoring of microbial respiration on up to seven carbon sources and one reference cultivation simultaneously, thus providing crucial insights into their metabolization without extensive sampling and offline analysis. The method's accuracy was validated against traditional high-performance liquid chromatography (HPLC). Its applicability to both fast-growing Escherichia coli (investigated carbon sources: glucose, arabinose, sorbitol, xylose, and glycerol) and slow-growing Ustilago trichophora (glucose, glycerol, xylose, sorbitol, rhamnose, galacturonic acid, and lactic acid) was demonstrated. Additionally, it was successfully applied to the plant-based second-generation feedstock corn leaf hydrolysate, revealing the bioavailability of the included carbon sources (glucose, sucrose, arabinose, xylose, and galactose) and their order of metabolization by Ustilago maydis.

A biosensor based on MWCNTs-BSA and TiO2-Laccase nanocomposite modified glassy carbon electrode for sensitive detection of luteolin in traditional Chinese Medicine

Luteolin (Lut) is an extractable natural flavonoid compound found in various herbs, vegetables, and fruits, and has become an increasingly important focus of in vivo and in vitro studies. These investigations confirmed that luteolin possesses antioxidant, antidiabetic, and anticancer properties, and has significant medicinal value. In this study, a biosensor was developed using a nanocomposite of Multi walled carbon nanotubes (MWCNTs), Bovine Serum Albumin (BSA), Laccase (Lac), TiO2, and Chitosan (Chi) to modify a glassy carbon electrode (GCE) for the detection of luteolin. The modified materials and electrodes were analyzed using scanning electron microscopy (SEM), cyclic voltammogram (CV), and electrochemical impedance spectroscopy (EIS). The square wave voltammetry (SWV) study indicated that the linear ranges were from 80 nM to 1 μM and from 1 to 6 μM, respectively, and the detection limit of luteolin was as low as 11 nM. The sensor exhibited excellent sensitivity and selectivity even in the presence of potential interfering substances. This proposed biosensor was successfully utilized to detect luteolin in the Traditional Chinese Medicine of Scutellaria Barbata and Dandelion. It demonstrated comparable good accuracy to traditional high performance liquid chromatography results. Therefore, this biosensor plays an important role in detecting the content of luteolin.

Detection of Hemoglobin Constant Spring: A Comparison of Capillary Electrophoresis Versus High-Performance Liquid Chromatography.

In Malaysia, Hemoglobin Constant Spring (Hb CS) is the most common non-deletional α-thalassemia, caused by a mutation at the termination codon of the α2-globin gene (TAA>CAA). Detection typically involves identifying an abnormal peak at zone 2 on capillary electrophoresis (CE) or a small peak at the C-window on high-performance liquid chromatography (HPLC), indicative of Hb CS. This study aimed to investigate the correlation between HPLC and CE in detecting Hb CS, evaluating their respective diagnostic accuracies and limitations. A cross-sectional study was conducted at Hospital Sultanah Nur Zahirah involving secondary school students (Form 4) from Terengganu who participated in a thalassemia screening program conducted by the Ministry of Health (MOH) from January 2019 to December 2022. Blood samples from subjects showing a positive peak in zone 2 of CE and a small peak at the C-window of HPLC were selected. Molecular studies of these samples were performed to confirm the presence of Hb CS. For the statistical analysis, the Pearson correlation coefficient was employed to assess the relationship between CEand HPLCresults. Hb CS was confirmed in all samples by molecular studies, revealing 92.3% heterozygous, 7.2% compound heterozygous, and 0.5% homozygous cases. CE detected 92.3% of heterozygous Hb CS cases, while HPLC detected only 48.2%. For compound heterozygous Hb CS, CE detected 100%, whereas HPLC detected 89.3%. Both homozygous cases were detected by CE and HPLC. The Pearson correlation coefficient test showed a significant linear relationship (p<0.001) between CE's zone 2 peak values and HPLC's C-window peaks (n=389). Conclusion: These findings highlight the efficacy of CE as a reliable method for Hb CS detection, suggesting its potential superiority over traditional HPLC in clinical settings.

Novel portable photoelectrochemical sensor based on CdS/Au/TiO2 nanotube arrays for sensitive, non-invasive, and instantaneous uric acid detection in saliva

Uric acid (UA) monitoring is the most effective method for diagnosis and treatment of gout, hyperuricemia, hypertension, and other diseases. However, challenges remain regarding detection efficiency and rapid on-site detection. Here, we first synthesized a CdS/Au/TiO2-NTAs Z-scheme heterojunction material using a titanium dioxide nanotube array (TiO2-NTAs) as the substrate and modified with gold nanoparticles (Au) and cadmium sulfide particles (CdS). This material achieves bandgap alignment to generate a large number of electron-hole pairs under illumination. Then, using CdS/Au/TiO2-NTAs as the working electrode and molecularly imprinted polymers (MIP) as the recognition unit, we constructed a portable photoelectrochemical (PEC) sensor for non-invasive instant detection of UA concentration in human saliva, which has unique advantages in the field of high-sensitivity PEC instant detection. The portable MIP-PEC sensor achieves a linear range of 0.01–50 μM and a detection limit as low as 5.07 nM (S/N = 3). At the same time, the portable MIP-PEC sensor exhibits excellent sensitivity, specificity as well as stability, and shows no statistically significant difference compared to traditional high-performance liquid chromatography (HPLC) in practical sample detection. Compared to traditional PEC modes, this work demonstrates a novel and universal method for high-sensitivity instant detection in the field of PEC.

Sensitive detection of trilobatin in tea beverages based on hydroxy-functionalized Ag@COF SERS substrate

As a dihydrochalcone natural sweetener extracted from Lithocarpus litseifolius, trilobatin is an emerging functional sweetener in the international arena in recent years and is gaining attention in the food industry. The detection of trilobatin has also gradually received the attention of researchers, however, the detection means for trilobatin still remain in the traditional high performance liquid chromatography (HPLC) and other traditional methods, which are costly and have a large detection range. In this work, a method based on the principle of surface-enhanced Raman (SERS) using a composite substrate of silver nanoparticles (Ag NPs) and covalent organic frameworks (COFs) materials is proposed for the detection of trilobatin in tea beverages. After Gaussian simulation and a series of spectral analysis methods for validation, the functionalized SERS substrates contain abundant hydroxyl groups on the surface, which can be combined with trilobatin through hydrogen bonding and greatly enhance the Raman signal of trilobatin. The specific detection of trilobatin in tea beverages has been realized and the problem of weak SERS signal of trilobatin in liquid environment has been solved. The limit of detection (LOD) of trilobatin in tea beverage was 2.8 nM, and the correlation coefficient (R2) was 0.995. The recoveries were in the range of 100.6∼106.0% with the RSD of 1.756∼4.921%. In conclusion, the experimental method is highly sensitive and specific, and can realize the nondestructive detection of trilobatin in samples with high practical value.

Direct analysis of tobacco specific nitrosamines in tobacco products using a molecularly imprinted polymer-packed column.

Tobacco specific nitrosamines (TSNAs) are highly carcinogenic by-products in tobacco samples, and their presence is regulated by the Food and Drug Administration. Molecularly imprinted polymers (MIPs) are synthetic polymers that have been "imprinted" with a template analyte in a co-polymer system, and can selectively extract analytes from complex matrices. MIPs can be incorporated into online systems, replacing traditional high performance liquid chromatography (HPLC) columns. MIP material specific for TSNAs was packed into an empty HPLC column using a slurry packing technique. The developed method with the MIP-packed HPLC column was validated on a LC-MS/MS system for the quantitation of N-nitrosonornicotine (NNN) and 4- (methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in commercial tobacco products. The method was linear over .1-10 ng/ml (.4-10 μg/g) for NNN and NNK. The limit of detection (LOD) was .03 ng/ml (12 μg/g) and the limit of quantitation (LOQ), .1 ng/ml (.4 μg/g). All column uniformity parameters with the exception of theoretical plate number were within the accepted criteria (% RSD values <15%). Theoretical plate number was <250, owing to the large (50 μm) sized MIP particles. Twenty-six tobacco products contained TSNA concentrations that were consistent with reported literature values. The TSNA-MIP based HPLC column effectively replaced a traditional reverse phase HPLC column, and was used for the direct analysis of nicotine and tobacco products without extensive sample preparation prior to instrumental analysis.

Quantitative 1H NMR with global spectral deconvolution approach for the determination of gamma-aminobutyric acid in Chinese yam (Dioscorea polystachya Turczaninow).

We developed a quantitative proton nuclear magnetic resonance (qNMR) with global spectral deconvolution (GSD) method to determine the gamma-aminobutyric acid content in Chinese yam with the proton signal at δH 2.30. Trimethylsilyl-2,2,3,3-tetradeuteropropionic acid sodium salt was set as the internal standard. The method was validated and showed admissible stability, repeatability, and precision. Compared to the traditional high-performance liquid chromatography method, this method did not involve tedious pre-treatment and expensive standard. Compared to ordinary qNMR, GSD algorithm could effectively remove the effect of noise, baseline distortions and signal overlapping. Overall, qNMR with GSD method is a rapid, simple and reliable method to quantitatively determine functional metabolites even overlapped with other compounds in herbs or foods.

A novel fluorescent sensor based on a magnetic covalent organic framework-supported, carbon dot-embedded molecularly imprinted composite for the specific optosensing of bisphenol A in foods

An efficient one-pot strategy for the synthesis of a bisphenol A (BPA) fluorescent sensor based on a magnetic covalent organic framework-supported, carbon dot-embedded molecularly imprinted composite (named MCOF@CD@MIP) is reported for the first time in this work. Herein, MCOFs were prepared via the simple in-situ growth of COF crystals on Fe3O4 nanoparticles and acted as supports to provide a large surface area for CD-embedded MIP layer deposition through a room temperature sol-gel molecular imprinting process. The fabricated MCOF@CD@MIP integrated the useful magnetic properties of Fe3O4, the signal transduction function of CDs, the signal amplification effect derived from the COFs and MIP, and the specific recognition behavior of MIP toward template molecule BPA. Based on the fluorescence quenching behavior of BPA for the MCOF@CD@MIP, a highly sensitive and selective fluorescent MCOF@CD@MIP sensor was developed over the concentration range of 25–3000 μg L-1 with a low detection limit (12 μg L-1). Furthermore, the MCOF@CD@MIP sensor was employed to detect BPA in canned goods and boxed drinks with satisfactory results, which agreed well with those obtained by the traditional high performance liquid chromatography (HPLC) method, demonstrating the good reliability, accuracy and practicality of our constructed sensor.

Activatable NIR-II Fluorescent Nanoprobe for Rapid Detection and Imaging of Methylglyoxal Facilitated by the Local Nonpolar Microenvironment.

Closely related to multiple chronic inflammation, especially type-2 diabetes (T2D), methylglyoxal (MGO) may be a potential key to visualize disease progression and treatment effects. On the other hand, lack of convenient and fast analytical methods cannot afford accurate MGO quantitative evaluation. In this work, an activatable second near-infrared region (NIR-II) fluorescent probe TDTCD was synthesized and its reaction mechanism with MGO was discussed. The desired NIR-II product preferred response solvents with small polarity. A novel activatable nanoprobe, MG-SLNP, for MGO was then constructed based on rational packaging to provide a local nonpolar microenvironment. The hydrophobic core of nanoparticles not only successfully improved the stability and water solubility but also greatly promoted the response rate while reacting with MGO. The comparison between NIR-II fluorescence and the traditional high-performance liquid chromatography method for T2D blood samples was discussed. A high-resolution viewing window, quick response, and good biocompatibility led to a satisfactory signal-to-noise ratio of MG-SLNP for real-time MGO bio-detection and imaging in vivo.

Rapid semi-quantitative analysis of hemolytic triterpenoid saponins in Lonicerae Flos crude drugs and preparations by paper spray mass spectrometry

Hemolytic triterpenoid saponins, as one of the index components of Lonicerae Flos (LF), are also the main components causing hemolytic risk of LF. In order to evaluate the quality and hemolytic risk of LF crude drugs and preparations, it was a key to establish a method for quantitative analysis of hemolytic triterpenoid saponins in LF. Here, a rapid method for quantitative determining hemolytic triterpenoid saponins had been developed via paper spray mass spectrometry (PS-MS), taking macranthoidin B (MaB), macranthoidin A (MaA) and dipsacoside B (DiB) as three target model compounds, and asperosaponin VI (ASA VI, a structural analogue) was used as internal standard. The sample solution was directly loaded and separated on chromatographic paper, sprayed and ionized by a high positive voltage, and ultimately analyzed by mass spectrometry. All analytes were detected with good linearity, precision, repeatability and accuracy. Compared with traditional high performance liquid chromatography with diode array detection (HPLC-DAD) method, PS-MS method had no significant difference in the semi-quantitative analysis of the actual samples, adding the advantages of shorter analysis time, lower reagent consumption and no-need chromatography separation process. This work provides a new strategy for fast determining hemolytic triterpenoid saponins in LF crude drugs and preparations.

Research Progress of NMR in Natural Product Quantification.

In the fields of medicine and health, traditional high-performance liquid chromatography or UV-visible spectrophotometry is generally used for substance quantification. However, over time, nuclear magnetic resonance spectroscopy (NMR) has gradually become more mature. Nuclear magnetic resonance spectroscopy has certain advantages in the quantitative analysis of substances, such as being nondestructive, having a high flux and short analysis time. Nuclear magnetic resonance spectroscopy has been included in the pharmacopoeiae of various countries. In this paper, the principle of nuclear magnetic resonance spectroscopy and the recent progress in the quantitative study of natural products by NMR are reviewed, and its application in the quantitative study of natural products is proposed. At the same time, the problems of using NMR alone to quantify natural products are summarized and corresponding suggestions are put forward.

A portable wireless intelligent electrochemical sensor based on layer-by-layer sandwiched nanohybrid for terbutaline in meat products

The aim of this study is to develop a portable wireless intelligent nanosensor (PWIN) for rapid cost-effective on-site determination of terbutaline (TRA) residue in meat products outdoors in comparison with traditional nanosensor and high-performance liquid chromatography (HPLC). The layer-by-layer sandwiched nanohybrid fabricated by platinum-palladium nanoparticles, carboxylated graphene and graphene-like molybdenum disulfide displayed a wide linear range of 0.55–14.9 μmol/L using the portable potentiostat with smartphone, and the result was almost close to the linear range (0.4–14 μmol/L) using the traditional potentiostat with desktop computer for TRA. The limit of detections were identified as 0.44 μmol/L and 0.18 μmol/L, respectively. PWIN displayed satisfactory recovery (91%−98.43%) of TRA in samples by the standard addition method and in comparison with both traditional sensor (93.79%−98%) and HPLC (93.4%–98.6%), revealing that PWIN for rapid cost-effective on-site analysis in the food safety field is feasible.

Simultaneous and Accurate Quantification of Multiple Antibiotics in Aquatic Samples by Surface-Enhanced Raman Scattering Using a Ti3C2Tx/DNA/Ag Membrane Substrate.

Rapid and accurate analysis of multiple targets in complex samples is still a big challenge in the fast detection field. Herein, we developed a rapid and accurate strategy for simultaneous quantification of trace multiple antibiotic residues in complex aquatic samples by surface-enhanced Raman scattering (SERS) using a Ti3C2Tx/DNA/Ag membrane substrate. This membrane substrate was proven to have good uniformity, reproducibility, stability, and SERS activity by a series of characterizations. Also, this substrate combined excellent electromagnetic enhancement and chemical enhancement effects, which endowed it with good sensitivity and selectivity during SERS analysis. It achieved the integration of multitarget separation, enrichment, and in situ detection, which significantly improved the selectivity, sensitivity, accuracy, and detection throughput by membrane substrate coupling with SERS for real-sample analysis. Finally, this rapid SERS analysis strategy was successfully applied to the simultaneous quantification of trace nitrofurantoin (NFT) and ofloxacin (OFX) in aquatic samples. It was observed that trace NFT and OFX were actually detected and simultaneously quantified to be 8.0-13.7 and 42.6-49.1 μg/kg in aquatic samples, respectively, with good recoveries of 88.0-107% and relative standard deviations of 0.3-5.5%. The results were verified by a traditional high-performance liquid chromatography method with relative errors of -9.8 to 5.3%. This strategy provided a methodological reference for accurate SERS quantification of multiple targets in complex samples.

Development of a Near Infrared Spectroscopy method for the in-line quantitative bilastine drug determination during pharmaceutical powders blending

The Food and Drug Administration (FDA)’s guidelines and the Process Analytical Technology (PAT) approach conceptualize the idea of real time monitoring of a process, with the primary objective of improvement of quality and also of time and resources saving. New instruments are needed to perform an efficient PAT process control and Near Infrared Spectroscopy (NIRS), thanks to its rapid and drastic development of last years, could be a very good choice, in virtue of its high versatility, speed of analysis, non-destructiveness and absence of sample chemical treatment. This work was aimed to develop a NIR analytical method for bilastine assay in powder mixtures for direct compression. In particular, the use of NIR instrumentation should allow to control the bilastine concentration and the whole blending process, assuring the achievement of a homogeneous blend. The commercial tablet formulation of bilastine was particularly suitable for this purpose, due to its simple composition (four excipients) and direct compression manufacturing process. Calibration and validation set were prepared according to a Placket-Burman experimental design and acquired with a miniaturized NIR in-line instrument (MicroNIR by Viavi Solution Inc.). Chemometric was applied to optimize information extraction from spectra, by subjecting them to a Standard Normal Variate (SNV) and a Savitzky-Golay second derivative pre-treatment. This spectra pre-treatment, combined with the most suitable wavelength interval (resulted between 1087 and 1217 nm), enabled to obtain a Partial Least Square (PLS) model with a good predictive ability. The selected model, tried on laboratory and production batches, provided in both cases good assay predictions. Results were confirmed by traditional HPLC (High Performance Liquid Chromatography) API (Active Pharmaceutical Ingredient) content uniformity test on the final product.

A Review on High Performance Liquid Chromatographic Methods for the Determination of Metformin

Background: The presence of pharmaceuticals (PACs) drugs in the environment and their detection and quantification have emerged as one of the challenging issues for the scientific community. Introduction: The gold standard, an anti-diabetic drug, Metformin has a strong potential to contaminate the aquatic bodies, being a highly polar drug. Different analytical methods based on spectroscopic evaluation or chromatographic techniques have been developed to find out the concentration of drug/ their metabolites. Methods: This review article discussed the chromatographic techniques for analysis of Metformin (in ng/L to μg/L) in aqueous samples, pharmaceutical drugs and biological fluids such as urine and human plasma are High-Performance Liquid Chromatography (HPLC), Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC), High-Performance Thin-layer Chromatography (HPTLC), Hydrophilic Interaction Liquid Chromatography HILIC–MS/MS, Liquid Chromatographic–tandem mass spectrometric (LC-MS-MS), Ultra-High Performance Liquid Chromatography (UPLC). Result: The relevance modifications of traditional HPLC methods for separation of the mixture of drugs with a focus on the lesser time, better resolution, sensitivity, symmetry of peaks, the limit of detection and accuracy of the results has been envisaged through research findings. Hydrophilic interaction liquid chromatography (HILIC) – tandem mass spectrometry method offered the possible solution for highly polar drugs detection and quantification in effluent and surface water samples. Conclusion: HPLC based analytical techniques offer the advantages viz. less time requirement, minimum usage of organic solvents and better separation and quantification of Metformin. The futuristic research approach lies in the development of newer extraction strategies, mobile phases and adsorbent materials for the HPLC based separations.

Using continuous chromatography methodology to achieve high-productivity and high-purity enrichment of charge variants for analytical characterization

Charge variants of biological products, such as monoclonal antibodies (mAbs), often play an important role in stability and biological activity. Characterization of these charge variants is challenging, however, primarily due to the lack of both efficient and effective isolation methods. In this work, we present a novel use of an established, high productivity continuous chromatography method, known as multi-column counter-current solvent gradient purification (MCSGP), to create an enriched product that can be better utilized for analytical characterization. We demonstrate the principle of this separation method and compare it to traditional batch HPLC (high performance liquid chromatography) or FPLC (fast protein liquid chromatography) methods, using the isolation of charge variants of different mAbs as a case study. In a majority of cases, we are able to show that the MCSGP method is able to provide enhanced purity and quantity of samples when compared to traditional fractionation methods, using the same separation conditions. In one such case, a sample prepared by MCSGP methodology achieved 95% purity in 10 hours of processing time, while those prepared by FPLC and HPLC achieved purities of 78% and 87% in 48 and 300 hours of processing time, respectively. We further evaluate charge variant enrichment strategies using both salt and pH gradients on cation exchange chromatography (CEX) and anion exchange chromatography (AEX) resins, to provide more effective separation and less sample processing following enrichment. As a result, we find that we are able to utilize different gradients to change the enrichment capabilities of certain charged species. Lastly, we summarize the identified mAb charge variants used in this work, and highlight benefits to analytical characterization of charge variants enriched with the continuous chromatography method. The method adds a new option for charge variant enrichment and facilitates analytical characterization of charge variants.

Enhanced photothermal signal detection by graphene oxide integrated long period fiber grating for on-site quantification of sodium copper chlorophyllin.

An enhanced photothermal signal detection method based on graphene oxide (GO) integrated long period fiber grating (LPFG) for on-site sodium copper chlorophyllin (SCC) quantification is proposed. SCC, as a porphyrin compound, can be photonically excited to induce a stronger photothermal effect. GO offers superior molecular adsorption and thermal conductivity properties; depositing it on the LPFG surface significantly improves the sensitivity and detection efficiency of the SCC photothermal signal, when irradiated with a 405 nm laser. The experimental results showed improved performance compared with those from uncoated LPFG, with a sensitivity of 0.0587 dB (mg L-1)-1 and a limit of detection (LOD) of 0.17 mg kg-1, which is also an order of magnitude lower than that of traditional high-performance liquid chromatography. The proposed method has potential applications in the fields of real-time food safety monitoring, environmental pollutant detection, and disease diagnosis.

Method comparison of HPLC-ninhydrin-photometry and UHPLC-PITC-tandem mass spectrometry for serum amino acid analyses in patients with complex congenital heart disease and controls

IntroductionMetabolomics studies are not routine when quantifying amino acids (AA) in congenital heart disease (CHD).ObjectivesComparative analysis of 24 AA in serum by traditional high-performance liquid chromatography (HPLC) based on ion exchange and ninhydrin derivatisation followed by photometry (PM) with ultra-high-performance liquid chromatography and phenylisothiocyanate derivatisation followed by tandem mass spectrometry (TMS); interpretation of findings in CHD patients and controls.MethodsPM: Sample analysis as above (total run time, ~ 119 min). TMS: Sample analysis by AbsoluteIDQ® p180 kit assay (BIOCRATES Life Sciences AG, Innsbruck, Austria), which employs PITC derivatisation; separation of analytes on a Waters Acquity UHPLC BEH18 C18 reversed-phase column, using water and acetonitrile with 0.1% formic acid as the mobile phases; and quantification on a Triple-Stage Quadrupole tandem mass spectrometer (Thermo Fisher Scientific, Waltham, MA) with electrospray ionisation in the presence of internal standards (total run time, ~ 8 min). Calculation of coefficients of variation (CV) (for precision), intra- and interday accuracies, limits of detection (LOD), limits of quantification (LOQ), and mean concentrations.ResultsBoth methods yielded acceptable results with regard to precision (CV < 10% PM, < 20% TMS), accuracies (< 10% PM, < 34% TMS), LOD, and LOQ. For both Fontan patients and controls AA concentrations differed significantly between methods, but patterns yielded overall were parallel.ConclusionSerum AA concentrations differ with analytical methods but both methods are suitable for AA pattern recognition. TMS is a time-saving alternative to traditional PM under physiological conditions as well as in patients with CHD.Trial registration numberClinicalTrials.gov Identifier NCT03886935, date of registration March 27th, 2019 (retrospectively registered).

A new RP-HPLC method as an auxiliary tool for optimization of sample preparation procedures for tracing of PPCPs of different hydrophilicities.

Recently, pharmaceutical and personal care products (PPCPs) have received considerable attention because of their increasing use. Analysis of PPCPs presents a significant analytical challenge, with high-performance liquid chromatography (HPLC) in reversed-phase mode, as the most widely used analytical technique. To facilitate the optimization of the procedures that are applied in the early stages of sample preparation, a simple and fast HPLC method is proposed in this work for the separation of some PPCPs with a wide range of hydrophilicity. Two columns were evaluated (Atlantis dC18 and Discovery HS F5); as for mobile phases: a formate buffer (40 mmol L-1, pH 4) and methanol were tested in a gradient mode. The fluorinated column allowed better separation in a shorter time and better resolution for all analytes (Rs > 1). The proposed method delivered good performance for the tracing of PPCPs and is a suitable alternative to traditional C18-based HPLC methods.