Corona Charged Aerosol Detector Research Articles

Delayed self-fertilization and chemical analysis of floral nectar of a perennial relative of the tomato and potato from Mexico

We studied the floral reproductive biology and nectar chemistry of Jaltomata grandiflora (Solanaceae), an apparently rare perennial of Michoacán, Mexico. During day 1, flowers are pistillate (stigma receptive, anthers not yet presenting pollen); flowers close for the night. Early in the morning of day 2, the corolla re-opens, stamens elongate to five times their earlier length, and anthers dehisce; the dehisced anthers remain about 2 mm from the stigma for much of day 2. In the afternoon of day 2, the corolla again closes, the corolla–androecium abscises, and only then can pollen be seen on the stigma. Protogyny and herkogamy likely promote outcrossing during days 1 and 2, respectively. Autonomous self-pollination takes place at the end of the corolla's life and allows fruit and seed production in the absence of pollinators but results in fruits that are lighter and contain fewer seeds than fruits resulting from manual self-pollinations. Carbohydrates from floral nectar samples were separated and quantified using hydrophilic interaction liquid chromatography coupled with corona charged aerosol detection. In nectar, mean sucrose concentration (0.482 mg/mg nectar), is about 10 and five times higher than glucose (0.043 mg/mg nectar) and fructose (0.095 mg/mg nectar) concentrations.

Establishment of SI-traceable purity assessment of Fumonisin B1 using a combination of quantitative 1H NMR and mass balance

The accurate purity assessment of Fumonisin B1 (FB1) is of great challenge due to the lack of inherent chromophore, which is important for the development of FB1 certified reference material. In this study, differential scanning calorimetry (DSC), mass balance and quantitative 1H nuclear magnetic resonance (qH NMR) methods were developed and validated for international system of unit (SI) traceable purity assessment of in-house prepared FB1. The thermodynamic analysis showed no typical melting peak was observed for FB1, indicating DSC was not applicable for purity assessment of FB1. A high-performance liquid chromatography coupled with corona charged aerosol detector (HPLC-CAD) method was developed and an isocratic elution procedure was optimized for the chromatographic purity analysis of FB1. The linear range of optimized HPLC-CAD method could not cover the concentration range of FB1 and the structure-related impurity in the raw material, which was identified to be partial hydrolyzed FB1 (pHFB1). The correction factor used to correct the chromatographic purity obtained by area normalization method was approximately 0.2 %. Moisture (0.30 %) and pHFB1 (0.48 %) were the main impurities according to the mass balance analysis. A mixture of dimethyl sulfoxide-d6 and trifluoroacetic acid-d was confirmed to be a suitable deuterated solvent for accurate qH NMR analysis of FB1. The purity obtained by mass balance (99.13 % with uncertainty of 0.06 %) and qH NMR (99.12 % with uncertainty of 0.28 %) showed good consistency and equivalent precision. These methods are expected to be applicable to development of FB1 certified reference material with metrological traceability to the SI unit to ensure comparable and reliable detection results.

Front Cover: Determination of lipid content and stability in lipid nanoparticles using ultra high‐performance liquid chromatography in combination with a Corona Charged Aerosol Detector

DOI: 10.1002/elps.202100244 The cover picture shows a cartoon depiction of an mRNA loaded lipid nanoparticle being broken up into its individual lipid components. The intent of this cover picture is to correlate the breaking up of the lipid nanoparticle macro-structure in order to identify and quantitate its individual components. The individual lipid components include pegylated lipids, cholesterol, helper lipids such as DSPC, and cationic lipids. The lipids are color-coded to highlight the differences between each type of lipid used to formulate LNPs. Also shown is a chromatogram from the article.

Quantification and Validation of Mesylate Ion in Dabigatran Etexilate Mesylate and Simultaneous Separation of Some Pharmaceutical Counterions using HPLC-HILIC Coupled with Corona Charged Aerosol Detector

Several counterions are commonly observed to be associated with drugs to improve their physicochemical properties. Counterions belonging to both inorganic and organic nature, like, I−, NO −, Br−, Cl−, K+, Na+, Li+, PO3− 4, SO2− 4, Zn2+, Mg2+, Ca2+, glutarate, succinate, mesylate, fumarate, citrate, oxalate and tartrate were chosen for the study. HPLC equipped with ZIC®-HILIC column with gradient elution and Corona – CAD was used to separate and detect various counterions in APIs. We have also demonstrated the application of the developed method by separating the counterions in dabigatran etexilate mesylate and sodium potassium tartrate. Further, the method was also applied to quantify the mesylate in dabigatran etexilate mesylate by CAD. This has been validated by determining system suitability, specificity, linearity, and accuracy. The linearity (r2>0.99) of the method was observed over the range from LOQ to 200%. The concentrations were 100 µg mL−1 for LOQ and 33 µg mL−1 for LOD. RSD of LOQ was ≤ 0.20 for standard methane sulphonic acid. The results of quantification of counterion mesylate by CAD were comparable with that of potentiometric titration. The method, thus can be used for determination and identification of anions and cations with API, carbohydrates and peptides.

Determination of lipid content and stability in lipid nanoparticles using ultra high-performance liquid chromatography in combination with a Corona Charged Aerosol Detector.

For many years, lipid nanoparticles (LNPs) have been used as delivery vehicles for various payloads (especially various oligonucleotides and mRNA), finding numerous applications in drug and vaccine development. LNP stability and bilayer fluidity are determined by the identities and the amounts of the various lipids employed in the formulation and LNP efficacy is determined in large part by the lipid composition which usually contains a cationic lipid, a PEG‐lipid conjugate, cholesterol, and a zwitterionic helper phospholipid. Analytical methods developed for LNP characterization must be able to determine not only the identity and content of each individual lipid component (i.e., the parent lipids), but also the associated impurities and degradants. In this work, we describe an efficient and sensitive reversed‐phase chromatographic method with charged aerosol detection (CAD) suitable for this purpose. Sample preparation diluent and mobile phase pH conditions are critical and have been optimized for the lipids of interest. This method was validated for its linearity, accuracy, precision, and specificity for lipid analysis to support process and formulation development for new drugs and vaccines.

Three-dimensional liquid chromatography with parallel second dimensions and quadruple parallel mass spectrometry for adult/infant formula analysis

Three dimensions of chromatographic separation, using split-flow two-dimensional liquid chromatography (SF-2D-LC) with two parallel second dimensions, LC × 2LC, combined with quadruple parallel mass spectrometry (LC3MS4) is demonstrated for analysis of NIST SRM 1849a adult/infant formula. The first dimension, 1D, was a conventional non-aqueous reversed-phase (NARP) HPLC separation using two C18 columns in series, followed by detection using an ultraviolet (UV) detector, a fluorescence detector (FLD), with flow then split to a corona charged aerosol detector (CAD), and then dual parallel mass spectrometry (MS), conducted in atmospheric pressure photoionization (APPI) and electrospray ionization (ESI) modes. The first second dimension, 2D(1), UHPLC was conducted on a 50.0 mm C30 column using a NARP-UHPLC parallel gradient for separation of short-chain triacylglycerols (TAGs) from long-chain TAGs, with detection by UV and ESI-MS. The second dimension, 2D(2), UHPLC was conducted using a 100.0 mm C30 column with a NARP-UHPLC parallel gradient for improved separation of TAG isomers, with detection by UV, an evaporative light scattering detector, and high-resolution, accurate-mass (HRAM) ESI-MS. Transferred eluent dilution was used to refocus peaks and keep them sharp during elution in both 2Ds. The separation space in the 2D(2) was optimized using multi-cycle (aka, “constructive wraparound”) elution, which employed flow rate programming. In the 1D, calibration lines for quantification of fat-soluble vitamins were constructed. A lipidomics approach to TAG identification and quantification by HRAM-ESI-MS was applied to the 2D(2). These experiments can be represented: LC1MS2 × (LC1MS1 + LC1MS1) = LC3MS4, or three-dimensional liquid chromatography with quadruple parallel mass spectrometry.

Determination of Free Amino Acids in Banlangen Granule and its Fractions by Solid Phase Extraction Combined with Ion-pair Hig-h Perfor mance Liquid Chromatography using a Corona-charged Aerosol Detector (SPE-HPLC-CAD)

Background: Banlangen granules are broad-spectrum effective antiviral drugs, and have a large clinical demand in China. Free amino acid is one of the main antiviral active ingredients of Banlangen granules. The pre-processing of samples by the existing pre-column derivatization reversed- HPLC method is complicated. Therefore, the determination of free amino acids (AAs) by underivatized ion-pair HPLC-CAD is advantageous for simplifying the preparation process and improving sensitivity. Objective: To better optimize AAs analysis methods, here a sensitive SPE-HPLC-CAD method with a better resolution was established for the determination of underivatized AAs in Banlangen Granule for the first time. Method: The analytes were separated only by HPLC using a Hypercarb column with gradient elution of solvent A (20 mM nonafluorovaleric Acid in water) and solvent B (0.3% trifluoroacetic acid in acetonitrile-0.3% trifluoroacetic acid in water (1:9, v/v)) at a flow rate of 0.15 mL/min. N2 gas pressure and evaporation temperature of CAD were held at a constant 58.6 psi and 60 ℃, respectively. Results: This method was linear over the respective concentration range of six amino acids. The precision, accuracy, stability and recovery were satisfactory in all samples examined. And the method was successfully applied to determination of free amino acids in Banlangen granules and its fractions. The total contents of six amino acids in 28 batches of Banlangen Granule were between 1.36 mg/g-11.62 mg/g. Conclusion: The proposed method could be a simple, accurate and sensitive alternative approach for the determination of free AAs in Banlangen Granule.

HPLC-DAD-CAD-based approach for the simultaneous analysis of hydrophobic drugs and lipid compounds in liposomes and for cyclodextrin/drug inclusion complexes

In recent decades liposomes have become attractive carriers for hydrophobic drugs to enhance their solubility and improve their therapeutic application. For liposomal drug products, both drug and lipid quantification are required by regulatory authorities, making the implementation of precise quantification methods a step of crucial importance in formulation development and quality control. Therefore, the present study is focused on the development and validation of a simple and time-saving method for the simultaneous analysis of hydrophobic drugs and conventional liposomal components. The new HPLC method was established with a combined detection by a diode array detector (DAD) and a corona charged aerosol detector (CAD). As a wide calibration range of the liposomal components can be achieved (10−1000 μg/mL), the analysis of samples with different drug to lipid ratios is enabled. Moreover, an excellent precision including repeatability and low limits of detection (≤ 1.8 μg/mL) and limits of quantification (≤ 5.9 μg/mL) were accomplished for all analytes. The method was successfully applied to liposomes incorporating mitotane. Everolimus was additionally analyzed as hydrophobic model drug. Furthermore, cyclodextrin/mitotane inclusion complexes were investigated to proof a broad range of applications for the developed method.

Impurity profiling of Compound Amino Acid Injection (6AA) using ion-pair high performance liquid chromatography coupled with corona-charged aerosol detection and high resolution mass spectrometry

The complex industrial production process of amino acids (AAs) leads to the existence of a certain amount of impurities in Compound Amino Acid Injection (6AA). It is difficult to obtain its comprehensive and systematic impurity profile using conventional ultraviolet (UV) detectors due to lack of a suitable chromophore in the structures of AAs and their impurities. In our study, a universal ion-pair high performance liquid chromatography (HPLC) method combined with high resolution mass spectrometer (HRMS) and charged aerosol detection (CAD) was developed to identify and determine the content of impurities in Compound Amino Acid Injection (6AA), respectively. After optimizing the content of trifluoroacetic acid (TFA) and heptafluorobutyric acid (HFBA) in the mobile phase on a C18 AQ column, HPLC-CAD method was developed and nine unknown impurities were detected. These impurities were successfully identified using HPLC coupled with orbitrap mass spectrometry and confirmed with their reference substances. The CAD parameters setting was optimized to improve the sensitivity and linearity of the methods before the developed method was validated. The results of validation reflected that the limit of detection (LOD) was approximately 2 ng (corresponding to approximately 0.02 % of L-isoleucine in injection). Under the optimized power function value (PFV) of CAD, the linear range of each impurity was 1 ∼ 200 μg mL−1 (the linear range of one of the impurities with higher content was 2 ∼ 400 μg mL−1) with coefficients of determination (R2) greater than 0.998. The recovery rates for nine impurities were 93.37 % ∼ 110.23 %. This study made full use of the qualitative functions of HRMS and the versatility of CAD, revealing possible impurities in the 6AA injection, which could provide reference for the safety research of it.

Simultaneous determination of six main components in Bushen Huoxue prescription by HPLC-CAD

BackgroundThe Bushen Huoxue prescription is a traditional Chinese medicine formula treating diabetic retinopathy, which was developed by our research group. Catalpol, puerarin, salvianolic acid B, ginsenoside Rg1, ginsenoside Rb1 and ginsenoside Rd are six of main effective components, which could be partly representative of this prescription. The corona charged aerosol detector (corona CAD) is one kind of universal detectors equipped with the high performance liquid chromatography (HPLC). The CAD has many advantages for the analysis of complex mixtures, but too few applications in traditional Chinese medicine compounds. ObjectiveThe aims of this study are to establish a method for the determination of six components in Bushen Huoxue prescription, and to increase the use of the CAD in traditional Chinese medicine compounds. MethodsHPLC-CAD analysis was performed on an Inertsil ODS-SP (4.6 mm × 250 mm, 5 μm) with a mobile phase consisting of 0.5 % formic acid solution(A)-acetonitrile(B) at a flow rate of 1 mL/min (0−7 min, 1 % B; 7−12 min, 1 %–12 % B; 12−22 min, 12 %–19 % B; 22-40 min, 19 %–28 % B; 40−43 min, 28 %–33 % B; 43−50 min, 33 % B; 50−65 min, 33 %–42 % B). The column temperature maintained at 30 ℃, the injection volume was 20 μL, the atomization temperature mode was LOW, the filtration constant (filter) was 3.6 and data collection rate was 10 Hz. The methodology was examined and the linearity of regression of different functions was compared. Sixteen batches of samples were prepared and their contents were determined. ResultsThe six compounds showed a better linearity (R2 > 0.9990) in their concentration ranges when using the linear function. The average recoveries were 99.18 %–101.30 %. Although the RSD value of puerarin and ginsenoside Rg1 was slightly out of 3 % during the average recovery investigation, all the other methodological investigations of the six components were within 3 %. The precision, stability and repeatability of the method were good. In sixteen batches of Bushen Huoxue prescription samples, the contents of six components were 0.3138 %–0.6042 % for catalpol, 0.8095 %–1.2917 % for puerarin, 0.7416 %–1.1189 % for salvianolic acid B, 0.0231 %–0.0418 % for ginsenoside Rg1, 0.0702 %–0.1724 % for ginsenoside Rb1, 0.0384 %–0.1196 % for ginsenoside Rd. ConclusionIn this experiment, a method for the determination of six components in Bushen Huoxue prescription based on HPLC-CAD was established with high accuracy, good repeatability and simple operation, and it can provide references for the improvement of quality standard of the Bushen Huoxue prescription. It is reasonable and accessible for the CAD application in the determination of traditional Chinese medicine compound prescriptions.

Analytical development of seamless procedures on cation-exchange chromatography and ion-pair chromatography with high-precision mass spectrometry for short-chain peptides

We report comprehensive analytical procedures for characterization of underivatized short-chain peptides by wet chemical treatment and ion-pair liquid chromatography with electrospray ionization–mass spectrometry (LC/ESI–MS). The chromatographic separation via a porous graphitic carbon stationary column eluted using an acetonitrile solvent gradient revealed a positive correlation between the retention time and the degree of hydrophobicity reflected in a distinct relationship between methylene (–CH2–) elongation of amino acids. We also validated the chromatographic separation utilizing an InertSustain PFP column and high-resolution mass spectrometry of the Orbitrap system, which supports the analytical accuracy for identification of monoisotopic mass. Using the quantitative analysis on a Corona charged aerosol detector, the recovery of the underivatized short-chain peptide fraction was >94.0 ± 4.9% (n = 10) after purification via cation-exchange chromatography. By eliminating the inorganic and organic matrix effect, we can avoid ion suppression and enhancement to demonstrate accurate analytical evaluations with robust mass spectroscopic responses. The developed method provides new insight into short-chain peptide chemistry that can be utilized for numerous interdisciplinary research applications.

Corona Charged Aerosol Detector in studying retention and β-cyclodextrin complex stability using RP-HPLC

Binding between cyclodextrin (CD) cavity and guest molecule in Reversed Phase High-Performance Liquid Chromatography (RP-HPLC) is dynamic process. In general, increasing CD concentration is inducing inclusion complex formation, leading to reduction of analyte’s retention time. Consequently, the shortness in retention time is a measure of complex stability in HPLC. However, under certain experimental conditions, the retention of some analytes could be prolonged even when concentration of CD in the mobile phase is increased. In order to reveal the cause of this unexpected retention behavior, the present study was carried on. The model mixture consisted of risperidone, olanzapine and their related impurities, while β-CD was selected among CDs, as in the previous study. In order to achieve fast equilibrium between free analyte and β-CD-analyte complex, β-CD was not added to the mobile phase, but only to the sample. Detection was performed with Corona Charged Aerosol Detector (CAD), suitable for non-chromophoric β-CD. When analyzing olanzapine impurity B-β-CD sample, three peaks were detected, namely free β-CD, β-CD-analyte complex and free analyte. The complex stability constant was calculated employing a modification of the Benesi-Hildebrandt equation and CAD has proven to be useful in complex stability constants assessment if retention of free analyte and β-CD-analyte complex is distinguished. For all other analytes only two peaks could be detected, because free analyte and formed complex are eluting at the same retention time. Under such circumstances, the authors proposed the methodology for calculating stability constants and confirmed its applicability to studied model mixture.

Simultaneous measurements of the molar radioactivity, radiochemical purity and chemical impurity in the [11C]choline injection using radio-HPLC with a corona-charged aerosol detector

[11C]choline has a weak UV absorption chromophore, and it is challenging to detect less than 1 μg/mL choline using radio-HPLC-UV. In this study, we established an analytical procedure of [11C]choline using the radio-HPLC coupled with the corona-charged aerosol detector. As a result, we achieved more than 100 GBq/μmol (over 0.1 μg/mL of choline) of molar radioactivity at the end of synthesis, over 95% of radiochemical purity, and more than 0.1 μg/mL of 2-dimethyoaminoethanol as a chemical impurity.

ANALYTICAL METHODS FOR THE DETERMINATION OF AMINOGLYCOSIDES ANTIBIOTICS BY CHROMATROGRAPHIC TECHNIQUE

Aminoglycosides antibiotics are considered to be the antimicrobial agents used frequently in the treatment of human diseases caused by a bacterial infection. Most of the aminoglycosides antibiotics are highly polar in nature and they are lacking the UV absorbing chromophore in the molecules. The present articles accentuate the analytical method associated with the analysis of aminoglycosides molecules. Various chromatographic techniques like liquid chromatography, gas chromatography; mass spectrometry were used for the detection of aminoglycosides antibiotics. However, due to its limitation in the ultraviolet-visible spectrophotometry (UV/Vis) technique, different types of detection techniques like corona-charged aerosol detector (CAD), electrochemical detector (ECD) were used as a most powerful and versatile technique for the demonstration of these molecules in the analytical field. Analytical methods help to ensure the quality of the drug products. This review paper is devoted to providing an overview of the key performance technique used for the application and detection of these aminoglycosides molecules.

Hydrophilic Interaction Chromatography Coupled with Charged Aerosol Detection for Simultaneous Quantitation of Carbohydrates, Polyols and Ions in Food and Beverages.

Here, we report an accurate and versatile method for the simultaneous determination of 17 sugars (arabinose, erythrose, fructose, galactose, glucose, isomaltulose, lactose, lyxose, maltose, maltotriose, mannose, raffinose, rhamnose, ribose, sucrose, sorbose and xylose), seven polyols (erythritol, inositol, lactitol, maltitol, mannitol, sorbitol and xylitol), five ions (K+, Br−, Cl−, NO3− and SO42−) and the pseudosaccharide acarbose. For compound separation, hydrophilic interaction chromatography (HILIC) coupled to a corona charged aerosol detector (CAD) was used. The method was validated for linearity, precision, reproducibility, retention factor and optimal injection volume. Standards were measured in the range of 1–1000 mg L−1 and showed good intraday and interday repeatability, as well as precision (relative standard deviation (RSD) < 5%). The LODs and LOQs for the 30 analytes were in the range of 0.032–2.675 mg L−1 and 0.107–8.918 mg L−1, respectively. This method exhibited correlation coefficients of at least R2 > 0.97 for all analytes. The method was tested in 24 food and beverage samples to validate the separation efficiency and sensitivity in natural food matrices and to show the practicability of its use for routine food analysis.

A new strategy for development of eco-friendly RP-HPLC method using Corona Charged Aerosol Detector and its application for simultaneous analysis of risperidone and its related impurities

Green analytical chemistry is primarily directed towards minimization of the amount of waste associated with either the sample preparation or analysis. Among different chromatographic methods, liquid chromatography is considered the least green, allowing for various possibilities for greening. Using green solvents such as ethanol or acetone in RP-HPLC, as an alternative to acetonitrile, is recently attracting an attention. Both ethanol and acetone are characterized with low toxicity, with certain drawbacks limiting their regular use in RP-HPLC. Ethanol has low eluotropic strength and causes high backpressures, while acetone shows high UV cut-off, making it unsuitable for UV/Vis detection. To overcome the existing problems, Corona Charged Aerosol Detector was employed for development of RP-HPLC methods for separation of risperidone and its structurally related impurities with either ethanol or acetone as organic modifier. The methods were optimized by experimental design methodology, while optimal conditions for separation were determined using Derringer's desirability function. Detailed assessment of 3D surface plots of Derringer's desirability function enabled selection of 0.6 mL min−1 flow rate and 20% (v/v) organic modifier content as optimal when using ethanol, while in case of acetone mobile phase flow rate was 0.8 mL min−1 and organic modifier content 17% (v/v). Methods were validated and their eco-friendly character was confirmed through Green Analytical Procedure Index (GAPI). Although both methods are ecologically acceptable, the main drawback is reflected in the fact that no recycling or another waste treatment method exist. In the end, acetone was prioritized over ethanol, due to lower health hazard and decreased amount of generated waste.

Matrix effect on quantification of sugars and mannitol developed during the postharvest of cocoa: an alternative method for traceability of aroma precursors by liquid chromatography with an evaporative detector.

The profile of reducing sugars developed during each stage of the postharvest of cocoa beans is an important quality index; these sugars are found to be one of the main precursors of flavor and neoformed compounds. However, its quantification after extraction from different parts of the bean is a challenge due to the complexity of the matrix. The primary aim of this study was to track the formation of reducing sugars and mannitol in samples obtained from various steps of the fermentation and drying processes of cocoa beans by validating a rapid matrix-corrected chromatographic method utilizing a corona-charged aerosol detector for improved sensitivity. The analytes were extracted from ground cocoa beans by solid phase extraction without a defatting step (20mg raw fermented and 10mg dried). The experimental variables influencing the effective detection were evaluated at different temperatures and signal filtering levels. Method validation studies showed an average recovery between 77.8 and 120% for fermented cocoa and between 79.6 and 117.7% for dried cocoa. A linear response was achieved for fructose, glucose, sucrose, and mannitol for a concentration range of 0.1-40mg/L, and maltose showed linearity in the range of 0.1-70mg/L. Regression coefficients (R) were 0.9991, 0.9993, 0.9992, 0.9995 and 0.9994, respectively. This method was successfully applied to a clone mix of cocoa from Antioquia, Colombia, to confirm the hydrolysis reaction of sucrose into glucose and fructose during fermentation and drying. A quality indicator of an efficient postharvest process in this study was determined to be a glucose percentage of 0.66% w/w and a fructose percentage of 1.46% w/w, which were higher than the values reported by other studies.

Determination of color developers replacing bisphenol A in thermal paper receipts using diode array and Corona charged aerosol detection—A German market analysis 2018/2019

Thermal papers (e.g. point of sale receipts, adhesive labels, tickets) significantly contribute to contamination of paper material cycles and the environment with substances of (eco-) toxicological concern. In particular, they contain color developers like endocrine disrupting bisphenols in typical concentrations of about 1–2 percent per weight (wt%). Bisphenol A (BPA) was used as the common color developer over the last decades, but it will be restricted for thermal paper application in the European Union to a limit of 0.02 wt% from 2020 onwards. Consequently, a variety of BPA substituents such as bisphenol S (BPS) and its derivatives gain importance in thermal paper application. In this study, a rapid, reliable and cost-effective method for identification and quantification of BPA, alternative color developers and related substances like sensitizers is presented based on HPLC separation coupled with diode array detection (DAD) and Corona charged aerosol detection (CAD). Quantification was performed with regard to the intended use of the substances in thermal papers. Besides traditional UV external calibration using reference standards, alternative quantification approaches, in particular UV chromophore concentration for BPS derivatives and CAD universal response technique for low-volatile color developers, were applied and compared in order to allow quantification without reference substances. A market analysis for intended used color developers and sensitizers was performed on thermal paper samples (n = 211) collected in Germany during 2018 and 2019. Pergafast 201 (in 41.7% of the samples) was the most common color developer with concentrations above 0.02 wt%, followed by BPA (36.0%), BPS (13.3%) and other BPS derivatives known as D8, D-90, BPS-MAE and TGSA, that are mainly present in adhesive labels. Sensitizers were determined in over 90% of the samples.

Development and validation of a novel high performance liquid chromatography-coupled with Corona charged aerosol detector method for quantification of glucosamine in dietary supplements.

IntroductionGlucosamine dietary supplements are commonly used for the management of osteoarthritis (OA). However, clinical trials have reported varying outcomes with regard to joint function and disease progression. One of the possible reasons for variability in observed effects of glucosamine could be that, unlike prescription drugs, the quality of manufactured dietary supplements is not closely monitored in many countries. Therefore, there is the possibility that the actual amount of glucosamine present in a dietary supplement is different from that claimed on the label. The quality control of glucosamine supplements is further complicated by the unavailability of a simple and effective analytical method for the analysis of glucosamine. Therefore, the aim of this study was to develop a simple analytical method that could be easily adapted by the pharmaceutical industry for routine analysis of glucosamine.AimsTo develop a novel high-performance liquid chromatography (HPLC) method for the quantification of glucosamine, and determine the amount of glucosamine present in a sample of dietary supplements commercially available in Australia and India.MethodsChromatographic separation of glucosamine was achieved using a zwitter-ionic hydrophilic interaction liquid chromatography column with a mobile phase consisting of 60% acetonitrile and 40% of 85 mM ammonium acetate, at a flow rate of 0.3 mL/min and column temperature 40°C. The developed method was validated for intra- and inter-day linearity, accuracy, precision, and reproducibility. The newly-developed method was subsequently used to analyse 12 glucosamine supplements.ResultsThe developed method was selective for glucosamine, which had a retention time of 5.9 min. The standard curve was linear with a correlation coefficient (r2) exceeding 0.99, over the range of 10–200 μg/mL for glucosamine. The relative standard deviations for intra- and inter-day accuracy, precision and reproducibility were all less than 4%. The amount of glucosamine determined in six Australian and six Indian glucosamine supplements ranged between 98.7–101.7% and 85.9–101.8% of the labelled values, respectively.DiscussionUnlike previous HPLC methods, this newly-developed HPLC technique does not require pre-derivatisation and can separate glucosamine from both hydrochloride and sulphate salts, and from other amino sugars, such as chondroitin sulphate present in dietary supplements. This simple and effective technique can be employed by analytical laboratories for the quality control of glucosamine dietary supplements.ConclusionThe current study has developed a new analytical technique using HPLC-Corona CAD, which can analyse underivatised glucosamine hydrochloride and sulphate within 6 minutes. Using the novel assay, we confirmed that unlike the tested Australian dietary supplements, only half of the tested Indian products had a glucosamine content within ±10% of what was claimed on the label.

The potential of Corona Charged Aerosol Detector for investigation of telmisartan: B-cyclodextrin inclusion complexes

Cyclodextrins (CDs) are widely used in pharmaceutical analysis due to its biodegradability and eco-friendly character. The particular structure of CDs, characterized by hydrophobic cavity, enables the formation of inclusion complexes with variety of organic compounds. As structures lacking chromophores, CDs could not be detected by Photodiode Array (PDA) detector and Corona Charged Aerosol Detector (CAD) was introduced as the most appropriate detector for the formed complexes. The aim of the study was to investigate the degree of complexation between telmisartan, used as a model substance, and b-CD. Moreover, the effect of different b-CD concentrations (5-15 mM) and pH of the aqueous part of mobile phase (3-7) on the degree of complexation was also assessed. The intensity of the formed complex appeared to be the highest when 15 mM b-CD was used for the complexation. Also, it was noticed that the increase in peak areas with an increasing b-CD concentration was more evident at pH 7 in comparison with the same trend at lower pH values. The reproducibility of the measurement was confirmed by low relative standard deviation (RSD) of peak areas within five measurements. These findings support the use of HPLC-CAD methods for studying the process of inclusion complexes formation.