Ternary Mobile Phase Research Articles

Comparative Analysis of Anisotropic Lipophilicity of a Series of 6-Chloro-1,3,5-Triazines Determined in Reversed Phase Ultra High Performance Liquid Chromatography System

Triazine derivatives are well-known commercially available compounds used for selective weed control in different crops, such as corn and sugarcane. Some of them are considered persistent organic compounds in the environment and it is important to improve the features of herbicide formulae, to estimate their physicochemical properties and to determine their retention behavior in modern analytical techniques that can be used in the determination of pesticides in environmental samples. The present study deals with a comprehensive analysis of the chromatographic behavior of a series of 6-chloro-1,3,5-triazines with alkyl and cycloalkyl substituents, among which some compounds possess herbicidal and fungicidal activity. The anisotropic lipophilicity of triazine derivatives was determined using reversed-phase ultra high performance liquid chromatography with octadecyl and phenyl columns and applying binary (methanol/water and acetonitrile/water) and ternary (methanol/acetonitrile/water) mobile phases under isocratic conditions. The retention data were analyzed using chemometric pattern recognition methods (hierarchical cluster analysis and principal component analysis) and sum of ranking differences method. The obtained results are excellent indicators of the retention behavior and the lipophilicity of the analyzed series of triazines and can serve as an outstanding basis for the development of new chromatographic methods for the determination of triazines in environmental samples.

A new single-reference quantitative method using liquid chromatography with relative molar sensitivity based on 1H-qNMR for khellactone esters from Peucedanum japonicum root extract.

Khellactone ester (KLE) quantification using the absolute calibration method is difficult owing to the unavailability of standard reagents that can guarantee purity. Herein, a new method was developed to quantify KLEs from Peucedanum japonicum root extracts using liquid chromatography (LC) without utilizing standards. This method used relative molar sensitivity (RMS) and 7-ethoxy-4-methylcoumarin as a single-reference (SR) compound instead of KLE standards. RMS is the sensitivity ratio of SR to analytes, determined using an offline combination of quantitative NMR and LC. LC was performed using a triacontylsilyl silica gel column of superficially porous particles with a ternary mobile phase. The range of the method was 2.60-509 µmol/L. The accuracy and precision were reasonable. This is the first study to apply the RMS method to both conventional LC and ultra-high-performance liquid chromatography using the same mobile phase and column. This method may aid the quality assurance of foods containing KLEs.

Simultaneous separation and detection of nine kynurenine pathway metabolites by reversed-phase liquid chromatography-mass spectrometry: Quantitation of inflammation in human cerebrospinal fluid and plasma

BackgroundThe kynurenine pathway (KP) generates eight tryptophan (TRP) metabolites collectively called kynurenines, which have gained enormous interest in clinical research. The importance of KP for different disease states calls for developing a low-cost and high-throughput chromatography-mass spectrometry method to evaluate the potential of different kynurenines. Simultaneous separation of TRP and its eight metabolites is challenging because they have substantial polarity differences (log P = −2.5 to +1.3). ResultsA low-cost, reversed-phase LC-MS/MS method based on polarity partitioning was established to simultaneously separate and quantitate all nine kynurenine pathway metabolites (KPMs) in a single run for the first time in the open literature. Based on stationary phase screening and ternary mobile phase optimization strategy, high polarity KPMs were retained while medium and low polarity KPMs were eluted in a shorter time. After method validation, we demonstrated the applicability of this LC/MS/MS method by quantitative measurement of all nine KPM in cerebrospinal fluid (CSF) and plasma among two groups of human subjects diagnosed with depression. Furthermore, we measured the differential KPMs in these two groups of low and high inflammation and correlated the results with CRP or TNF-α markers for depression. SignificanceOur proposed LC-MS/MS provides a new metabolite assay that can be easily applied in various clinical applications to simultaneously quantify multiple biomarkers in KP dysfunction.

The inversion of multiresponse partial least squares models, a useful tool to improve analytical methods in the framework of analytical quality by design

Analytical Quality by Design (AQbD) is the adaptation of Quality by Design (QbD) when it is applied to the development of an analytical method. The main idea is to develop the analytical method in such a way that the desired quality of the Critical Quality Attributes (CQAs), stated via the analytical target profile (ATP), is maintained while allowing some variation in the Control Method Parameters (CMPs).The paper presents a general procedure for selecting factor levels in the CMPs to achieve the desired responses, characterized by the CQAs, when liquid chromatographic methods are to be used for the simultaneous determination of several analytes. In such a case, the CMPs are usually the composition of the ternary mobile phase, its flow rate, column temperature, etc., while typical CQAs refer to the quality of the chromatograms in terms of the resolution between each pair of consecutive peaks, initial and final chromatographic time, etc. The analytical target profile in turn defines the desired characteristics for the CQAs, the reason for the whole approach.The procedure consists of four steps. The first is to construct a D-optimal combined design (mixture-process design) to select the domain and levels of the CMPs. The second step is to fit a PLS2 model to predict the analytical responses expressed in the ATP (the good characteristics of the chromatogram) as a function of the CMPs. The third step is the inversion of the PLS2 model to obtain the conditions necessary to obtain the preset ATP in the corresponding CQAs. The inversion is performed computationally in order to estimate the Pareto front of these responses, namely, a set of experimental conditions to perform the chromatographic determination for which the desired critical quality attributes are met. The fourth final step is to obtain the Method Operable Design Region (MODR), that is, the region where the CMPs can vary while maintaining the quality of the CQAs.The procedure has been applied to some cases involving different analytes, all of which are regulated by the European Union due to their toxicity to human health, namely five bisphenols and ten polycyclic aromatic hydrocarbons.

A New UHPLC Analytical Method for St. John’s Wort (Hypericum perforatum) Extracts

Commonly used to treat mood disorders, St. John’s Wort (Hypericum perforatum) is a popular herb in the natural health products industry. The potency of its active ingredients can be determined using a number of different analytical methods, but it is more widely determined using high performance liquid chromatography (HPLC). While monographs in the United States Pharmacopeia (USP) can often be relied upon for suitable analytical methods, the method proposed for determining hypericin content in St. John’s Wort products is inefficient in carrying out this purpose. This paper presents a modified new HPLC method for determining the hypericin content that can also be used for St. John’s Worts capsules and tablets by making use of purified hypericin as a chemical standard instead of oxybenzone, applying a wavelength of 588 nm during analysis and utilizing a binary instead of ternary mobile phase gradient. The resulting method and sample chromatograms provide better resolved, more easily identifiable peaks, shorter run time, and increased sustainability compared to the original USP method. This proposed method was developed using the more refined ultra-high performance liquid chromatography (UHPLC) and serves as a more accurate and reliable method for determining hypericin content in St. John’s Wort.

Unique selectivity of tetrahydrofuran-2-propanol-water ternary mobile phases on a superficially porous particle column in reversed-phase liquid chromatography

Three mixed mobile phase organic modifiers, tetrahydrofuran: 2-propanol 1:1 (v/v), tetrahydrofuran: 2-propanol: 1:3 (v/v), and tetrahydrofuran: 2-propanol: 3:1 (v/v) were studied at 20–70% (v/v) total organic solvent compositions. The solvent strength parameters for the three mixed organic modifiers and system properties were compared to those of more established binary solvent systems, acetonitrile-water and methanol-water. To interpret intermolecular interactions responsible for retention for the three mixed mobile phase organic modifiers, system maps were constructed and compared with acetonitrile and methanol. Three mixed organic mobile phase modifiers on one stationary phase chemistry (Kinetex C18) provide different selectivity than the more established acetonitrile and methanol mobile phase modifiers on the same stationary phase (Kinetex C18) as well as different stationary phase chemistries (Kinetex Biphenyl, Kinetex Phenyl-Hexyl, Kinetex F5, Kinetex XB-C18, and Kinetex EVO C18). The solvation parameter models for all three mixed mobile phase systems the coefficient of determination ranged from 0.991 to 0.999, the Fisher statistic from 338 to 1850, and the standard error of the estimate ranged from 0.024 to 0.097.

Chemometrics of anisotropic lipophilicity of anticancer androstane derivatives determined by reversed-phase ultra high performance liquid chromatography with polar aprotic and protic modifiers

The research of the use of steroid compounds in the treatment of various types of cancer has a history of more than 50 years. Numerous steroid derivatives have expressed significant anticancer activity, however the thorough analysis of their physicochemical and toxicological properties is required prior to their clinical application. The present study is focused on the characterization of physicochemical properties of a series of previously synthesized new androstane derivatives (16E-hydroxyimino derivatives, D-homo lactones and D-seco dinitriles) with anticancer activity applying reversed-phase ultra high performance liquid chromatography (RP-UHPLC) system under isocratic conditions and chemometric tools, including in silico determination of their absorption, distribution, metabolism, excretion and toxicity (ADMET) properties. The chromatographic analysis was carried out applying two two-component and one ternary mobile phases with aprotic (acetonitrile) and protic (water and methanol) solvents. The conducted quantitative structure-retention relationship modeling resulted in two univariate and nine multivariate linear mathematical models that successfully correlate the retention parameters (logk) with descriptors of molecular polarity/lipophilicity (tPSA, REF, Average LogP, ClogP, ALOGP, LogS-SILICOS-IT, AClogS), descriptors that mainly depend on intermolecular interactions (BP, CP, CT, DE, HL) and ADMET descriptors (SWISSLogKpSP, GPCR, HIA, EI). The quality of the models was proved by the internal and external validation, while the robustness of the models was confirmed by Y-randomization test. Considering the established meaningful relationships between physicochemical/ADMET properties and retention parameters, the determined logk parameters of the analyzed series of steroid derivatives can be considered to be a biopharmaceutical property from the perspective of lipophilicity.

Dual Organic Modifier, Solid Core Technology and Quality by Design Based Tripartite Synergistic Model for Development and Validation of Stability Indicating Method by Reverse Phase-High Performance Liquid Chromatography for Assay and Impurities of Etoricoxib Tablets

Tripartite synergistic model of solid core technology, dual organic modifiers and combined mixture design was implemented to achieve combined assay and related substances method by reverse phasehigh performance liquid chromatography with short run time, enhanced sensitivity and improved resolution between multiple impurity peaks. pH of mobile phase, ternary mobile phase composition and high performance liquid chromatography column temperature are experimented as variable parameters. Acetonitrile and isopropyl alcohol mixture was experimented as dual organic modifier. Special focus was given to detailed methodology of dealing with elution order changes by assigning negative sign for resolution. Separation of etoricoxib and related impurities was evaluated as a case study to prove this concept. The method was developed with Ascentis® Express C18, 150×4.6 mm, 2.7 μ column. Mobile phase comprised of buffer (0.1 % v/v ortho phosphoric acid, pH 3.6), acetonitrile and isopropyl alcohol (65.3:29:5.7 v/v) with a flow rate of 1.0 ml/min and ultraviolet detection at 285 nm. Forced degradation studies revealed that the method was stability indicating, suitable for both assay and impurities of drug product. The recoveries for impurities and assay were found to be in the range of 94.0 %-111.0 % and 97.9 %-101.8 %, respectively. Linearity was established for impurities and assay in the range of 0.25-2.0 μg/ml and 125-750 μg/ml, respectively. The method was validated as per international conference on harmonisation guidelines. The method can be successfully employed for determination of assay and impurities of etoricoxib in bulk drugs and formulations.

Efficient separation and quantification of methyl palmitate and methyl oleate in biodiesel mixture using reverse-phase high performance liquid chromatography

ABSTRACT The excessive utilization of petroleum resources leads to global warming, crude oil price fluctuations, and fast depletion of petroleum reserves. Biodiesel (Fatty Acid Methyl Ester, FAME) has gained importance as a clean and renewable energy source over the last few years. It is produced by reacting vegetable oils and short-chain alcohols via transesterification/esterification reaction. The properties of biodiesel depend on the vegetable oils’ fatty acid composition due to the saturated and unsaturated fatty acid content variation. During the FAME quantification analysis, separation of methyl palmitate (MeP) and methyl oleate (MeO) are major challenges in the C18 column in High Performance Liquid Chromatography (HPLC). These components are difficult to quantify as they elute simultaneously by forming an overlapping peak. A new reverse-phase HPLC separation method with C18 column has been developed to efficiently separate and quantify FAMEs derived from palm oil. UV-VIS detector was used at 205 nm. The FAMEs separation was achieved using ternary mobile phase solvents acetonitrile, water, and acetone with the composition of 62%, 33%, and 5% in an isocratic flow with 2.20 mL/min flowrate and 45 °C column temperature. Methyl esters were analyzed with satisfactory linearity (r 2 >0.99), repeatability (relative standard deviation <2%), and sensitivity (limit of quantification).

The critical role of mobile phase pH in the performance of oligonucleotide ion-pair liquid chromatography-mass spectrometry methods.

The critical role of mobile phase pH in the performance of oligonucleotide ion-pair liquid chromatography-mass spectrometry methods.

Preparation of Chlorophyll Nanoemulsion from Pomelo Leaves and Its Inhibition Effect on Melanoma Cells A375.

Pomelo (Citrus grandis), an important fruit crop grown in tropical and subtropical areas, is cultivated mainly in Asian countries. The dominant pigment in pomelo leaves, chlorophyll, has been reported to possess many biological activities such as antioxidant, anti-inflammation and anticancer. The objectives of this study were to determine chlorophylls in Pomelo leaves by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and to encapsulate the isolated chlorophylls from preparative column chromatography into a nanoemulsion system for elucidating the inhibition mechanism on the growth of melanoma cells A375. The results showed that chlorophyll a and chlorophyll b could be separated within 25 min by using a C18 column and a gradient ternary mobile phase of acetone, acetonitrile and methanol. Pomelo leaves mainly contained chlorophyll a (2278.3 μg/g) and chlorophyll b (785.8 μg/g). A highly stable chlorophyll nanoemulsion was prepared with the mean particle size being 13.2 nm as determined by a dynamic light scattering (DLS) method. The encapsulation efficiency of chlorophyll nanoemulsion was 99%, while the zeta potential was −64.4 mV. In addition, the chlorophyll nanoemulsion possessed high thermal stability up to 100 °C and remained stable over a 90-day storage period at 4 °C. Western blot analysis revealed that chlorophyll nanoemulsion and extract could upregulate p53, p21, cyclin B and cyclin A as well as downregulate CDK1 and CDK2 in a concentration-dependent manner for inhibition of melanoma cells A375. Furthermore, chlorophyll nanoemulsion and extract could upregulate Bax and cytochrome C and downregulate Bcl-2, leading to activation of caspase-9, caspase-8 and caspase-3 for the induction of cell apoptosis. Compared to chlorophyll extract, chlorophyll nanoemulsion was more effective in inhibiting the growth of melanoma cells A375.

Dual-Mode Gradient HPLC and TLC Densitometry Methods for the Simultaneous Determination of Paracetamol and Methionine in the Presence of Paracetamol Impurities.

BackgroundParacetamol is one of the most widely analgesic and antipyretic drugs recently integrated into the supportive therapy of COVID-19. The pharmaceuticals containing methionine with paracetamol may contribute to avoid hepatotoxicity and eventual paracetamol overdose-dependent death.ObjectiveThe current work purposes to develop and validate two chromatographic methods for the simultaneous determination of methionine and paracetamol in presence of two paracetamol impurities (4-nitrophenol and 4-aminophenol).MethodsTwo chromatographic methods were established and validated according to the International Conference on Harmonization guidelines. The first one was a RP-HPLC/UV method based on applying a “dual-mode” gradient elution. The separation was realized via varying both the composition of the ternary mobile phase (acetonitrile–methanol–water) and its flow rate. This strategy enabled a relatively rapid analysis with a satisfactory resolution, although the investigated compounds exhibit a significant difference in lipophilicity. The second one relied on TLC- densitometry, where the optimum separation was realized using a quaternary mobile phase system composed of butanol–dioxane–toluene–methanol (8: 2.5: 3.5: 0.3, by volume). Both methods were monitored at 220 nm.ResultsThe developed methods were proven to be robust, accurate, specific, and appropriate for the routine analysis of paracetamol in its pure form or in pharmaceutical formulations with methionine in quality control laboratories.ConclusionsThe corresponding methods are suitable to determine methionine and paracetamol in the presence of paracetamol impurities.HighlightsThe study achieves the analysis of methionine and paracetamol in the presence of paracetamol impurities via the application of HPLC and TLC- densitometry methods.

A new approach based on inversion of a partial least squares model searching for a preset analytical target profile. Application to the determination of five bisphenols by liquid chromatography with diode array detector

The paper shows a procedure for selecting the control method parameters (factors) to obtain a preset ‘analytical target profile’ when a liquid chromatographic technique is going to be carried out for the simultaneous determination of five bisphenols (bisphenol-A, bisphenol-S, bisphenol-F, bisphenol-Z and bisphenol-AF), some of them regulated by the European Union.The procedure has three steps. The first consists of building a D-optimal combined design (mixture-process design) for the control method parameters, which are the composition of the ternary mobile phase and its flow rate. The second step is to fit a PLS2 model to predict six analytical responses (namely, the resolution between each pair of consecutive peaks, and the initial and final chromatographic time) as a function of the control method parameters. The third final step is the inversion of the PLS2 model to obtain the conditions needed for attaining a preset analytical target profile.The computational inversion of the PLS2 prediction model looking for the Pareto front of these six responses provides a set of experimental conditions to conduct the chromatographic determination, specifically 22% of water, mixed with 58% methanol and 20% of acetonitrile, keeping the flow rate at 0.66 mL min−1. These conditions give a chromatogram with retention times of 2.180, 2.452, 2.764, 3.249 and 3.775 min for BPS, BPF, BPA, BPAF and BPZ, respectively, and excellent resolution among all the chromatographic peaks.Finally, the analytical method is validated under the selected experimental conditions, in terms of trueness and precision. In addition, the detection capability for the five bisphenols were: 596, 334, 424, 458 and 1156 μg L−1, with probabilities of false positive and of false negative equal to 0.05.

Charge variant analysis of protein-based biopharmaceuticals using two-dimensional liquid chromatography hyphenated to mass spectrometry

The profile of charge variants represents an important critical quality attribute of protein-based biopharmaceuticals, in particular of monoclonal antibodies, and must therefore becontrolled. In this work, 2D-LC methods for charge variant analysis were developed using a strong cation-exchange chromatography (SCX) as first dimension (1D) separation. Non-porous SCX (3 µm) particle columns and different mobile phases were evaluated using a test mixture of some standard proteins of different size and pI (comprising myoglobin, bovine serum albumin, cytochrome c, lysozyme and β-lactoglobulin) and two monoclonal IgG1 antibodies (NIST mAb and Secukinumab). The most promising 1D eluent for SCX was a salt-mediated pH-gradient system using a ternary mobile phase system with 2-(N-morpholino)ethanesulfonic acid, 1,3-diamino-2-propanol and sodium chloride. For the second dimension (2D), a desalting reversed-phase liquid chromatography (RP-LC) was chosen to enable the hyphenation of the charge variant separation with mass spectrometric (MS) detection. While for intact mAbs the 2D just served for desalting without additional selectivity, the 2D contributed some orthogonal selectivity for the mAb fragment separation. Various core-shell and monolithic columns were tested and variables such as gradient time and flow rate systematically optimized. Unexpectedly, a C4 400 Å column (3.4 µm diameter with 0.2 µm porous shell) provided higher peak capacities compared to the same 1000 Å column (2.7 µm diameter with 0.5 µm porous shell). A thinner shell appeared to be more advantageous than wider pores under high flow regime. An ultra-fast RP-LC method with a run time of one minute was developed using trifluoroacetic acid which was later replaced by formic acid as additive for better MS compatibility. The successful hyphenation of the two orthogonal separation modes, SCX and RP-LC, could be demonstrated in the multiple heart-cutting and the full comprehensive mode. MS analysis using a high-resolution quadrupole time-of-flight instrument enabled to identify different glycoforms and some major charge variants of the antibody at the intact protein level as well as on the subunit level (Fc/2, Lc, Fd’) in a middle-up approach by 2D-LC-ESI-MS analysis.

Simultaneous Determination of Paracetamol, Propyphenazone and Caffeine in Presence of Paracetamol Impurities Using Dual-Mode Gradient HPLC and TLC Densitometry Methods.

Two chromatographic methods were validated for the determination of the widely prescribed analgesic and antipyretic drug combination of paracetamol (PC) (recently integrated into the supportive treatment of COVID-19), propyphenazone (PZ) and caffeine (CF) in the presence of two PC impurities, namely 4-aminophenol and 4-nitrophenol. A “dual-mode” gradient high-performance liquid chromatography method was developed, where the separation was achieved via “dual-mode” gradient by changing both the ternary mobile phase composition (acetonitrile: methanol: water) and the flow rate. This enables a good resolution within a relatively shorter analysis time. The analysis was realized using Zorbax Eclipse XDB column C18, 5 μm (250 × 4.6 mm) and the UV detector was set at 220 nm. The other method is a thin-layer chromatography densitometry method, where the separation was achieved using a mobile phase composed of chloroform: toluene: ethyl acetate: methanol: acetic acid (6: 6: 1: 2: 0.1, by volume). Densitometric detection was performed at 220 nm on silica gel 60 F254 plates. The developed methods were fully validated as per the ICH guidelines and proved to be accurate, robust, specific and suitable for application as purity indicating methods for routine analysis of PC in pure form or in pharmaceuticals with PZ and CF in quality control laboratories.

Characterization of Tween® Surfactants by MALDI TOF-MS and High Performance Liquid Chromatography in a Ternary Mobile Phase

AbstractDifferent hydrophobic and hydrophilic functionalities are produced in the reaction mixture of Tween® surfactants which affect the physiochemical properties of the final product. Only hydrophilic fractions and monoesters were separated in the binary mobile phase. MALDI TOF-MS of Tween® 40 revealed the identification of peaks separated in binary mobile phase (methanol-water). Liquid adsorption chromatography was performed on a gradient system on a SynergiTM fusion reverse phase column. Mobile phase composition used for this separation was a ternary phase gradient starting from 41 % methanol, 47 % acetone and going to 96 % acetone for the analysis time of 60 minutes. In the ternary mobile phase, gradient all the species such as polyethylene glycol, sorbitan and isosorbide ethoxylates, mono-, di- and triesters of sorbitan and isosorbide ethoxylates were well resolved in an of 60 minutes analysis time. The above separation mechanism can be employed for the analysis of polymeric multifunctional surfactant compositions.

Detection and quantification of vitamins in microliter volumes of biological samples by LC‐MS for clinical screening

A method for simultaneous determination of water‐soluble vitamins B1, B2, B3 (nicotinamide), B5, B6 (pyridoxamine), B9 and fat‐soluble vitamins E (α‐tocopherol) and K1 in tears, and B1, B2, B3, B5, B6, B9, A (retinol), and E in blood serum is described. Liquid chromatography‐mass spectrometry (LC‐MS) was used with a ternary mobile phase of water and acetonitrile containing 0.1% formic acid and methanol containing 5 mM ammonium formate. Vitamins were quantified using an internal standard method. Using 25 μL injection volumes, the limits of detection were in the range of 0.066‐5.3 ng in tear, and 0.087‐1.1 ng in serum with linear responses for all vitamins. Intra‐ and inter‐day precision and recoveries were satisfactory. This is the first study to demonstrate simultaneous vitamin detections in microliters of biological samples which has distinct advantages in many diagnostic applications with limited available fluids (e.g., tears; elderly anemic blood) or sampling small subjects (e.g., rodents). © 2018 American Institute of Chemical Engineers AIChE J, 64: 3709–3718, 2018

HPLC – Quality by Design Approach for Simultaneous Detection of Torsemide, Spironolactone and Their Degradant Impurities

Abstract A simple, highly robust (quality by design (QbD) approach), precise and accurate method using high performance liquid chromatography coupled to mass spectrometry has been established for the simultaneous separation, identification and quantitation of a Torsemide (TOR), spironolactone (SPI) and their degradant impurities. The chromatographic separations of drugs and impurities were achieved on a inertsil ODS-3 µm C18, 150 mm × 4.6 mm, while the isocratic elution using a ternary mobile phase mixture of methanol, acetonitrile and water (5:3:2 v/v/v) at a flow rate of 0.2 mL/min was adopted for achieving optimum separations. The quantitation of torsemide and spironolactone was accomplished by UV detection at 254 nm and identification of the degradants were done by comparing identical mass in mass spectrometer. The recoveries of the torsemide and spironolactone were obtained higher than 98 % with good validation parameters; linearity (r2&gt;0.994), LOD and LOQ was 10 and 33 ng for TOR and 75 and 248 ng for SPI respectively. The quality by design (QbD) approach has been successfully utilized to prove the method is robust even deliberate changes in critical parameters.

A Simple, Sensitive, and Label-Free Platform for the Quantification of Lactoferrin in Camel and Goat Milk Based on Thin-Layer Chromatography

Lactoferrin is a multifunctional glycoprotein secreted in most body fluids, especially in milk. It has been identified in many mammalian species, such as human, goat, cow, and camel. Lactoferrin exerts a significant protective biological role by acting as an antimicrobial, antiviral, immunomodulatory, and anti-inflammatory agent. This work describes a simple, sensitive, direct, inexpensive, and label-free method for quantifying lactoferrin in camel and goat milk based on thin-layer chromatography (TLC). Analysis and quantification of lactoferrin were done through simple protein extraction procedure followed by subjecting the obtained extract to TLC using RP-18 TLC silica gel plates and a ternary mobile phase composed of 2-propanol: TFA: water (40:5:55, v:v:v). Densitometric detection was carried out at 250 nm. The proposed method showed linear calibration curves over the range of 10.0–205.0 µg/mL. The limit of detection and limit of quantitation were found to be 3.50 and 10.0 µg/mL, respectively. The method was fully validated according to the ICH guidelines. The average lactoferrin concentrations in camel and goat milk were determined as 29.70 ± 0.69 and 38.12 ± 0.53 μg/mL, respectively. The reliability of the assay was demonstrated through direct comparison with a previously reported high-performance liquid chromatography (HPLC) method for lactoferrin analysis. The presented study represents the first report for the application of TLC in quantifying lactoferrin in natural extracts.

Enantioseparation of isoxazolines with functionalized perphenylcarbamate cyclodextrin clicked chiral stationary phases in HPLC.

The enantioseparations of 12 isoxazoline racemates were explored with four perphenylcarbamate cyclodextrin (CD) clicked chiral stationary phases (CSPs) in high performance liquid chromatography (HPLC). The results demonstrated that the functionalities on phenylcarbamate moiety greatly determined the chiral separation ability of CD clicked CSPs. Among of them, per(3-chloro-4-methylphenylcarbamate) CD clicked CSP (CCC3M4-CSP) exhibited the best enantioseparation ability, affording 4ClPh-OPr with a chiral resolution over 20 in ternary eluent mobile phases. The optimization of CSPs structures provided wide platform for their chiral separations towards multi-mode HPLC.