Thin-layer Chromatography Plates Research Articles

The Identification of Six Estrogen Preparations by Combining Thin-Layer Chromatography with Micro-Raman Imaging Spectroscopy

A method for identifying six estrogen preparations by thin-layer chromatography combined with Raman imaging microscopy (TLC-RIM) was established. An appropriate pretreatment method was adopted to extract and purify the six estrogen preparations. After that, each estrogen extraction solution was spotted on a thin-layer chromatography plate. Estriol (E3), estradiol (E2), estradiol valerate (EV), estradiol benzoate (EB), nilestriol (CEE), and ethinylestradiol (EE2) were separated by TLC, and their Rf value and localization were determined under a UV lamp at 254 nm, followed by the in situ enrichment of the drug component. Using a 532 nm laser as the light source, the Raman scattering spectrum of the component was directly collected by micro-Raman imaging. The Rf values after TLC separation of the six estrogens and their Raman spectra can, respectively, reflect differences in polarity and structure, and they are not affected by the excipients of preparation. The detection limits of the six estrogens are 0.636, 1.00, 0.687, 0.497, 0.649, and 0.626 mg/mL. Based on the intensity of the minimum characteristic peak, the stability results within 40 min showed that the RSD of each substance is 1.34, 2.06, 1.65, 3.99, 1.16, and 2.71%, respectively. This method has strong specificity, good stability, and high sensitivity, and it can provide a new reference for improving the identification standards of estrogen preparations.

Phytochemistry of Petroselinum crispum (Mill.) Fuss, Murraya koenigii (L.) Spreng. and Cinnamomum tamala (Buch.-Ham.) T. Nees & C. H. Eberm. and in silico studies of the role of their bioactive components against cancer

Phytochemical profiling using reliable equipment and validated methods helps us know the medicinal value of the plants. Since natural compounds have fewer side effects, they can serve as replacements for synthetic drugs that are being used in the treatment of challenging chronic diseases like cancer. The present study focuses on the bioactive phytochemical profiling of Petroselinum crispum (Mill.) Fuss, Murraya koenigii (L.) Spreng., and Cinnamomum tamala (Buch.-Ham.) T. Nees & C. H. Eberm. and in silico studies to check the anticancer potential of their bioactive components. In thin-layer chromatography (TLC) plate analysis, it was found that the methanolic extracts of plants contained the maximum number of components. Gas chromatography–mass spectrometry (GC-MS) analysis of the methanolic extracts of plants showed the presence of 22 bioactive components. High-performance thin-layer chromatography (HPTLC) analysis of the extracts of these plants showed the important chromatographic peak, apigenin. In silico studies showed the binding efficacy of selected bioactive components observed in the analysis of plant extracts. Amongst them, apigenin was found to be most effective at binding to the receptors of targeted cancer cells, viz., hepatocellular carcinoma, lung, and breast cancer. After the analysis of the study, it was arrived at the conclusion that the plants, viz., P. crispum, M. koenigii, and C. tamala, possess various bioactive components, and some of these components have anticancer potential. Therefore, in vivo and in vitro studies should be essentially conducted for the development of cancer-preventive drugs.

Simultaneous Estimation of Monoterpenes (Eugenol, Eucalyptol and R-Limonene) by HPTLC Densitometric Method and Its Validation.

Plant-derived monoterpenes have various pharmacological applications, but the problem lies with their detection and estimation. Hence, it is crucial to develop a robust technique to overcome this problem. This work was aimed at developing a swift, accurate and reproducible technique for the simultaneous detection of three monoterpenes, namely, eugenol, eucalyptol (1,8- cineole), and R-limonene, using the high-performance thin-layer chromatography technique, as per International Council of Harmonization (ICH) guidelines. The best results were obtained in the eluent mixture prepared by using hexane: toluene: ethyl acetate (6:3:1, v/v/v), and silica gel-coated aluminum thin layer chromatography (TLC) plates 60F254 as a stationary phase that produced very sharp and well-resolved symmetrical peaks for eugenol, eucalyptol, and R-limonene at Rf values of 0.47 ± 0.03, 0.56 ± 0.03, and 0.71 ± 0.03, respectively. The linear range for eugenol, eucalyptol, and R-limonene was 1 to 15 ng/ spot (r2 = 0.9906), 100 to 600 ng/spot (r2 = 0.99625), 50 to 300 ng/spot (r2 = 0.9873), respectively. Furthermore, the limit of detection (LoD) and limit of quantitation (LoQ) values for eugenol were obtained at 0.0129 and 0.0391 ng/spot, followed by eucalyptol (0.82 and 2.48 ng/spot) and R-limonene (0.594 and 1.8 ng/spot), respectively. To our knowledge, we are the first to report a quick and reproducible high-performance thin-layer chromatography (HPTLC) technique for the simultaneous determination of eugenol, eucalyptol (1,8-cineole), and R-limonene. This method can further be used for the quantification of these secondary metabolites in plant extracts, enriched fractions, and pharmaceutical formulations.

A Comparative Analysis of Traditional Latent Fingerprint Visualization Methods and Innovative Silica Gel G Powder Approach

Latent fingerprints are a common source of information for forensic experts and law enforcement agencies. The thin layer chromatography (TLC) plates that are prepared in this work are made with silica gel G powder. Latent fingerprint remnants are made up of secretions from the nose, palm, and sebaceous, apocrine, and eccrine glands (sweat). However, the quest for more versatile and effective techniques persisted, leading to the emergence of innovative approaches like Silica Gel G powder. The silicon atoms are linked to –OH groups at the silica gel’s surface. A latent fingerprint is an imprint left by direct contact with a surface or object that is not apparent to the unaided eye. The advantages of using Silica Gel G powder for latent fingerprint visualization underscore its significance as an innovative technique in forensic science. The latent fingerprints were developed on each of the several substrates using Merck Specialties Private Limited’s white-coloured silica gel G powder. There are several techniques in the literature for creating latent fingerprints. The emergence of Silica Gel G powder in forensic science represents a significant breakthrough in the visualization of latent fingerprints. The process of using Silica Gel G powder for latent fingerprint visualization exemplifies the precision and attention to detail required in forensic investigations.

Effect-directed analysis of endocrine and neurotoxic effects in stormwater depending discharges

The investigation of pollutant inputs via stormwater runoff and subsequent effects in receiving waters is becoming increasingly urgent in view of climate change with accompanying extreme weather situations such as heavy rainfall events. In this study, two sampling areas, one urban and one rural but dominated by a highway, were investigated using effect-directed analysis to identify endocrine and neurotoxic effects and potentially responsible substances in stormwater structures and receiving waters. For this purpose, a transgenic yeast cell assay for the simultaneous detection of estrogenic, androgenic, and progestogenic effects (YMEES) was performed directly on high-performance thin-layer chromatography (HPTLC) plates. Concomitantly, estrogens were analyzed by GC–MS/MS and other micropollutants typical for wastewater and stormwater by LC-MS/MS. Discharges from the combined sewer overflow (CSO) contribute a large portion of the endocrine load to the studied water body, even surpassing the load from a nearby wastewater treatment plant (WWTP). An effect pattern similar to the CSO sample was shown in the receiving water after the CSO with lower intensities, consisting of an estrogenic, androgenic, and progestogenic effect. In contrast, after the WWTP, only one estrogenic effect with a lower intensity was detected. Concentrations of E1, 17α-E2, 17β-E2, EE2, and E3 in the CSO sample were 2000, 410, 1100, 560, and 2700 pg/L, respectively. HPTLC-YMEES and GC–MS/MS complement each other very well and help to elucidate endocrine stresses. An Acetylcholinesterase (AChE) inhibitory effect could not be assigned to a causative compound by suspect and non-target analysis using LC-HRMS. However, the workflow showed how information from HPTLC separation, effect-based methods, and other meta-information on the sampling area and substance properties can contribute to an identification of effect-responsible substances. Overall, the study demonstrated that effect-based methods in combination with HPTLC and instrumental analysis can be implemented to investigate pollution by stormwater run-off particularly regarding heavy rain events due to climate change.

Thin layer chromatography assay to detect laccase inhibitors

Thin-layer chromatography (TLC) hyphenated to bioassays is a modern tool used for discovery of biologically active compounds from complex mixtures. The first bioautographic assay for detecting laccase inhibitors on a TLC plate was developed in this study. The on-plate reaction of laccase with colourless ABTS that renders the blue ABTS∙+ radical was optimised. Combination of the enzymatic TLC-assay with a control TLC-assay, wherein ABTS∙+ radical is chemically generated and then applied on the TLC, allowed to differentiate between the pure laccase inhibitor sodium azide and radical scavengers such as gallic and kojic acids. The limit of detection and quantification for the method were 54.9 and 166 ng of sodium azide respectively. The methodology was applied successfully to a recently discovered laccase inhibitor chemotype: hydrazones. A model hydrazone was compared with several hydrazones synthesized for this study. For the first time, laccase inhibitors separated on a TLC plate can be detected individually.

Smartphone-based detection and discrimination of amine vapors by a single dye-adsorbed material

Smartphone-assisted analysis has become widely utilized for detecting various species in recent years. In such studies, multiple dyes should be employed to ensure selectivity and analyte discrimination. In our research, we have demonstrated the capability of a specially synthesized dye to selectively detect and discriminate liquid amine vapors. The developed material employs meso-toluene-α,β,α’,β’-tetrabromoBODIPY immobilized on a thin-layer chromatography plate, exhibiting structure-specific color changes in response to amine vapors. The hue values of these colors, observed under both ambient and UV light, enable discrimination even among closely related amine structures. A mobile application has also been developed for the rapid interpretation of test results.

Antiparasitic Activity of Isolated Fractions from Parthenium incanum Kunth against the Hemoflagellate Protozoan Trypanosoma cruzi.

This study focused on isolating, identifying, and evaluating the trypanocidal potential against the hemoflagellate protozoan Trypanosoma cruzi of compounds from Parthenium incanum (Mariola), a plant used in traditional Mexican medicine to treat stomach and liver disorders. P. incanum has a wide distribution in Mexico. This study found that methanolic extracts of P. incanum, obtained by static maceration and successive reflux, had promising results. The fractions were compared using thin-layer chromatography (TLC) and those that showed similarities were mixed. A bioguided assay was performed with Staphylococcus aureus ATCC 25923, using agar diffusion and bioautography techniques to determine the preliminary biological activity. The fractions with antimicrobial activity were purified using a preparative thin-layer chromatography (PTLC) plate, obtaining the bioactive bandages that were subjected to a trypanocidal evaluation against the Ninoa strain of T. cruzi in its epimastigote stage. This revealed an IC50 of up to 45 ± 2.5 µg/mL, in contrast to the values obtained from the crude extracts of less than 100 µg/mL. The TLC, Fourier-transform infrared spectroscopy (FT-IR), and high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) techniques were used to identify the compounds, demonstrating the presence of sesquiterpene lactones, parthenin, and coronopolin. We concluded that these compounds have the potential to inhibit T. cruzi growth.

Method development and validation for quantification of Yohimbine in root of Rauwolfia serpentina by HPTLC

Plants are a priceless and vital resource that give us medicine, food, fibre, and all other necessities. The evergreen shrub, Rauwolfia serpentina (L.) Benth. ex Kurz., also known as Indian snakeroot, sarpagandha is a member of the Apocynaceae family. Rauwolfia serpentina has fewer negative effects and an abundance of phytochemicals in the roots and leaves of the plant, it shows a wide range of therapeutic activity. With the goal of developing a densitometric high-performance thin-layer chromatography (HPTLC) method, in order to quantify Yohimbine hydrochloride in Rauwolfia roots, it will help to insure the collection and harvesting time. The five distinct brands of market Rauwolfia root samples are compared with in-house samples prepared in the laboratory. The silica gel 60 F254 high-performance thin-layer chromatography plates were used with toluene, Toluene : Ethyl acetate : Diethylamine (7:1.5:1.5 v/v/v) as a mobile phase. The validation parameters for the developed method were carried out as per the International Conference on Harmonisation (ICH) guideline Q2 (R1). The calibration curve was found to be linear over a range of 1-7 μg/spot for yohimbine. The method involves densitometric detection at 280 nm. The relative standard deviations (RSD) for precision were found to be lower than 2% for both analytes. Percent recoveries for accuracy were performed and found to be 98.5-99.98% for yohimbine, The LOD and LOQ for Yohimbine were 0.08 μg/ml and 0.24 μg/ml, respectively. Validation parameters were carried out as per International Conference on Harmonisation (ICH) guideline Q2 (R1). The Rf value of 0.64 have been observed for Yohimbine. This HPTLC densitometric method is highly suitable for the analysis of Yohimbine present in the dosage of marketed herbal products of sarpagandha root without any interference.

Molecular Docking, Synthesis, Antiproliferative Activity against MCF-7, and In-vitro Alpha Amylase Activities of Newer Generation Pyrimidino Hydroxamic Acid Derivatives

A set of newer generation pyrimidine hydroxamic acid derivatives were designed, synthesized, and evaluated for antiproliferative activity against breast cancer cell line and in-vitro alpha-amylase activity. The design of the molecules was fully dependent upon the structural features of suberoyl anilide hydroxamic acid. Then all the designed molecules (S1-S100) were docked with 4LXZ HDAC2 enzyme and S1, S2, S16 showed good docking interaction scores as compared to SAHA. The interacting residues of (S1, S2, S16) and 4LXZ showed similar amino acid lining as present in the active site. The synthetic procedure of the molecules (S1, S2, S16) was divided into three parts such as synthesis of chalcone derivative using aromatic aldehyde and acetophenone, the reaction between chalcone and thiourea to form substituted pyrimidine-2-thiol, then finally substituted pyrimidine-2-thiol and 2-chloro-N-hydroxyacetamide reacted in the presence of dimethylformamide to obtain the best-docked molecules. All the molecules showed characteristic peaks in fourier-transform infrared (FTIR), proton nuclear magnetic resonance (1H-NMR) and mass spectrometry with sharp melting points and single peak in thin layer chromatography (TLC) plate. Finally antiproliferative activity against MCF-7 and in-vitro alpha amylase activity data confirmed that S1 was the best molecule among all the synthesized molecules.

Two protocols for the detection of oleaginous bacteria using Oil Red O

The selection of oleaginous bacteria, potentially applicable to biotechnological approaches, is usually carried out by different expensive and time-consuming techniques. In this study, we used Oil Red O (ORO) as an useful dye for staining of neutral lipids (triacylglycerols and wax esters) on thin-layer chromatography plates. ORO could detect minimal quantities of both compounds (detection limit, 0.0025 mg of tripalmitin or 0.005 mg of cetylpalmitate). In addition, we developed a specific, rapid, and inexpensive screening methodology to detect triacylglycerol-accumulating microorganisms grown on the agar plate. This staining methodology detected 9/13 strains with a triacylglycerol content higher than 20% by cellular dry weight. ORO did not stain polyhydroxyalkanoates-producing bacteria. The four oleaginous strains not detected by this screening methodology exhibited a mucoid morphology of their colonies. Apparently, an extracellular polymeric substance produced by these strains hampered the entry of the lipophilic dye into cells. The utilization of the developed screening methodology would allow selecting of oleaginous bacteria in a simpler and faster way than techniques usually used nowadays, based on unspecific staining protocols and spectrophotometric or chromatographic methods. Furthermore, the use of ORO as a staining reagent would easily characterize the neutral lipids accumulated by microorganisms as reserve compounds.Key points• Oil Red O staining is specific for triacylglycerols• Oil Red O staining is useful to detect oleaginous bacteria• Fast and inexpensive staining to isolate oleaginous bacteria from the environment

Continuous stationary phase gradient preparation on planar chromatographic media using vapor phase deposition of silane

A new, versatile, and straightforward vapor phase deposition (VPD) approach was used to prepare continuous stationary phase gradients (cSPGs) on silica thin-layer chromatography (TLC) plates using phenyldimethylchlorosilane (PDCS) as a precursor. A mixture of paraffin oil and PDCS was placed at the bottom of an open-ended rectangular chamber, allowing the reactive silanes to evaporate and freely diffuse under a controlled atmosphere. As the volatile silane diffused across the length of the TLC plate, it reacted with the surface silanol groups thus functionalizing the surface in a gradient fashion. Characterization of the gradient TLC plates was done through UV visualization and diffuse reflectance spectroscopy (DRS). Visualizing the fluorescent gradient plates under UV radiation shows the clear presence of a gradient with the side closest to the vapor source undergoing the most modification. More quantitative characterization of the shape of the gradient was provided by DRS. The DRS showed that the degree of modification and shape of the gradient was dependent on the concentration of silane, VPD time, and relative humidity. To evaluate the chromatographic performance, a mixture of three aromatic compounds (acetaminophen (A), aspirin (As), and 3-hydroxy-2-naphthoic acid (3H)) was spotted on the high (GHP) and low phenyl (GLP) ends of the gradient TLC plates and the results compared to the separations carried out on unmodified and uniformly modified plates. The GHP TLC plates showed retention factors (Rf) of 0.060 ± 0.006, 0.391 ± 0.006, and 0.544 ± 0.006, whereas the unmodified plate displayed Rf values of 0.059 ± 0.006, 0.092 ± 0.003, and 0.037 ± 0.002 for the analytes A, As, and 3H, respectively. From the Rf values, it was observed that each modified plate exhibited different selectivity for the analytes. The GHP TLC plates exhibited better separation performance, and improved resolution compared to the GLP, unmodified, and uniformly modified plates. Overall, VPD is a new, cost-effective method for creating a gradient on the stationary phase which has the potential to advance chromatographic separation capabilities.

Ultrafast Solid-Phase Oxidation of Aldehydes to Carboxylic Acids by Atmosphseric Plasma Treatment.

Although atmospheric plasma treatment is an industrially widespread, scalable, and environmentally friendly method, it has been generally used for surface modification, decontamination, or sterilization. In this paper, a novel, sustainable, green, and ultrafast oxidation method is described for aldehydes on a preparative thin-layer chromatographic plate as a solid support. The plasma treatment has proven to be suitable for producing the corresponding carboxylic acids by using only air as a reactant source under mild reaction conditions, while the isolation of the products is also directly integrated into the oxidation process. Extensibility to other reaction types is not explored yet, but we are sure that this novel synthesis conception carries a lot of possibilities.

Comparison of the Limit of Detection of Paracetamol, Propyphenazone, and Caffeine Analyzed Using Thin-Layer Chromatography and High-Performance Thin-Layer Chromatography

TLC (thin-layer chromatography) and HPTLC (high-performance thin-layer chromatography) in normal (NP) and reversed (RP) phase systems were combined with densitometry to analyze caffeine, propyphenazone, and paracetamol. This work aims to check whether comparable limit of detection (LOD) values can be obtained on TLC and HPTLC plates. Analyses were performed on five (NP) or four (RP) different stationary phases (chromatographic plates), testing, in both cases, three mobile phases. It is shown that by using both TLC and HPTLC plates, it is possible to develop chromatographic conditions that enable the detection of compounds analyzed in amounts ranging from a dozen to several dozen µg/spot. In the RP system, lower LOD values for all tested compounds were obtained using TLC than HPTLC. However, performing analyses in the NP, similar (of the same order) LOD values were obtained for caffeine, propyphenazone, and paracetamol when using both TLC and HPTLC plates. For example, during the NP-HPTLC analysis using silica gel 60F254 plates (#1.05548) and mobile phase B (n-hexane—acetone—ammonia, 25:25:0.5, v/v/v), LOD values for caffeine, propyphenazone, and paracetamol were 0.010, 0.046, and 0.030 μg/spot, respectively. During NP-TLC analysis using silica gel 60F254 (#1.05554 plates) and the mobile phase C (chloroform—toluene—ethyl acetate—methanol—80% acetic acid, 18:18:7.5:6:0.3, v/v), the values of LOD were 0.054, 0.029, and 0.016 μg/spot, respectively. During RP-TLC analysis using TLC RP-18F254 plates (#1.05559) and mobile phase F (methanol-water, 40:10, v/v), the LOD values were 0.019, 0.024, and 0.053 μg/spot, respectively. Therefore, for economical reasons, TLC plates should be recommended for analyses of caffeine, propyphenazone, and paracetamol, which are several times cheaper than HPTLC plates.

Extraction and Purification of Squalene from Virgin Olive Oil via Catalytic Transesterification and Molecular Distillation

Squalene, a highly valuable compound abundant in various natural sources, shows great potential in pharmaceutical, cosmetic, and nutraceutical applications. This research article outlines a comprehensive methodology for extracting and purifying squalene from virgin olive oil, a rich source of the compound. The extraction process begins with degumming, which involves heating the olive oil to 60-70°C to reduce viscosity, followed by the addition of 2-3% warm water to hydrate phospholipids. Food-grade phosphoric acid is then added to react with the phospholipids, forming precipitates. The mixture is stirred for 20-30 minutes and allowed to rest for an additional 20-30 minutes, enabling impurities to settle. The upper layer of degummed oil is separated via decantation or centrifugation and washed with warm water for pH adjustment. Next, transesterification is performed by mixing 100 ml of virgin olive oil with 25% methanol (w/w) and a catalyst (0.5% sodium methoxide or PTSA), and heating the mixture to 80-90°C under reflux for 1-2 hours. Following transesterification, the solvent and acetone are distilled out, and acetone precipitation is repeated 2-3 times to remove unsaponified matter, which is then filtered and evaporated. The concentrated oil undergoes molecular distillation at 180°C and 0.0033 bar pressure for 1 hour, yielding the distillate and residue for further analysis. Qualitative analysis using Thin Layer Chromatography (TLC) involves Merck TLC plates with silica gel 60 F254 and a hexane: chloroform (9:1) mobile phase. Spots are developed with a 10% HCl solution, confirming the presence of squalene with an RF value of 0.93. Quantitative analysis via High-Performance Thin-Layer Chromatography (HPTLC) employs Merck TLC plates with cyclohexane as the mobile phase and CAMAG at 254 nm and 366 nm wavelengths, revealing a squalene purity of 67% and a recovery rate of 69.8%. The initial purification through transesterification facilitated the conversion of ester groups, yielding squalene-rich fractions, while acetone precipitation effectively removed saponified matter. Molecular distillation further enhanced squalene purity. TLC analysis confirmed the qualitative presence of squalene, and HPTLC provided precise quantitative measurements. The obtained squalene purity of 67% significantly enriches the initial content in virgin olive oil, though further optimization could enhance purity and yield. Complementary techniques like GC-MS or HPLC could validate the purification process. This study presents an efficient, replicable procedure for extracting and purifying squalene from virgin olive oil, with significant implications for pharmaceutical, cosmetic, and nutraceutical industries. The findings support a sustainable and ethical shift towards vegetable-derived squalene, meeting market demands while ensuring high-quality production.

Automated identification of pesticide mixtures via machine learning analysis of TLC-SERS spectra

Identification of components in pesticide mixtures has been a major challenge in spectral analysis. In this paper, we assembled monolayer Ag nanoparticles on Thin-layer chromatography (TLC) plates to prepare TLC-Ag substrates with mixture separation and surface-enhanced Raman scattering (SERS) detection. Spectral scans were performed along the longitudinal direction of the TLC-Ag substrate to generate SERS spectra of all target analytes on the TLC plate. Convolutional neural network classification and spectral angle similarity machine learning algorithms were used to identify pesticide information from the TLC-SERS spectra. It was shown that the proposed automated spectral analysis method successfully classified five categories, including four pesticides (thiram, triadimefon, benzimidazole, thiamethoxam) as well as a blank TLC-Ag data control. The location of each pesticide on the TLC plate was determined by the intersection of the information curves of the two algorithms with 100 % accuracy. Therefore, this method is expected to help regulators understand the residues of mixed pesticides in agricultural products and reduce the potential risk of agricultural products to human health and the environment.

Quantification of isoniazid in tablets for tuberculosis treatment by thin layer chromatography with smartphone image capture and ImageJ analysis

Isoniazid (INH) oral dosage tablets are an antibacterial medication commonly used to treat tuberculosis (TB). While this medication can be highly effective in managing and curing TB, manufacturing of poor-quality INH products can lead to the proliferation of drug resistant TB strains – particularly in low- and middle-income countries (LMICs). It is therefore imperative that reliable methods of quality screening of INH tablets are available for areas that have limited access to traditional testing resources. In this study, a thin layer chromatography (TLC) procedure for INH identification is validated in conjunction with smartphone image capture and open-source image analysis software to provide an alternative quantitative quality screening method for INH tablets, primarily intended for applications in LMICs. The method assessed two individual tablet formulations: 100 mg and 300 mg INH, each from different manufacturers. The modified TLC procedure used for the study was based on a validated high-performance thin layer chromatography method for the determination of rifampicin, INH, and pyrazinamide in a fixed dosage tablet. Quantitation was performed by visualizing and photographing TLC plates using a UV lamp, 3D-printed light box, and Apple iPhone SE 2nd Generation (2020) and Google Pixel 4a (5G) smartphones, and images were then analyzed using ImageJ Fiji software. The processed images’ pixel data were used to create a calibration curve from the INH standard spots to determine the concentration of an INH sample spot. Linearity, range, accuracy, repeatability and intermediate precision, specificity, and robustness were evaluated. The method was linear in the range of 0.150–0.450 mg mL−1, with coefficients of determination ≥0.98. The overall accuracy of the method was 99.2 % with an RSD of 2.4 % for image sets captured using the Apple iPhone, and 99.7 % with an RSD of 3.3 % for image sets captured using the Google Pixel. The pooled standard deviations for repeatability and intermediate precision were 2.27 % and 3.25 %, respectively, for the iPhone and 2.62 % and 3.74 %, respectively, for the Pixel. The method demonstrated sufficient specificity and robustness. The results of this method validation suggest that this procedure may provide a feasible alternative to traditional testing as a low-cost means of quality screening in LMICs.

Intermolecular π-π interactions-induced aggregation based on bispyrene for ultrasensitive detection of picric acid (PA) and 2,4-dinitrophenol (DNP)

It was still important to explore excimer emission-based fluorescence probes for nitroaromatics detection by formation or destruction of pyrene excimer with strong emission change. In this work, we have synthesized a simple bis(pyrene) derivative (BisPyH) and studied its optical behavior by using UV–vis and fluorescent spectroscopy. In pure DMSO solution, it emitted a weak blue fluorescence due to the formation of excimer states, on the contrary, the BisPyH in the DMSO/H2O (v/v, 1:1) mixture solution was self-assembled to form aggregates via intermolecular π-π interactions among pyrene units, giving almost 10-fold fluorescence enhancement compared to that in pure DMSO solution. The formed aggregates just offered a perfect platform for the selective detection PA and DNP explosives by quenching the bright green intermolecular-excimer emission in competitive environment. BisPyH exhibited a limit of detection (LOD) towards PA, and DNP as low as 7.32 × 10−8, and 8.11 × 10−8 M, respectively. Subsequently, the fluorescence quenching mechanism was demonstrated by the density functional theory (DFT), UV–vis and fluorescence spectra, SEM, and the quenching constants. Furthermore, filter paper strips and thin-layer chromatography (TLC) plates coated with BisPyH were able to detect PA and DNP in the practical application.

Development and validation of a quantitative minilab system for quality evaluation of selected medicines: Albendazole, arthemether-lumefantrine combination (Co-artem®), and mebendazole finished pharmaceutical products

AbstractThe current technologies for substandard and counterfeit drug detection are either too expensive for low-resource settings or only provide qualitative or semi-quantitative results. GPHF minilab™ is one of them based on thin layer chromatography(TLC) principles with a semi-quantitative capability by visual observation of the spot area and intensity for medicine quality analysis. Thus, its use as a quality control tool for pharmaceutical products has limitations as spot area and intensity visual observation by the naked eye highly varies from analyst to analyst. As such, in this study, the semi-quantitative technique has been transferred to a quantitative approach by capturing the developed TLC plate image using an Android-based mobile phone inside a simple carton box. Then, the spot area was quantified using justTLC software. The quantitative results were compared with the-high performance liquid chromatography (HPLC) method as the golden standard. Accordingly, linearity was observed in the assayed range (80–120% label claim), and the correlation coefficients found were (R2 = 0.958, 0.997, 0.941, and 0.956 for Albendazole, Mebendazole, Artemether, and Lumefantrine, respectively.). The values are satisfactory. The %RSDs found were less than 2% for all drugs [intraday (n = 6) (RSD = 1.17, 1.61, 1.87, and 1.64), and interday (n = 18) (RSD = 1.16, 0.72, 1.12, and 1.18) for Artemether, Lumefantrine, Mebendazole, and Albendazole, respectively]. Moreover, comparisons of results obtained from the sophisticated CAMAG UV cabinet (R2 =0.991, 0.971, 0.946, and 0.967) and the developed simple carton box (R2 = 0.958, 0.997, 0.941, and 0.956) for Albendazole, Mebendazole, Artemether, and Lumefantrine, respectively. The values are comparable and reveal the accuracy of the method. Robustness testings' that were performed under different altered conditions revealed the robustness of the method (RSD less than 2% for all factors). Additionally the deviations from the golden HPLC results were on average −8.62% for albendazole, −3.79% for artemether, and −4.52% for lumefantrine samples. The developed method shows a satisfactory performance capability to utilize the GPHF minilab™ as a quantitative technique for medicine quality control purposes. It will be a very useful tool in a resource-limited setting. The target method profile, which encompasses a simple, low-cost, linear, precise, robust, accurate, and quantitative GPHF minilab™ system, was obtained for Albendazole, Mebendazole, and Arthemeter lumefantine combinations (Co-artem). The proposed method was successfully applied to analyze the content of the marketed medicines in the above mentioned tablets and offered acceptable deviations from the golden HPLC method. Automation of quantitative GPHF minilab™ was highly recommended to enhance the appropriateness and use of this system.

Detection of Tetrahydrocannabinol in Commercial Consumables: A Survey-Based Study with Real Time Samples

The study aimed to detect the presence of tetrahydrocannabinol (THC) in commercial consumables, specifically focusing on real-time samples. The study highlights the widespread use and cultivation of cannabis, with various compounds such as THC and Cannabidiol (CBD) present in the plant. THC is responsible for the psychoactive effects, while CBD is non-intoxicating and may have therapeutic benefits. The study also discusses the legal and social acceptance of cannabis across countries and regions. The study emphasizes the need for analysing street samples of pan-masala and other tobacco-containing orally consumable products for the presence of cannabis alkaloids, as they are often used as a concealment step for selling and purchasing cannabis. The experimental details include using chemicals and solvents from commercial sources, thin-layer chromatography (TLC) plates and an Ultraviolet-Visible spectrophotometer for detecting THC. The study used Dragendroff (DD) and Fast Blue B (FBB) reagents to identify THC. The THC quantities detected were 15.32 µM, 29.2 µM, 7.15 µM, and 5.3 µM respectively in the collected sample.