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The advantages of hyperspectral imaging in videodensitometry are presented and discussed with the example of extracts from 70 Polish grasses. An inexpensive microscope camera was modified to cover the infrared spectrum range, and then 11 combinations of illumination (254 nm, 366 nm, white light), together with various filters (no filter, IRCut, UV, cobalt glass, IR pass), were used to register RGB HDR images of the same plate. It was revealed that the resulting 33 channels of information could be compressed into 5–6 principal components and then visualized separately as grayscale images. We also propose a new approach called principal component artificial coloring of images (PCACI). It allows easy classification of chromatographic spots by presenting three PC components as RGB channels, providing vivid spots with artificial colors and visualizing six principal components on two color images. The infrared region brings additional information to the registered data, orthogonal to the other channels and not redundant with photos in the visible region. This is the first published attempt to use a hyperspectral camera in TLC and it can be clearly concluded that such an approach deserves routine use and further attention.

Favipiravir (FAV) has become a promising antiviral agent for the treatment of COVID-19. Herein, a green, fast, high-sample-throughput, non-instrumental, and affordable analytical method is proposed based on surfactant-assisted dispersive liquid–liquid microextraction (SA-DLLME) combined with thin-layer chromatography–digital image colourimetry (TLC-DIC) for determining favipiravir in biological and pharmaceutical samples. Triton X-100 and dichloromethane (DCM) were used as the disperser and extraction solvents, respectively. The extract obtained after DLLME procedure was spotted on a TLC plate and allowed to develop with a mobile phase of chloroform:methanol (8:2, v/v). The developed plate was photographed using a smartphone under UV irradiation at 254 nm. The quantification of FAV was performed by analysing the digital images’ spots with open-source ImageJ software. Multivariate optimisation using Plackett–Burman design (PBD) and central composite design (CCD) was performed for the screening and optimisation of significant factors. Under the optimised conditions, the method was found to be linear, ranging from 5 to 100 µg/spot, with a correlation coefficient (R2) ranging from 0.991 to 0.994. The limit of detection (LOD) and limit of quantification (LOQ) were in the ranges of 1.2–1.5 µg/spot and 3.96–4.29 µg/spot, respectively. The developed approach was successfully applied for the determination of FAV in biological (i.e., human urine and plasma) and pharmaceutical samples. The results obtained using the proposed methodology were compared to those obtained using HPLC-UV analysis and found to be in close agreement with one another. Additionally, the green character of the developed method with previously reported protocols was evaluated using the ComplexGAPI, AGREE, and Eco-Scale greenness assessment tools. The proposed method is green in nature and does not require any sophisticated high-end analytical instruments, and it can therefore be routinely applied for the analysis of FAV in various resource-limited laboratories during the COVID-19 pandemic.

Background Modafinil (MDF) is one of the drugs used for the treatment of narcolepsy. Objective This manuscript describes the development and validation of two chromatographic stability-indicating methods for MDF in the presence of its acid-induced degradation product. Methods MDF was degraded under different stress conditions and identification of the degradation product was performed using IR and mass spectroscopy. The first method involved TLC, in which plates precoated with silica gel G60 F254 were used and the developing system was dichloromethane– methanol (9:1, v/v). The second method was an eco-friendly (HPLC) method that utilized a C-18 column and ethanol–H2O (30:70, v/v) as a mobile phase with a flow rate of 1 mL/min and UV detection at 220 nm. Results Good linear relationships were obtained within the ranges 1–10 µg/band and 2–10 µg/mL for TLC–densitometry and HPLC, respectively. The obtained results were statistically compared with those of the official HPLC method and showed no significant difference with respect to their accuracy and precision at P = 0.05. Greenness scores represent excellent green analysis results in comparison with the reported studies. Conclusions The proposed methods were validated according to ICH guidelines and were applied on bulk powder and pharmaceutical dosage forms using eco-friendly mobile phases in line with worldwide trends. Highlights Chromatographic methods have been validated for the estimation of MDF in the presence of its degradation product. Clarification of the degradation pathway and elucidation of the structure were stated for the first time. This is the first published method using greenness assessment metrics for the analysis of MDF.

Background Nanocolloidal human serum albumin radiolabelled with 99mTc provides a diagnostic radiopharmaceutical for sentinel node lymphoscintigraphy. NanoHSA (Nanotop), a commercially available kit, enables the simple preparation of this radiopharmaceutical via reconstitution with pertechnetate eluted from a generator. Thin-layer chromatography is widely used for determining radiochemical purity in clinical nuclear medicine. Quality control methods recommended by the manufacturer were sometimes reported to yield variable results. Therefore, we proposed and evaluated three alternative thin-layer chromatography methods for the quality control of [99mTc]Tc-NanoHSA from a commercially available kit. Results The radiochemical purity of [99mTc]Tc-NanoHSA determined with all methods was reproducible and met the requirements of the SPC and the European Pharmacopoeia (≥ 95%). Our quality control using iTLC-SG chromatographic paper in methyl ethyl ketone mobile phase identified only free pertechnetate as impurity, resulting in > 99% RCP. The quality control using iTLC-SG in 85% methanol or iTLC-SA in 0.9% NaCl identified an additional small fraction of a hydrophilic impurity, resulting in 95–97% RCP. Glucose was identified as a potential 99mTc-carrying hydrophilic species contributing to hydrophilic impurities. Conclusion Our quality control of [99mTc]Tc-NanoHSA with non-polar mobile phase tended to underestimate the amount of hydrophilic impurities, although without compromising the final quality of the radiopharmaceutical. Alternative TLC methods using aqueous mobile phases enabled a more accurate determination of hydrophilic impurities.

Brazilin, a constituent of the Chinese medicine heartwood, exhibits pronounced anti-tumor effects. To date, brazilin quantification mostly relies on high-performance liquid chromatography (HPLC), which is not accurate enough because of an easily oxidizable structure. Herein, a thin-layer chromatography (TLC)-based method was developed for the quantitative analysis of brazilin. A water solution of purified brazilin was spotted on a GF254 silica gel plate and developed using a mixture of chloroform‒acetone‒formic acid (8:4:1, V/V). After ammonia vaporing, AlCl3 solution (90 mg/mL) was sprayed to form a stable compound. Detection was performed at 508 nm using a dual-beam TLC scanner, and brazilin was quantitatively analyzed by using an external standard. The optimal time for ammonia vaporing was 6 min. Sample stability remained for 10‒200 min. At 508 nm, brazilin absorbance showed a good linear relationship in the range of 0‒6 μg (R2 = 0.9962). Precision RSD was no more than 3.40%, and recovery was between 100 and 105%. This novel TLC-based method has great potential for the quantitative assessment of brazilin. It is simpler, more reliable, and faster than HPLC-based analysis.

The aim of this work is to develop a device based on thin-layer chromatography coupled with surface-enhanced Raman spectroscopy (TLC-SERS) to analyze sulfamethoxazole (SMX) and trimethoprim (TMP) in commercial milk samples using chemometric tools. Samples were eluted in TLC plates, and a central composite design (CCD) of two factors was performed to optimize the gold nanoparticle dispersion on TLC plates for SERS, aiming at the detection of both drugs at concentrations close to their maximum residual limits (MRLs). Following the optimization, hyperspectral images from the SERS were captured of the TLC plates. Multivariate curve resolution (MCR-ALS) and independent component analysis (ICA) chemometric techniques were used to extract the signals of the analytes. All the samples presented recovery values of 81–128% for TMP. The quantification of SMX was not possible due to SERS suppression by an interferent. However, it was possible to detect SMX at a concentration of two times the MRL (8.0 × 10−7 mol·L−1). The results demonstrate that the TLC-SERS device is a potential tool for the quantification of TMP and the detection of SMX in milk.

Before formulating radiopharmaceuticals for injection, it is necessary to remove various impurities via purification. Conventional synthesis methods involve relatively large quantities of reagents, requiring high-resolution and high-capacity chromatographic methods (e.g., semi-preparative radio-HPLC) to ensure adequate purity of the radiopharmaceutical. Due to the use of organic solvents during purification, additional processing is needed to reformulate the radiopharmaceutical into an injectable buffer. Recent developments in microscale radiosynthesis have made it possible to synthesize radiopharmaceuticals with vastly reduced reagent masses, minimizing impurities. This enables purification with lower-capacity methods, such as analytical HPLC, with a reduction of purification time and volume (that shortens downstream re-formulation). Still, the need for a bulky and expensive HPLC system undermines many of the advantages of microfluidics. This study demonstrates the feasibility of using radio-TLC for the purification of radiopharmaceuticals. This technique combines high-performance (high-resolution, high-speed separation) with the advantages of a compact and low-cost setup. A further advantage is that no downstream re-formulation step is needed. Production and purification of clinical scale batches of [18F]PBR-06 and [18F]Fallypride are demonstrated with high yield, purity, and specific activity. Automating this radio-TLC method could provide an attractive solution for the purification step in microscale radiochemistry systems.

Background Validated ultra-performance liquid chromatography (UPLC) and thin-layer chromatography (TLC) densitometric methods were prescribed for determination of antihypertensive components. Objective To establish and validate rapid and accurate UPLC and TLC densitometric methods for determination of Xipamide and Triamterene in pure and dosage forms. Methods The first method, UPLC, depended on using an Agilent Zorbax Eclipse Plus C8 (50 mm × 2.1 mm, 1.8 μm) column, a mobile phase composed of acetonitrile-water (70 + 30, v/v) adjusted by acetic acid to obtain pH 3, 0.2 mL/min flow rate, and UV detection at 231.4 nm. The second method was a TLC densitometric method. Separation was achieved by using toluene-methanol-ethyl chloride-acetic acid (7 + 2 + 1 + 0.2, v/v/v) as the mobile phase, pre coated silica gel plates as the stationary phase, and UV detection at 300.0 nm. Results The obtained results were validated and statistically compared with official and reported methods. The obtained results showed high accuracy and reproducible results with excellent mean recoveries for both drugs. Conclusion The UPLC method showed shorter retention time for both Xipamide (0.88 min) and Triamterene (0.63 min), a lower detection limit of less than 0.055 µg/mL for both drugs with high selectivity, decreased injection volume (1 µL), and a lower flow rate than any HPLC method. Both proposed methods were sensitive, selective, and effectively applied to pure and dosage forms (Epitens®). Highlights Unprecedented sensitive, rapid, and reproducible UPLC and TLC methods were developed for selective determination of mixtures of Xipamide and Triamterene, with LOD os less than 0.076 µg/mL for both drugs.

Fast, cheap, and simple separation of lipids and hydrocarbons can currently be achieved using thin-layer chromatography. Here, we describe an alternative planar chromatographic method using polyvinylidene difluoride membranes as the stationary phase. The procedure has the same advantages of thin-layer chromatography over other expensive and time-consuming techniques, such as high-performance liquid chromatography or gas chromatography. Polyvinylidene difluoride membranes, however, also provide an immediate support for analyte development via immunodetection, are easy to manipulate, and potentially increase the performance of other detection methods. We show that polyvinylidene difluoride membranes are compatible with a variety of solvents that can migrate by capillarity and redistribute analytes between the membrane and the solvent according to their relative affinities, providing a chromatographic separation. We directly test the developed membranes by immunoblotting using anti-squalene antibodies that cross-react with acyclic isoprenoids. Separations of crude oils and plant extracts under different solvent conditions show the potential to resolve hydrocarbon group types and also to provide characteristic fingerprints of plant pigments and squalene degradation products. Polyvinylidene difluoride membranes prove useful as a stationary phase for planar chromatography and for the subsequent immunodetection of the separated compounds, providing a new and simple chromatographic technique to analyze lipids and hydrocarbons.

Chromatography is one of the most popular methods for the separation of compounds in modern pharmaceutical industry and science. Despite the extensive use of the reversed phase chromatography in analytical and preparative applications, the normal phase adsorption chromatography has a special place in purifying post-reaction mixtures or the separation of natural extracts, especially in wet load mode, because of simplicity and high velocity of preparation. Complex mixtures, more difficult to separate, require gradient methods to obtain better results of separations. These methods can be developed by external software, but the automatic methods are often not very accurate and the negative impact of wet load application on separation quality is considerable in them. Therefore, we present the thin-layer chromatography (TLC) gradient optimization strategy for wet load separations to obtain repeatable results of separations for different compounds without worrying about negative impact of wet loading on separation quality. The strategy provides information about an elution model of desired compound, which is used to develop the gradient method. The strategy also allows to standardize the separation length, because gradient methods performed by the TLC gradient optimization strategy have a very similar duration time in column volumes. The method can also be simply scaled because of using the column volume as a base unit in calculations.

The search for new anti-inflammatory drugs with less side effects requires simple, fast and reliable screening methods. In this context, we have developed a sensitive thin-layer chromatographic (TLC) assay on silica gel plates to detect cyclooxygenase-2 (COX-2) inhibition. COX-2 catalyzes two sequential enzymatic reactions: a first oxygenation step that converts arachidonic acid into prostaglandin G2, and a subsequent reduction of prostaglandin G2 into prostaglandin H2. Our test is based on the co-oxidation during this peroxidation step of a co-substrate, N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), leading to a blue-grey product. As a consequence, COX-2 inhibitors appear on the TLC plate after revelation as clear spots against the colored background. Parameters such as concentrations of enzyme, substrate, and chromogenic reagent have been optimized. The limit of detection was found to be below the microgram for standard COX-2 inhibitors such as celecoxib or ibuprofen. The developed TLC assay was also conclusive when applied to 60 various natural pure compounds and some complex natural extracts. Results demonstrated a COX-2 inhibitory activity mostly for triterpene and sterol derivatives. This COX-2 TLC assay appears as a suitable low-cost and reliable strategy for the screening of natural extracts to discover new anti-inflammatory compounds.

We investigated the dual retention mechanism in thin-layer chromatography taking place on three stationary phases of different polarity (C-18, plain silica gel and DIOL) and using binary mobile phases composed of acetonitrile as the main component and water, or methanol as a modifier. As the test analytes, we selected a set of 12 compounds of pharmaceutical importance and considerably different chemical structure, i.e. the imidazoline and serotonin receptor ligands, and their related compounds. Retention of each analyte in each investigated chromatographic system was determined in a wide enough range of the mobile phase composition, with volume fraction of the mobile phase modifier ranging from 0.10 to 0.90. Calculation of the exact turning point values as a proof of occurrence of the reversed-phase hydrophilic interaction chromatography (HILIC/RP) retention mechanism was based on the multimodal retention model. The dual retention mode was described with the use of the volume fraction of the mobile phase modifier, the total polarity and the total solubility models. For the DIOL, C-18 and silica gel stationary phase, the dual (HILIC/RP) retention mechanism was confirmed. In the case of the DIOL stationary phase and acetonitrile/methanol mobile phase, the observed retention mechanism was more complicated than the dual HILIC/RP one.

A simple and rapid high-performance thin-layer chromatography (HPTLC) assay was developed and validated for the quantification of tacrolimus ointments on silica gel 60 F254 HPTLC plates, using toluene–acetonitrile–ethyl acetate–glacial acetic acid (6:2:2:0.1, V/V) as the mobile phase and p-anisaldehyde‒sulphuric acid as the derivatising reagent. The analysis was performed at 366 nm. The method was fully validated according to the International Council for Harmonisation guidelines and found to be sensitive, precise, accurate and reproducible with tacrolimus presenting as a sharp band at RF 0.20, good linear regression between 20 and 140 ng/band (r2 = 0.9989) and sensitivity levels in terms of limit of detection and limit of quantification of 5.68 ng and 17.20 ng, respectively. The method is therefore deemed suitable for the routine quality control analysis of tacrolimus ointments.

Background Diflunisal (DIF) has analgesic and anti-inflammatory activity. It is a pharmacopeial drug found in the British Pharmacopoeia (BP), and its major pharmacopeial impurity is biphenyl-4-ol (BPL). Objective DIF has not previously been determined together with BPL. The presence of BPL could significantly affect the dose of DIF in its dosage forms; hence it is crucial to determine DIF and BPL in each other’s presence. Methods TLC is the first proposed method, where DIF and BPL were separated on silica gel TLC F254 plates. The eluent was toluene–acetone–acetic acid solution (3.5:6.5:1, v/v). Reversed-phase (RP) HPLC is the second suggested method, where a mixture of DIF and BPL was separated on a C18 (5 µm ps, 250 mm and 4.6 id) column using phosphate buffer pH 4 (0.05 M)–acetonitrile (40:60, v/v). Detection was carried out at 254 nm in both methods. Results For the TLC method, concentration ranges of 0.5–3 and 0.3–1.7 µg/band were used, with mean percentage recoveries of 100.22% (SD 0.893) and 100.52% (SD 0.952) for DIF and BPL, respectively. The RP-HPLC method was carried out over a concentration range of 5–30 and 2–9 μg/mL, with mean percentage recoveries of 100.10% (SD 1.259) and 98.88% (SD 0.822) for DIF and BPL, respectively. Conclusion The TLC and RP-HPLC methods were successfully applied for the determination of DIF and BPL, quantitatively, whether in bulk powder or in pharmaceutical formulations. Highlights Two chromatographic methods were developed and validated according to International Council on Harmonization guidelines for the assay of DIF and its pharmacopeial impurity.

Developing fit-to-purpose analytical screening methods for plant marker constituents by simple and affordable techniques represents a constant and important request from the current transformation chain of plant products. In this work, methods developed on classical thin-layer chromatography (TLC) and overpressured layer chromatography (OPLC) have been applied on some of the most valuable commercial plant products, such as star anise (Illicium verum Hook. f.) essential oil and extracts, common thyme (Thymus vulgaris L.) and sweet fennel (Foeniculum vulgare Mill.) essential oils and acerola fruit (Malpighia punicifolia L.) hydroalcoholic extracts, to evaluate OPLC potentiality in comparison with TLC performances in the detection of some characteristic constituents. OPLC provided higher performance with respect to TLC in all experiments performed due to higher selectivity demonstrated on all the tested marker compounds except for flavonoids in acerola extracts. Considering the usage of planar chromatography in the quality control of plant derivatives, the present paper shows how the OPLC protocols were both highly time- and solvent-saving in comparison with classical TLC.

A simple thin-layer chromatography (TLC)–densitometric and a TLC–image analysis method were developed for the quantitative determination of an active ingredient, genistein-7-O-[α-rhamnopyranosyl-(1 → 6)]-β-glucopyranoside (GTG) in Derris scandens, by using GTG and genistein as reference standards. Due to a large polarity difference between GTG and genistein, chromatographic analysis was achieved on a silica gel 60 F254 TLC plate using a multiple development technique, with ethyl acetate–methanol–water (8:1.3:1, V/V) and n-hexane–ethyl acetate (6:4, V/V) as the first and the second mobile phase, respectively. The method was validated and applied for the determination of GTG in D. scandens. The analytical results obtained from the TLC–densitometric, TLC–image analysis and HPLC methods were compared and found to be not significantly different.

Two simple, sensitive, and reproducible methods were developed for the determination of alogliptin and metformin hydrochloride in presence of metformin impurity "melamin" in pure form and in pharmaceutical formulation. Method (A) was a thin layer chromatographic method in which separation was achieved using ethyl acetate-methanol-formic acid (6:3.8:0.2, by volume) as a developing system followed by densitometric scanning at 230 nm. Method (B) was a high-performance liquid chromatography method; separation was achieved on C18 column, the mobile phase consisted of a mixture of sodium lauryl sulfate buffer 0.1% w/v, pH 3: methanol in the ratio 70:30, v/v and measurement was done at 220 nm. System suitability testing parameters were calculated to ascertain the quality performance of the developed chromatographic methods. The proposed methods have been validated regarding accuracy, precision, and selectivity, moreover they have been successfully applied to Westirizide tablets containing both alogliptin and metformin hydrochloride, results indicate that there was no interference from additives. No significance difference was found when these methods were compared to the reported one.

Volatile organic solvents being generally hazardous to human beings, impact environment and hence are being replaced by environmentally eco-friendly solvents in analytical chemistry. Use of green solvents in different technologies has gained popularity in order to make environment free from pollution. Green solvents have found applications in chemical synthesis and analysis. However, in this review, we have described the work done during the period 2005‒2019 on the use of green solvents like ionic liquids, surfactants, deep eutectic solvents (DES), bio-based solvents in thin-layer chromatography (TLC). To date, only one paper has been reported on the use of DES in TLC.

Eclipta alba and Guiera senegalensis have traditionally been used in Ayurvedic and Unani medicine to cure several ailments. Due to the high demand, the quantitative standardization of plant-based products is challenging to maintain their quality. We aimed to develop and validate a high-performance thin-layer chromatography (HPTLC) method for the simultaneous detection and quantification of gallic acid and quercetin in E. alba and G. senegalensis, respectively. Aqueous extracts of both plants were prepared. Qualitative and quantitative analyses were performed for the simultaneous separation of gallic acid and quercetin in each extract as per the International Conference on Harmonization (ICH) guidelines with respect to linearity, specificity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ) and robustness. HPTLC quantitative analyses for E. alba aqueous extracts revealed 3.83 µg/mg of gallic acid and 2.26 µg/mg quercetin, while 4.71 µg/mg of gallic acid and 1.06 µg/mg of quercetin for G. senegalensis. LOD was found to be 3.30 ng/band and 12.70 ng/band, while LOQ was found to be 10.20 and 38.60 ng/band for gallic acid and quercetin, respectively. The HPTLC method showed good linearity, recovery and robustness of the validated markers. This developed validated method is capable of quantifying and resolving gallic acid and quercetin and the quality control of E. alba and G. senegalensis.

This paper describes the development and application of a high-performance thin-layer chromatography method for the analysis of Kakadu plum (Terminalia ferdinandiana). The method involves a simple extraction into methanol, separation on a silica gel 60 F254 plate using toluene‒ethyl acetate‒formic acid (25:15:10, V/V) as the mobile phase. The method was applied to bulk Kakadu plum extracts and commercially available Kakadu plum powders.

There has been a recent surge in the amount of substandard and falsified clopidogrel. Pharmacopeial based assays using high performance liquid chromatography and mass spectroscopy are widely used for the measurement of clopidogrel but are not accessible in low to middle income countries. Therefore, our study explored four different techniques (mid-infrared spectroscopy, thin layer chromatography, ultraviolet visible spectroscopy, and differential pulse voltammetry), which could be used in low to middle income countries. Differential pulse voltammetry showed the best performance for accurate and precise determination of clopidogrel in the presence of excipients. Clopidogrel tablets were fully crushed and sonicated in buffer for 30 seconds prior to differential pulse voltammetry measurements using a 3 mm glassy carbon electrode. Measurements were made without removing the excipients and the limit of detection was 0.08 mg ml−1 and the sensitivity was 15.7 μA mg ml−1. When conducting a blinded study, differential pulse voltammetry was able to identify varying types of substandard and falsified samples. Our findings highlight that voltammetry could be a vital analytical technique for the determination of substandard and falsified medicines in low- and middle-income countries.

The objective of this study was to investigate the phytochemical constituents of two different parts of Vigna radiata (seeds and sprouts), and identify their anti angiogenic activity .the goal was achieved by Preliminary qualitative phytochemical screening for crude ethanolic extract of two parts of plant ; rat aorta anti-angiogenesis assay had been conducted for both extracts . isolation , separation and purification of some phytochemical constituents that belong to important groups (flavonoids) from n-butanol fraction extract of Vigna radiata plant had been done in pure form by using preparative thin layer chromatography ( PTLC ) and then subjected to different spectral analytical and physicochemical techniques to identify their chemical structure : melting point ( M. P) , thin layer chromatography ( TLC ) high performance liquid chromatography ( HPLC ) , Fourier transforms infrared spectra ( FTIR ) . and high performance thin layer chromatography ( HPTLC ).the result showed that the existence of coumarin , alkaloids, phenols, flavonoids , terpenoids, phytosterol and saponin.Vitexin and isovitexin were isolated in pure form .n-butanol fraction of sprouts showed highest percentage of blood vessels inhibition ( 88%) in comparison to n-butanol fraction of seeds which showed (56%). There IC50 were 58.8µg/ml and 56.6 µg/ml respectively. The difference of anti angiogenic activity may be related to the variation of concentration of the bioactive constituents or appearance of new bioactive constituents during germination. Keywords: Vigna radiata, vitexin, isovitexin ,high performance thin layer chromatography HPTLC , high performance liquid chromatography HPLC

In this study, thin-layer chromatography was applied for selective extraction of volatile compounds in perfume prior to analysis with solid phase microextraction and gas chromatography-mass spectrometry. The standard compounds were desorbed from the thin-layer chromatography plate and extracted at 80°C for 15 min showing good linearity of the calibration curves (R2 > 0.98) and acceptable recovery range (65-81%). The plate after the separation was cut into four smaller parts followed by solid phase microextraction/gas chromatography-mass spectrometry analysis, which revealed different compound profile in each part with the correlation between log P of the standard compounds and their positions along the thin-layer chromatography plate (R2 = 0.65). This approach was applied to analyze perfume compounds in the sample with strong matrix interference from the synthetic agarwood. Terpene hydrocarbons (woody-based odors), ketones/esters, aldehydes, ethers, and alcohols were mostly observed at 8 ± 1, 6 ± 1, 5 ± 2, 4 ± 2, and 3 ± 2 cm, respectively, from the bottom of the thin-layer chromatography plate. While, the conventional solid phase microextraction/gas chromatography-mass spectrometry analysis of this sample solution revealed only 62 compounds (including 35 perfume compounds), the four-piece approach resulted in 109 compounds (62 perfume compounds). Furthermore, the capability of thin-layer chromatography-Gas Analyzer approach to analyze the isomers in this complex sample was demonstrated.

Aflatoxin B1 (AFB1) is a natural carcinogenic contaminant of agricultural product regulated at parts per billion (ppb) level; therefore, a validated method for the analysis of AFB1 is extremely important. In this study, a high-performance thin-layer chromatography (HPTLC) method was standardized and validated with respect to linearity, sensitivity, precision, and accuracy for the quantification of AFB1. Three extraction techniques using different solvent systems, namely QuEChERS (quick, easy, cheap, effective, rugged and safe) method, Contaminants Branch method and Best Foods method were evaluated for AFB1 extraction efficiency in food commodities, wherein QuEChERS method using acetonitrile‒methanol (40:60, V/V) gave maximum recovery of AFB1 in all commodities. Maximum AFB1 was recovered in dried chilli sample (89.98%), whereas the least recovery was obtained in wheat sample (68.20%). The optimized HPTLC method with chloroform‒acetone (9:1, V/V) as the mobile phase showed a compact AFB1 band at RF value of 0.36 ± 0.02. The linear regression analysis of AFB1 showed good linearity over 10, 20, 40, 60, 80, 100, 120 ng/spot with a regression value of 0.9923 and %RSD less than 1. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.133 ng/band and 3.434 ng/band, respectively. The optimized HPTLC method was further used to assess the AFB1 content in marketed samples of groundnut, corn, rice, wheat and dried chillies from the Mumbai region and it was found that 8 groundnut samples, 5 corn samples, 5 wheat samples, and 7 chilli samples out of 20 each had AFB1 concentration above Indian permissible regulatory limit of 30 ppb.

Tris(2-chloroethyl)amine is a chemical warfare agent which is considered to be a persistent contaminant highly resistant to decontamination. The time dependence of tris(2-chloroethyl)amine degradation on the water pH value is observed to determine decontamination options using the decontamination of hydroxide-based mixtures which are used by a number of armed forces. The kinetics was observed using thin-layer chromatography and gas chromatography. The time development of tris(2-chloroethyl)amine concentration decrease in the environment with the pH ranging from 7.5 to 12.5 was recorded. The reaction rate constants were established at all observed pH values, half-lifes of reactions and the influence of temperature on the reaction rate at a slightly alkaline pH of 8.5. The equation to estimate the rate constant of the first step of tris(2-chloroethyl)amine hydrolysis at various temperatures was formed. The rate of triethanolamine formation in the samples of neutral to alkaline pH was recorded. The results indicate the substantial influence of pH on tris(2-chloroethyl)amine hydrolysis. The rate constant was significantly increased from a neutral environment to the pH of 12.5 reaching 500% of the original value using alkalisation. The hydrolysis in a neutral environment was also influenced by the analyte concentration. The concentrated solutions hydrolysed more slowly as a result of hydrochloric acid release as the acid lowered the pH value of the environment. The results demonstrate that there is an important kinetic difference between sulphur and nitrogen mustard hydrolysis in an alkaline environment.

A sensitive, simple and validated thin-layer chromatography (TLC) method (method A) and a high-performance thin-layer chromatography (HPTLC) method (method B) have been developed for the simultaneous determination of linagliptin (LNG) and empagliflozin (EMP) in laboratory prepared mixtures and in their co-formulated pharmaceutical preparations. Chromatographic separation has been done using TLC silica gel 60 F254 aluminum plates (20 cm × 10 cm, 0.25 mm thickness) and the mobile phase consisting of chloroform‒methanol‒ammonia (33%) (9:1:0.1, V/V) for method A. Chromatographic separation in method B was carried out using HPTLC nano-silica gel 60 F254 glass plates (10 cm × 10 cm, 0.1 mm thickness) and the mobile phase consisting of chloroform‒methanol‒ammonia (25%) (10:1:0.1, V/V). The optimized chromatographic conditions gave good peak shapes with good resolutions at acceptable RF values of 0.25 ± 0.01 for EMP, 0.56 ± 0.01 for LNG in method A, 0.31 ± 0.01 for EMP and 0.71 ± 0.01 for LNG in method B. Both methods were validated for linearity, accuracy, precision and specificity. The calibration plots were linear over a concentration range of 0.4‒10 µg/band with a correlation coefficient of 0.9998 for EMP and 0.2‒5.0 µg/band with a correlation coefficient of 0.9998 for LNG in method A. In method B, the linear range for calibration was 0.1‒5.0 µg/band with a correlation coefficient of 0.9999 for EMP and 0.05‒2.5 µg/band with a correlation coefficient of 0.9999 for LNG. The optimized methods were successfully applied for the determination of the studied drugs in laboratory prepared mixtures and in their co-formulated pharmaceutical preparations with no significant difference observed upon statistical comparison between the proposed and reported methods.

Convolvulus arvensis is a species of bindweed that is rhizomatous and is in the morning glory family (Convolvulaceae) native to Europe and Asia. The plant is naturally grown in Iraq. The plant was reported to be used in traditional medicine from as early as 1730s. The Aerial parts of Convolvulus arvensis were macerated in 80% ethanol for 6 days. The concentrated extract was partitioned with n-hexane, chloroform, ethyl acetate- and n-butanol successively. The n-hexane and ethyl acetate, fractions were examined for the presence of phytochemicals by thin layer chromatography and high performance liquid chromatography and its steroid and flavonoid contents were investigated. Stigmasterol was isolated from n-hexane fraction and identified by liquid chromatography/mass spectroscopy. Rutin was isolated from the ethyl acetate fraction and identified by liquid chromatography/mass spectroscopy. The aim is to examine the phytochemical constituents of the aerial parts of Convolvulus arvensis, literature survey available so far revealed that there were no studies about the phytochemical investigation for Convolvulus arvensis in Iraq. Different chromatographic techniques like Thin Layer Chromatography and mass spectroscopy were used and the presence of Stigmasterol and Rutin in aerial parts of Convolvulus arvensis was indicated.

To elucidate the interactions between crude drugs in Kampo medicines (traditional Japanese medicines), it is important to determine the content of the constituents in a cost-effective and simple manner. In this study, we quantified the constituents in crude drug extracts using thin-layer chromatography (TLC), an inexpensive and simple analytical method, to elucidate the chemical interactions between crude drugs. We focused on five crude drugs, for which quantitative high-performance liquid chromatography (HPLC) methods are stipulated in the Japanese Pharmacopoeia XVIII (JP XVIII) and compared the analytical data of HPLC and TLC, confirming that the TLC results corresponded with the HPLC data and satisfied the criteria of JP XVIII. (Z)-ligustilide, a major constituent in Japanese Angelica Root, for which a method of quantification has not been stipulated in JP XVIII, was also quantitatively analyzed using HPLC and TLC. Furthermore, Japanese Angelica Root was combined with 26 crude drugs to observe the variation in the (Z)-ligustilide content from each combination by TLC. The results revealed that combinations with Phellodendron Bark, Citrus Unshiu Peel, Scutellaria Root, Coptis Rhizome, Gardenia Fruit, and Peony Root increased the (Z)-ligustilide content. Quantifying the constituents in crude drug extracts using the inexpensive and simple TLC method can contribute to elucidating interactions between crude drugs in Kampo medicines, as proposed by the herbal-pair theory.

We investigated and compared hydrophilic retention mechanism (HILIC) of ten compounds (imidazoline and serotonin receptor ligands) in the thin-layer chromatographic (TLC) system and the high-performance liquid chromatographic (HPLC) system. The TLC and HPLC stationary phases were the chemically bonded amino (NH2) phases. In the TLC mode, the binary mobile phases were composed of acetonitrile (as the main component) and water or methanol (as the modifier). In the HPLC mode, the binary mobile phase was composed of acetonitrile (as the main component) and methanol (as the modifier). For each compound, we determined this region for which linear relationship between the retention and volume fraction of the mobile phase modifier was observed, and the retention behaviour was described by the linear solvent strength (LSS) model. With the obtained regression constant values (log k0, RM0) in mind, we selected molecular parameters influencing retention mechanism in the considered chromatographic systems. Lipophilicity plays an important role in the TLC mode with the acetonitrile‒methanol mobile phase, while geometrical characteristics of the test compounds (ring complexity, number of multiple bonds) play a predominant role in the TLC mode with the acetonitrile‒water mobile phase. It was also established that the hydrophilic mechanisms are different for the non-aqueous TLC vs. aqueous TLC systems and for the TLC vs. HPLC systems. As a result, different elution orders and separation performances can be expected for the imidazoline and serotonin receptor ligands, depending on the chromatographic system employed.

Quality control, nutritional value and the monitoring of hazardous residues in honey bee- products have become major topics for both producers and consumers. Due to its potential role in human health, bee-products rich in bioactive compounds are becoming increasingly popular. This review aims to provide an overview of thin-layer chromatography methods used in quality control, authenticity testing and chemical profiling of bee-products in order to help scientists engaged in the field of bee-products chemistry to utilize the advantages of this technique in the detection and elimination of fraudulent practices in bee-product manufacturing. Recently, hyphenation of thin-layer chromatography, image analysis and chemometrics support bee-products analysis by simultaneous determination of analytes with different detection principles, identification of individual bioactive compounds as well as structure elucidation of compounds. Highlighted opportunities of thin-layer chromatography could encourage further investigations that would lead to improvements in the detection and elimination of marketing fraudulent practices.

Dendrobium hercoglossum Rchb. f. (D. hercoglossum), as one of the origins of medicinal Dendrobium, has been widely used as a health food and nutrient source promoting fluid production. Due to a lack of quality control, it is often counterfeited or mixed with other Dendrobium. In this study, a high-performance liquid chromatography characteristic chromatogram method is established for the quality evaluation of D. hercoglossum. Based on the high-performance liquid chromatography characteristic chromatogram, D. hercoglossum is divided into two classes, each with different flavone peaks. These flavone peaks were identified using high-performance liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry. Among them, the acylated (3-hydroxy-3-methylglutaryl, p-coumaroyl, feruloyl, or sinapoyl) flavones-C-glycosides are first found in D. hercoglossum in this study. In addition, one unique band was found in D. hercoglossum by thin-layer chromatography, which can be used to distinguish it from other Dendrobium species as a characteristic marker of this plant. Combining the high-performance liquid chromatography characteristic chromatogram and high-performance liquid chromatography coupled with electrospray ionization multistage tandem mass spectrometry, the unique band was identified as 4,5-dihydroxy-3,3'-dimethoxybibenzyl. These analysis methods can be applied for the quality control and identification of D. hercoglossum as well as providing reference for the identification of similar constituents in other Dendrobium species.

211At is artificially produced for medical purposes. To prevent severe loss of short-lived 211At, a rapid method analyzing both the radioactivity and all chemical forms was required for related fundamental researches. We propose a new method by means of an α-scintillation-camera system comprising of thin-layer chromatography and a high-sensitive CCD camera. The performance of the system was experimentally verified: low-radioactivity 211At of 56–672 Bq was measured in a short-time of 1000 s and all chemical forms of 211At were evaluated. The results reveal that the method enables us to analyze two features of 211At with significantly short-time.

This review article describes the work reported on the separation and analysis of heavy metal ions by different modes of thin-layer chromatography (TLC) such as soil, micellar, and reversed-phase TLC during 2000–2019. The history of different modes of TLC has been briefly mentioned. The literature survey reveals that the number of papers reported during 2000–2019 on the separation of heavy metal ions by different modes of TLC follows the trend: micellar TLC > soil TLC > reversed-phase TLC.

Saffron, one of the most expensive spices around the world, is highly vulnerable to economic adulteration in its powder form. Plant materials and artificial colorants are commonly used as adulterants to reduce saffron concentration as well as maintaining color strength in powdered saffron products. However, current analytical methods lack the ability to test samples accurately onsite. Therefore, the objective of this study is to develop a fast screening and quantification method combining thin-layer chromatography (TLC) and Raman spectroscopy for saffron powder analysis, including quantifying the main colorant crocin content and identifying possible adulterants out of a lab setting. A droplet of aqueous extract of saffron powder was deposited on a TLC plate, exhibiting a uniform yellow round pattern on the TLC plate. The content of crocin was analyzed using the ISO 3632 method and Raman spectroscopy separately. A quantitative model based on Raman spectra was established and validated using partial least square (PLS) with R of 0.9955 and 0.9929 for calibration and validation of the PLS plot, respectively. Possible adulterants such as powders of safflower, turmeric powder, red 40 (allura red), and yellow 5 (tartrazine) were mixed with saffron powder at various degrees. Their water extracts exhibited unique patterns under bright ambient light and UV light that can be discriminated from that of pure saffron samples through visual observation and principal component analysis (PCA) based on the L*a*b* values. We also estimated the lowest adulteration degrees that can be detected were 2.59% for Allura red, 4.15% for tartrazine, 31.01% for safflower, and 41.98% turmeric, respectively, using the PLS analysis. Further identification was evaluated using Raman spectroscopy, which provided fingerprint spectra for all adulterants except safflower. Combining TCL pattern and Raman spectroscopy, samples with identical optical properties to pure saffron but adulterated with multiple adulterants were analyzed and successfully detected. This study demonstrates the potential practical application of this method in rapid analysis of saffron quality and adulteration.

Sensors, biosensors, lateral flow immunoassays, portable thin-layer chromatography and similar devices for hand-held assay are tools suitable for field or out of laboratories assays of various analytes. The assays frequently exert a limit of detection and sensitivity close to more expensive and elaborative analytical methods. In recent years, huge progress has been made in the field of optical instruments where digital cameras or light sensitive chips serve for the measurement of color density. General availability of cameras, a decrease of prices and their integration into wide spectrum phones, tablets and computers give the promise of easy application of analytical methods where such cameras will be employed. This review summarizes research on hand-held assays where small cameras like the ones integrated into smartphones are used. Discussion about such assays, their practical applicability and relevant specifications are also written here.

Background Aminexil, a new compound patented by L’Oreal, has a stimulating effect on human keratin fibers. Pyridoxine HCl and niacinamide are added to boost the hair tonic effect of aminexil. Objective Two novel chromatographic methods were developed for the determination of aminexil (AX), niacinamide (NA) and pyridoxine HCl (PD) in the novel hair tonic preparation. Methods The developed methods were high-performance liquid chromatography (HPLC) and thin layer chromatography (TLC) with densitometric determination. Different experimental parameters were investigated and optimized to achieve complete baseline separation and well resolved peaks. The RP-HPLC separation was achieved using a Thermoscientific BDS hypersil C18 (250 × 4.6 mm, 5 µm) column using 0.005 M hexane sulfonic acid: methanol (80: 20, v/v) as a mobile phase. For the TLC method, the three analytes were partitioned between propanol: toluene: ammonia solution (40:60:2, v/v/v) and fluorescent silica plates. The two methods were validated in compliance with International Conference on Harmonization (ICH) guidelines. The obtained data were statistically analyzed to confirm the existing results. The developed methods were successfully applied for determination of the studied drugs in pure forms and in the cosmetic preparation. Results For the HPLC method, the RSDs of AX, NA and PD were 0.70, 0.88 and 1.17 respectively. For the TLC method, the RSDs of AX, NA and PD were 1.06, 1.37 and 0.73 respectively. Conclusions The proposed chromatographic methods showed high sensitivity and selectivity for the three compounds under analysis in the laboratory prepared mixture and in the hair tonic preparation. Highlights Aminexil, Pyridoxine, Niacinamide, HPLC. The present work offers two reproducible, accurate, validated, time and cost saving alternatives for the quantitative and qualitative determination of medicated hair preparation.

Separation of amino acids (AAs) and their simple and inexpensive determination/identification is an interesting topic in biological and protein science, different food industries, and drug factorie...