Silica Gel TLC Plates Research Articles

Development of a highly sensitive and eco-friendly high-performance thin-layer chromatography approach for the determination of empagliflozin, pioglitazone, and rosuvastatin simultaneously in pharmaceutical preparations and different biological fluids

A simple, accurate, green and selective high-performance thin-layer chromatography (HPTLC) method has been developed and validated for the simultaneous estimation of empagliflozin, pioglitazone, and rosuvastatin in their synthetic ternary mixture and different biological fluids. These three drugs are used for the treatment of type 2 diabetes mellitus and dyslipidemia and have shown synergistic effects on cardiovascular outcomes. The ternary combination was separated on silica gel TLC plates G60 F254, utilizing a mixture of n-hexane‒ethyl acetate‒methanol‒glacial acetic acid in ratio (4.2:4:1.75:0.05, V/V) as a developing system using ultraviolet (UV) detection at 230 nm. All experimental parameters were optimized with a linearity range of 5‒250 ng per band for each drug, with good sensitivity and low limit of detection values reached, namely 1.72, 1.79, and 1.52 ng per band for empagliflozin, pioglitazone, and rosuvastatin, respectively. The developed method was applied for separation of the studied drugs in their synthetic ternary mixture and different biological fluids, with good recovery results ensuring high efficiency of the proposed approach. Eco scale, green analytical procedure index, and AGREE metric tools were used to evaluate the greenness of the proposed method.

A Simple Validated High-performance Thin-layer Chromatographic-densitometric Analysis Method for Simultaneous Quantitation of Betulin, Lupeol, Stigmasterol, and β-sitosterol in Asteracantha longifolia (L.) Nees

ABSTRACT Background: Asteracantha longifolia (L.) Nees is an essential and versatile ingredient in traditional medicine and herbal formulations, owing to their in curing ability against numerous diseases and disorders. There are forms of utilization like hot water extract, Methanol and ethanol extracts, as well as in some eastern parts of India, the plant is used daily as a leafy vegetable for human consumption during the medical treatment2,3. Also, it is considered a nutritious fodder for cattle. With many essential vitamins and minerals, available literature also reports vital phytoconstituents like Betulin, Lupeol, Stigmasterol, and β-sitosterol as therapeutic activity enhancers for Asteracantha longifolia (L.) Nees. Standardizing these vital phytoconstituents in the raw material will control the quality of the herbal formulations, extracts, and nutritional value. Aim: To develop and validate a HPTLC method-densitometric analysis method for simultaneous quantitation of four phytoconstituents of Asteracantha longifolia (L.) Nees. Objective: The method should be simple, capable of separating Betulin, Lupeol, Stigmasterol, and β-sitosterol to simultaneously estimate the contents at 366nm and 540nm. Further, the method is validated following the guidelines laid by ICH, Q2 (R1). Materials and Methods: Precoated F254 silica gel TLC plates of Merck were utilized as stationary phase to carry out the separation in combination with n-Hexane: Ethyl acetate (8:2) as mobile phase. After development phytoconstituents were derivatized with Anisaldehyde Sulphuric Acid Reagent and TLC plates are dried at 100 °C for 3 min before visualization at 366nm and 540nm. Results: In summary, the method separates all the phytoconstituents adequately and is specific, the limit of detection–limit of quantification for betulin is 0.8 ng and 2.4 ng, lupeol is 0.3 ng and 1.02 ng, and total sterols is 0.2 ng and 0.7 ng the coefficient of variance for precision (Intraday and Interday) is Not more than (NMT) 5%, Linearity and Range is 0.5ng to 6ng, and Recovery ranges from 88.5% to 96.8%. Conclusion: It is evidential from the obtained results of the study that method is selective, sensitive, and reproducible for simultaneous analysis of Betulin, Lupeol, Stigmasterol, and β-sitosterol in Asteracantha longifolia (L.) Nees.

Optimisation of Extraction and TLC-Densitometric Analysis of α- and γ-Mangostin from the Rind of Garcinia mangostana L

Mangosteen (Garcinia mangostana L.) is a plant from Southeast Asia, including Indonesia, Malaysia, Thailand, and Myanmar, commonly used in traditional medicine. This study aims to determine the best solvent for the extraction of α-mangostin and γ-mangostin and develop a validated analytical method for simultaneously determining both compounds. The dried rind of G. mangostana (500 mg) was extracted with ethanol, ethyl acetate, and acetone by percolation. The percolates were evaporated to obtain viscous crude extracts. The TLC-densitometry technique was employed to determine the content of α-mangostin and γ-mangostin in the extracts. Chromatographic identification of the contents was carried out on a silica gel TLC plate (GF254) with a mobile phase of chloroform: ethyl acetate: hexane: formic acid (5:2:3:1) using standard αmangostin and γ-mangostin as reference compounds. The method has satisfactory linearity and meets the criteria for precision and accuracy at concentrations of 100 – 500 µg/spot for αmangostin and 200 – 500 µg/spot for γ-mangostin. The results showed that ethyl acetate extract had the highest concentration of α-mangostin and γ-mangostin at 3.05±0.22% and 0.22±0.15%, respectively. The TLC-densitometry technique is suitable and practical for the simultaneous routine analysis of α-mangostin and γ-mangostin in G. mangostana rind extract. Keywords: mangosteen rind extract, mangostin, percolation, TLC-Densitometry

Inulin determination of yam bean tuber (Pacyrrhizus erosus l.) water extract from different altitude areas using TLC- Densitometry

Inulin is a polysaccharide with a lot of potential in the field of food and pharmaceuticals. Inulin can be found in yam bean tuber. Chemical constituents of yam bean tuber are inulin, pachyrion, and rotenone. The levels of inulin could be influenced by differences in the altitude of the cultivation area. The objective of this study was to determine the inulin of yam bean tuber extract from several areas in East Java based on the altitude difference, they are low (Gresik), middle (Kediri), and high (Malang), using validated TLC Densitometry method. The samples were extracted by the infusion method. The samples were put to silica gel TLC plates and developed using ascending chromatography with a mobile phase of 0.5:7:2 glacial acetic acid: methanol:  deionized water.  Densitometry at 380 nm was used to assess the intensity of inulin spots dipped in Aniline: diphenylamine: phosphoric acid (5:5:1), and winCATS software version 1.3.0 was used to quantify the results. A standard curve  meets the requirement of linearity (r=0.997; Vxo=3.847%), sensitivity (LOD=71.030 ng/spot, and LOQ=236.766 ng/spot), selectivity and specificity, Precision (RSD≤2.754 %), and accurate (% recovery ± RSD = 100.161 ± 1.839%). The results showed that the inulin content in yam tubers produced by areas with different altitudes had different inulin levels. The levels of inulin derived from the low altitude (Gresik) was 9.066 ± 1.218 %, middle (Kediri) was 7.776 ± 0.420 %, and high (Malang) was 6.796 ± 2.045 %. One-Way ANOVA test showed the significant difference between the levels of inulin from different altitude areas (p < 0.01), the highest inulin level comes from yam bean tuber from low altitude. Â

DEVELOPMENT AND VALIDATION OF ANALYTICAL METHOD FOR SIMULTANEOUS ESTIMATION OF ELLAGIC ACID AND BERBERINE IN POLYHERBAL FORMULATION BY HPTLC

A rapid, precise, robust, and selective HPTLC technique has been developed for the simultaneous estimation of ellagic acid and berberine from a marketed polyherbal formulation. Chromatographic separation was performed over pre-coated silica gel TLC plates, via a linear ascending technique using toluene, ethyl acetate, acetic acid and formic acid as the mobile phase. Detection and quantification were achieved at 286 nm by spectro-densitometric analysis. Analytical performance of the proposed HPTLC method was validated according to the ICH guidelines for linearity, accuracy, precision, detection and quantitation limits, robustness and specificity. The regression analysis data indicated a good linear relationship for the calibration plots for ellagic acid and berberine in the range of 200-800 ng spot-1 each, and regression coefficients were 0.9924 and 0.9951, respectively. The proposed method can also be used for the estimation of these phytoconstituents in other polyherbal formulations.

Ultrasensitive TLC determination of montlukast and loratadine mixture in human plasma utilizing fluorescence detection at dual pH values: Toward attaining separate maximum fluorescence intensity

A novel selective and highly sensitive TLC densitometric method with reflectance/fluorescence detection was developed to separate and quantify montlukast (MONT) and loratadine (LOR). Separation of the studied drugs was performed on precoated silica gel TLC plates using chloroform–ethyl acetate (8 :2 v/v) as a mobile phase. MONT quantification was carried out by measuring emission using 400 nm optical filter after excitation at 340 nm. Enhancement of the week LOR fluorescence was performed through adequate spraying the chromatograms with 0.2 M perchloric acid leading to enhancing sensitivity by 17 folds compared to the reported HPTLC methods with absorbance detection. The scanner was set at 275 nm excitation wavelength and 400 nm optical filter. Detection of both drugs on the same plate separately at different pH conditions was utilized for the first time. Maximum fluorescence was achieved for each of them and this enhances detection sensitivity for both drugs. The linear regression analysis data of the studied drugs produced a good linear relationship with correlation coefficients of 0.996 for MONT and 0.998 for LOR over the concentration range of 6 – 150 ng/band for MONT and 15 – 120 ng/band for LOR. Limit of detection values were 1.7 and 4.5 ng /band for MONT and LOR respectively. The developed method enabled the detection of MONT and LOR in human plasma samples within linear concentrations ranged from 7 to 140 ng/ band and 16 to 50 ng/ band with detection limits of 1.9 and 4.8 ng/band for MONT and LOR respectively.The analytical performance of the proposed method was evaluated according to the International Council for Harmonization (ICH). The method was successfully applied for the analysis of the studied drugs in spiked human plasma and good recovery percentages were obtained indicating that there is no interference from plasma constituents. Therefore the method can be applied for in vivo analysis and pharmacokinetic study.

The Effect of Gamma Irradiation on Ethanolic Extract of Temulawak (Curcuma xanthorrhiza Roxb.) Against Human Cancer Cell Lines

The Effect of Gamma Irradiation on Ethanolic Extract of Temulawak (Curcuma xanthorrhiza Roxb.) Against Human Cancer Cell Lines. One of the medicinal plants that are widely used by the people of Indonesia is temulawak (Curcuma xanthorrhiza Roxb.) with the active ingredient is curcuminoid. The curcuminoid is a yellow compound that is believed to have anti-cancer properties, therefore its properties must be maintained in the post-harvest process. This research aimed to study the effect of gamma irradiation on the simplicia of C. xanthorrhiza rhizomes in inhibiting the proliferative activity against human cancer cell lines. The dry powder of C. xanthorrhiza rhizome was irradiated with gamma at a dose of 10 kGy in 2 replications, then extracted using ethanol solvent, evaporated, to obtain an ethanol extract. As a control, an un-irradiated sample was prepared and extracted in the same manner. Each ethanol extract from irradiated and control samples was then tested for their antioxidant activity by DPPH method and antiproliferative activity against human cancer cell lines (HUT78, A549, HeLa, and THP1). The results showed that the ethanol extract of irradiated C. xanthorrhiza rhizome with a dose of 10 kGy still had antioxidant activity and anticancer properties based on the bioassay against four those human cancer cell lines, although the antiproliferative activity decreased between 8-30% compared to the control sample. The highest antiproliferative activity was shown by the ethanol extract against HUT78 cancer cell line with IC50 values of 5.4 and 10.7 µg/ml for control and irradiated samples respectively. Based on the silica gel TLC plate, the ethanolic extracts of C. xanthorrhiza rhizome both unirradiated- and irradiated samples contained curcumin (Rf = 0.58) and demethoxycurcumin (Rf = 0.38).

HPTLC-densitometry quantification of fructooligosaccharides from inulin hydrolysate

The objective of present research was to develop an easy, precise and accurate HPTLC densitometry method for quantification of fructooligosaccharides (FOSs) from inulin hydrolysate. The chromatographic separation of FOSs was performed on pre-coated silica gel (60, F254) TLC plates using a mobile phase (butanol:ethanol:water, 60:24:16), and densitometry evaluation of FOSs was performed at A500. Both kestose and nystose were successfully resolved with Rf value of 0.43 and 0.34, respectively. The accuracy, reliability and reproducibility of developed method was assessed by percent relative standard deviation of kestose and nystose for instrument precision (1.43% and 1.50%), repeatability (1.48% and 1.56%), intra-day precision (1.60% and 1.63%), inter-day precision (1.62% and 1.66%), limit of detection (4.58 ng/spot and 4.58 ng/spot), limit of quantification (13.87 ng/spot and 13.89 ng/spot) and recovery (98.81% and 98.69%). Moreover, overlapping spectra of test sample with standard confirms the specificity of developed method, which was validated as per ICH guidelines.

Chiral Recognition by DNA-Immobilized TLC Plate

DNA-immobilized silica gel TLC plate (DNA-TLC plate) by coating a mixture of double-stranded DNA and silica gel on a glass plate was stable in common organic solvents, such as alcohol, acetone, chloroform, and ethyl acetate. DNA-TLC plate showed different Rf values for the L- and D-form acidic amino acids, such as aspartic acid and glutamic acid. The chiral recognition of an acidic amino acid by the DNA-TLC was related to the interaction between the nucleic acid base, particularly guanine (G) and cytosine (C), and the amino acid. Furthermore, the DNA-TLC plate indicated the recognition of a chiral metal complex, such as the tris(1,10-phenanthroline)ruthenium(II) ([Ru(phen)3]2+) salt, which has Λ- and Δ-forms. Therefore, the double-stranded DNA-TLC plate may have the potential to be utilized as a chiral separation material for amino acids, peptides, and a metal complex with a chiral property.

Sweet spot matching: A thin-layer chromatography-based countercurrent solvent system selection strategy

TLC-based strategies were proposed in 1979 (Hostettmann et al.) and 2005 (Friesen & Pauli; GUESS method) to minimize the number of partitioning experiments required for countercurrent separation (CCS) solvent system selection. As semi-empirical approaches, both proposed that the K values defining the sweet spot of optimal CCS corresponded to a matching Rf value range from the silica gel TLC plate developed in the organic phase of a biphasic or a corresponding monophasic solvent system. Despite their simplicity, there has been an absence of theoretical support and a deficiency of reported experimental evidence. The present study explores the theory required to develop correlations between Rf and K. All theoretical models surmise that the optimal Rf value range should be centered at 0.5. In order to validate the feasibility of the concept of matching Rf and K values, 43 natural products and six solvent system families were investigated. Out of 62 correlations, 45 resulted in matched Rf and K values. Based on this study, practical guidelines for the TLC-based prediction strategy are provided. These approaches will equip CCS users with an updated understanding of how to apply the TLC-based solvent system selection strategy to accelerate a targeted selection of CCS conditions.

Simultaneous Densitometric Determination of First Line Anti-TB Drugs in Binary, Ternary, and Quaternary Mixtures

This article presents the development of a new densitometric method for the simultaneous separation and determination of isoniazid (INH), ethambutol (EMB), rifampicin (RIF), and pyrazinamide (PZA). INH, RIF, and PZA were determined by UV detection at 270 nm, and then EMB was derivatized and detected at 250 nm. The studied drugs were determined in their pure forms, available pharmaceutical preparations, binary, ternary, and quaternary synthetic mixtures. The study was performed on precoated silica gel TLC plates using acetonitrile:chloroform:2-propanol:4 N ammonia as a mobile phase (34:31:34:1 v/v/v/v). The studied drugs have been satisfactorily resolved with Rf values 0.31 ± 0.01, 0.48 ± 0.03, 0.73 ± 0.02, and 0.09 ± 0.01 for INH, RIF, PZA, and EMB, respectively. The developed method has been validated according to ICH guidelines providing good correlation coefficients (0.9991–0.9998) with a detection limit of 18.14 to 94.34 ng/band for all studied drugs. The proposed method has the potential to determine INH, RIF, and PZA simultaneously (before spraying) and EMB after spraying of the plate with cobalt sulfate without any interference. The method is new, rapid, and inexpensive compared to the official and reported methods for the assay of the quaternary mixture of the studied drugs.

Discovery of a new caerulescent Psilocybe mushroom in Germany: Psilocybe germanica sp.nov.

Sixty years ago, the ethnomycologist R. G. Wasson discovered an ancient mushroom cult in Oaxaca, Mexico. The famousmycologist R. Heim classified the psychoactive mushroom species in the genera Psilocybe and the eminent natural product chemist Albert Hofmann published the isolation, structural elucidation and synthesis of the new alkaloids psilocybin and psilocin in 1958. These indole derivatives were also found in a number of other Psilocybe species encountered in Asia and Europe and it is now known that other psychoactive species exist in the genera Pluteus, Panaeolus, Inocybe andGymnopilus. Hallucinogenic mushrooms of the main genus Psilocybe are known from countries with a wet climate. Besides the cultivation of subtropical species such as Psilocybe cubensis (Earle) Singer, a range of other naturally growing species are commonly found in Europe. They deserve increasing attention because some species can yield up to thousands of fruiting bodies in relatively small spaces. The species Psilocybe semilanceata (Fr.) Kummer contains comparatively high amounts of psilocybin (around 1% dry weight) and some baeocystin, which is the monomethyl analogue of psilocybin, whereas the phenolic compound psilocin is only found in traces in these mushrooms (Figure 1). This small species usually grows in only scattered patterns on pasture. In recent decades, however, the psychoactive mycoflora of Europe has been transformed deeply. In 1946, E. Wakelfield described a new species from Kew Gardens (London, UK) that became known as Psilocybe cyanescens Wakefield. This mushroom typically exhibits strong blueing behaviour after bruising and also spontaneously during ageing. This species grows on wood chips and rich compost derived from plant residues. It has been suggested that these mushrooms grew adventitiously in botanical gardens following importation of plant material from foreign countries. In 1962, this species was also found in the Pacific Northwest, USA and Kubicka first discovered other blueing mushrooms in woods near Sazava (Czech Republic) in 1942. The species was named Psilocybe bohemica Sebek and further descriptions are available in the Czechmycological literature. Krieglsteiner shed new light a variety of mycological collections obtained from wood debris about 30 years ago It is now clear, however, that Psilocybe cyanescens was not in this collection. One of the present authors (J. G.) has studied these mushrooms since 1986 and found genuine Psilocybe bohemica in the Czechoslovakia in 1986 and later in 1989. It appears that the distribution of Psilocybe cyanescens has been expanding in Germany, and possibly other European countries, during the last 30 years. The reason for

A unique dansyl-based chromogenic chemosensor for rapid and ultrasensitive hydrazine detection.

We developed a new dansyl phthalimide-based fluorescent chemosensor for hydrazine detection. Upon a Gabriel type-based hydrazinolysis of dansyl phthalimide (DPI) in the presence of hydrazine in a mixture of HEPES buffer (pH 7.0, 20 mM) and DMSO (1/9, v/v) at room temperature, the chemosensor produces fluorescent dansyl-NH2 with the maximum emission wavelength changed from 475 nm to 512 nm along with a color change from yellow to colorless, allowing colorimetric detection of hydrazine by the naked eye. DPI can selectively detect hydrazine over other environmentally abundant ions. Moreover, DPI coated with silica gel TLC plates could act as a visual and fluorimetric probe for hydrazine vapor at a partial pressure of 5.5 × 10-3 mm Hg over other potentially interfering volatile analytes, including hydrogen peroxide, ethylenediamine, urea, ammonium hydroxide and methylamine. DPI can also be used for the detection of hydrazine in water samples and HeLa cells without appreciable interference from other biologically abundant analytes. The limit of detection is 6.01 ppb (1.88 × 10-7 M), which is well below the accepted limit (10 ppb) for hydrazine set by the U.S. Environmental Protection Agency (EPA).

Amine Sensing with Distyrylbenzenes and Their Hexamethylene-Linked Polymers: Spraying Them On

We herein describe synthesis and property evaluation of two aldehyde-appended nonconjugated distyrylbenzene polymers as amine sensing platforms and compare their performance to that of their monomers. The monomers and polymers were dissolved in organic solvents and spray-deposited onto silica gel and neutral alox TLC plates so as to give small strip-shaped sensor arrays. With these, differential amine detection was achieved; we find that a neutral silica gel support is better able to discern the amines than alox TLC plates.

TLC 상 유도체화 반응을 이용한 아민 계 화합물의 Screening 방법

Abstract: Methamphetamine is an amine-containing illegal drug and is distributed unlawfully in South Korea.Finding a rapid, convenient and semi-quantitative determination method for methamphetamine is a very importantissue in the area of forensic drug testing. As an effort to develop new screening method, the reactions betweenthree organic compounds which are structurally similar to methamphetamine and N-(9-fluorenylmethoxycarbonyloxy)succinimide (FMOC-NHS) were performed on silica gel (SiO 2 ) TLC plates. Three reference compounds weresynthesized and used for the identification, comparison and study of the limit of detection (LOD) of the productsobtained from a direct reaction on a TLC plate. As a result, FMOC-NHS as a derivatization reagent generatedcompounds containing highly UV-active functional groups on the TLC plate after reacting with primary- andsecondary amines. In the experiment 2D the LOD of amines was in the range of 0.045 and 0.01 mg/mL (2 µL/spot), and in 1D the LOD was in the range of 0.002 and 0.007 mg/mL (2 µL/spot). The LODs of the compoundstested were dependent on the concentration of the derivatizing reagent. 요약: 국내에서 불법 유통 되거나 남용되고 있는 methamphetamine은 아민을 함유한 불법약물로서 그에 대한 신속하고 용이한 동정 및 정량적인 분석 방법은 불법약물 검사의 중요한 이슈가 되어왔다. 새로운 screening방법을 모색하기 위해 methamphetamine과 구조적으로 유사한 3종의 유기 화합물을 silica gel(SiO

The Sequences of the Eleven‐Residue Peptaibiotics: Suzukacillins‐B

The filamentous fungus designated 'Trichoderma viride' strain 63 C-1 simultaneously produces suzukacillins (SZs), two microheterogeneous groups of peptaibols, under submerged culture conditions. Both groups are readily distinguishable by TLC: the major group is designated SZ-A, whereas the minor group with a higher Rf value is named SZ-B. The peptide mixture was obtained from a MeOH extract of the mycelium. SZ-B was separated from SZ-A by Sephadex LH-20 column chromatography. Although it provided one single spot on silica-gel TLC plates, 15 individual peptides could be separated by C8 reversed-phase (RP) HPLC, and their sequences were determined by HPLC/QqTOF-ESI-HRMS. Fourteen peptides exhibit the C-terminal sequence Pro(6) -Lxx-Lxx-Aib-Pro-Vxxol/Lxxol(11) , which is common for eleven-residue peptaibols. The remaining peptide is tentatively assigned as a ten-residue sequence, in which the C-terminal 1,2-amino alcohol is deleted, thus terminating in free proline. Nine of the peptides carry an Ac-Aib residue at the N-terminus, very frequently found in eleven-residue peptaibols. Four peptides comprise the rare Ac-Ala N-terminus, and for two peptides, N-terminal Ac-D-Iva residues were identified. One peptide contains a C-terminal residue of yet undetermined structure. Comparison with previously reported eleven-residue peptaibol sequences reveals that eight of the peptides represent new sequence analogs.

Bioassay-Guided Isolation and Identification of Antifungal Compounds from Polyalthia longifolia Benth. & Hook

Antifungal activity of the petroleum ether extract of Polyalthia longifolia leaves was detected by direct bioautography on silica gel TLC plates against Alternaria solani. The active principle was further isolated by bioassay-directed fractionation using column chromatography and followed by GC-MS analysis. Separation of active antifungal principle was done by silica gel column chromatography which produced total ten fractions. Antifungal activity of these fractions was once again checked against Alternaria solani and fraction 1, 2 & 3 were found to be most active. These three active column fractions were further analyzed by gas chromatography-mass spectrometry. The first fraction contain four major compounds are caryophyllene, aromadendrene, viridiflorene and longifolene-(V4) whereas fraction two showed presence of two major compounds are α-guaiene, β-chamigrene.

Naphthalimide trifluoroacetyl acetonate: a hydrazine-selective chemodosimetric sensor

The trifluoroacetyl acetonate naphthalimide derivative 1 has been synthesized in good yield. In acetonitrile solution, compound 1 reacts selectively with hydrazine (NH2NH2) to give a five-membered ring. This leads to OFF–ON fluorescence with a maximum intensity at 501 nm as well as easily discernible color changes. Based on a readily discernible and reproducible 3.9% change in overall fluorescence intensity, the limit of detection for 1 is 3.2 ppb (0.1 μM), which is below the accepted limit for hydrazine set by the U.S. Environmental Protection Agency (EPA). Compound 1 is selective for hydrazine over other amines, including NH4OH, NH2OH, ethylenediamine, methylamine, n-butylamine, piperazine, dimethylamine, triethylamine, pyridine, and is not perturbed by environmentally abundant metal ions. When supported on glass-backed silica gel TLC plates, compound 1 acts as a fluorimetric and colorimetric probe for hydrazine vapor at a partial pressure of 9.0 mm Hg, with selectivity over other potentially interfering volatile analytes, including ammonia, methylamine, n-butylamine, formaldehyde, acetaldehyde, H2O2, HCl, and CO2 being observed. Probe 1 can also be used for the detection of hydrazine in HeLa cells and does so without appreciable interference from other biologically abundant amines and metal ions.

Rapid and Inexpensive Densitometric Method, Using TLC Plates, for Quantification and Determination of Nine Pesticides in Water

Nine pesticides of commonly used in Gaza Strip were tested in this work for optimal separation onto silica gel TLC plates in acetone/ cyclohexane, 1:2 (v/v), as a mobile phase to develop a new densitometric method for quantification and determination of these pesticides in water samples. These pesticides are: abamectine, atrazine, benomyl, cymoxanil, diuron, imidacloprid, linuron, penconazole, and propazine. Calibration plots were linear between 25 to 1000 ng/ spot for all pesticides with a correlation coefficient, r, between 0.9920 and 0.9993. Recoveries after enrichment of real water samples on Bakerbond RP-C18 cartridges were between 79.4 and 103.7 % at a relative standard deviation between ±1.92 and 3.68 %. Detection limits LOD of 25 - 100 ng per spot for eight of the pesticides were reached, which meet the European limits for pesticides in drinking water (100 ngL-1), while penconazole has an LOD value of 200 ngL-1 because of its low UV-absorption coefficient.

Antimicrobial evaluation of hydroalcoholic extract and Volatile components of aerial part of Kelussia odoratissima Mozaff.

Kelussia odoratissima Mozaff. is a sweet-smelling, wild plant which is traditionally consumed in Iran as a garnish. Only Little, is known about its potential antioxidant activity. In this study.The antibacterial activities. against Staphylococus aureus, Escherichia coli, Bacillus cereus and Pseudomonas aeruginosa were investigated by paper Disc and immersion bioautography Methods. Separately Ethanolic extract was taken by maceration method and Volatile components was taken by cold solvent extraction method using petroleum ether. Inhibitory zones of blank discs, impregnated with defined amounts of extract were observed. and MIC were measured using E-Test. method. In bioautographic Method, extract and volatile components were separated on silica gel TLC plates to the best resolution then were placed on agar plate inoculated with bacterial suspension. After incubation for 16–18 hr at 37°C, visualization of inhibition zones was done by spraying the surface of culture media with MTT solution. Clear zone in dark purple background was the positive answer. Another TLC sheet developed with the same solvent, in the same condition was sprayed with known spraying reagents commonly used for detecting known phytochemical groups. Hydroalcoholic extract of Kelussia odoratissima were effective against E. coli, B. cereus, P. aeruginosa and S. aureus with MIC (0.64, 0.25, 0.43, 0.43mg/disc) and volatile components on S. aureus. B. cereus with MIC (0.43, 0.18mg/disc).