Partition Thin-layer Chromatography Research Articles

Influence of Chromatographic Conditions on LOD and LOQ of Fluoxetine and Sertraline Analyzed by TLC-Densitometric Method

This research introduces the analysis of fluoxetine and sertraline by means of the TLC-densitometric method. They provide information on LOD and LOQ under various chromatographic conditions. The study used adsorption (NPTLC) and partition (RPTLC) thin-layer chromatography in combination with a densitometric analysis. Four types of chromatographic plates precoated with: silica gel 60 F254, silica gel 60, silanized silica gel 60 F254 (RP-2), and a mixture of silica gel 60 and kieselguhr F254, as well as three mobile phases: chloroform + methanol + ammonia (9:1:0.4, v/v/v), chloroform + methanol + glacial acetic acid (5:4:1, v/v/v), and acetone + toluene + ammonia (10:9:1, v/v/v), were used in NPTLC. RP-18F254 and silanized silica gel 60 F254 (RP-2) plates and four mobile phases: methanol + water (10:0 and 9:1, v/v), acetone + water (10:0 and 9:1, v/v), were used in RPTLC. The lowest LOD and LOQ values for fluoxetine were obtained using a silanized silica gel 60 F254 (RP-2) with acetone + toluene + ammonia (10:9:1, v/v/v) in NPTLC, and with a silanized silica gel 60 F254 (RP-2) in combination with methanol + water (10:0, v/v) in RPTLC. The lowest LOD and LOQ values of sertraline were obtained using a silica gel 60 with acetone + toluene + ammonia (10:9:1; v/v/v) in NPTLC. The smallest amount of sertraline was detected on the silanized silica gel 60 F254 plate in combination with methanol + water (9:1, v/v) in RPTLC. The obtained results provide important information that can give a good basis and set the direction for further, more detailed research; the results can also benefit other researchers who analyze fluoxetine and sertraline with the TLC technique in model systems (testing standards) as well as in drug and biological samples.

Development of new procedures for the detection and separation of salicylic acid and acetylsalicylic acid using thin-layer chromatography with densitometry

Salicylic acid and its derivatives, such as acetylsalicylic acid, are commonly used non-steroidal anti-inflammatory agents. In the present work, different sorbents as the stationary phases and also various manners of detection using well known and new visualizing reagents have been tested for the separation and detection of the two compounds by adsorption and also partition thin-layer chromatography (TLC) with densitometry. Densitometric and spectrodensitometric analysis was used to evaluate the detectability of the examined compounds using the newly developed TLC procedures. Of all the applied manners of detection, the most universal to distinguish acetylsalicylic acid from salicylic acid in normal- as well as in reversed-phase TLC system is the use of methanolic solution of FeCl3 and CoCl2. The densitograms obtained under these conditions show symmetric and also by adsorption well separated TLC peaks of both compounds. The shape of all absorption bands of acetylsalicylic acid (ASA) and 2-hydroxybenzoic ...

The use of similarity analysis for evaluation of the chromatographic separation of salicylic acid and its selected derivatives studied by adsorption and partition thin-layer chromatography techniques

The aim of the work was the chromatographic separation of salicylic acid and their derivatives, i.e., acetylsalicylic acid, salicylanilide, salicylaldehyde, salicylamide, methyl salicylate, phenyl salicylate, 2,5-dihydroxybenzoic acid, salicylhydroxamic acid, 3,5-dinitrosalicylic acid, 3-aminosalicylic acid, 4-aminosalicylic acid, and 5-aminosalicylic acid by use of adsorption thin-layer chromatography (normal-phase thin-layer chromatography [NPTLC]) and partition thin-layer chromatography (reversed-phase thin-layer chromatography/high-performance thin-layer chromatography [RP-TLC/HPTLC]). Three qualitatively and quantitatively different mobile phases were used for the separation of salicylic acid and its derivatives. Cluster analysis (single linkage method, Euclidean distance) allowed the evaluation of the suitability of the chromatographic conditions used to separate the pairs of tested compounds. The cluster analysis data indicate that the composition of the mobile phase is fundamental in the process o...

COMPARISON OF THE DETECTION AND QUANTITATIVE LIMITS OF HYDROCORTISONE ACETATE IN DIFFERENT CHROMATOGRAPHIC CONDITIONS IN TLC

The detection (LOD), and quantification limits (LOQ) of hydrocortisone acetate in different conditions in TLC have been compared. Analysis has been performed using adsorption thin layer chromatography (NP-TLC) on chromatographic plates precoated with aluminum oxide 60 F254, aluminum oxide 150 F254, silica gel 60, silica gel 60 F254, a mixture of silica gel, and kieselguhr 60 F254 using chloroform + acetone + ammonia (25%) (8:2:0.1, v/v/v), and toluene + ethyl acetate (15:35, v/v) as well as reversed phase thin layer chromatography (RP-TLC) on the plates precoated with silica gel RP18 F254, silica gel RP8 F254 using the mixture of methanol + water in volume compositions 6:4 and 7:3. It has been proved that the stationary and mobile phase have a significant influence on the values of the detection limit (LOD), and quantification (LOQ) of hydrocortisone acetate in adsorption and partition thin layer chromatography. Using NP-TLC technique, the least amount of hydrocortisone acetate was detected and determined on plates precoated with aluminum oxide 150 F254, and silica gel 60 using chloroform + acetone + ammonia (25%) in volume compositions 8:2:0.1 as a mobile phase. By means of RP-TLC technique, the least amount of hydrocortisone acetate was detected and determined on plates precoated with silica gel RP8 F254. The detection limit (LOD) of hydrocortisone acetate determined by both TLC methods in nanogram range (51 ÷ 137 ng · spot−1) indicates that thin layer chromatography combined with densitometry may be an alternative method to the modern chromatographic techniques for hydrocortisone acetate detection.

Effect of the composition of two-component mobile phases on the separation of selected porphyrins by partition thin-layer chromatography

The effects of two-component mobile phase (CCl 4 -MeOH, CHCl 3 -MeOH, CH 2 Cl 2 -MeOH, and C 6 H 5 Cl-MeOH) on the separation of porphyrins by thin-layer chromatography is described. The results were characterized by determination of R F and Δ R F .

Effect of the structure of selected metalloporphyrins on their chromatographic properties

We have determined the effect of the structure of selected metalloporphyrins on their chromatographic properties. Separations of tetraphenylporphyrin and its Cu(II) and Ni(II) derivatives were compared in adsorption and partition thin-layer chromatography. We determined the molecular structure of tetraphenylporphyrin complexes by magnetic studies and compared the structures obtained with the aid of molecular modeling.

High-resolution anion-exchange and partition thin-layer chromatography for complex mixtures of 32P-postlabeled DNA adducts

32P-Postlabeling has emerged as a major tool for detecting DNA adducts resulting from exposure to complex carcinogen mixtures. An integral component of this assay is multi-directional PEI-cellulose TLC in which lipophilic 32P-adducts are resolved in high-salt, high-urea solvents following removal of the bulk of non-adduct radioactivity. This TLC system is very effective for adducts formed following exposure to individual carcinogens; however, adducts resulting from exposure to complex mixtures (e.g. cigarette smoke) generally appear in the form of the so-called diagonal radioactive zones. By using mixtures of polycyclic aromatic hydrocarbon- and aromatic amine-DNA adducts as well as adducts in mouse skin treated with cigarette smoke condensate, we have demonstrated that a combination of 0.3–0.4 M NH 4 OH and isopropanol-4 M NH 4OH (1-1.4:1) solvents can provide more sharply defined adduct spots than the commonly used urea solvents. The non-urea solvents also result in excellent resolution of many adducts which otherwise may remain buried in diagonal radioactive zones when using the urea solvents. In addition, the signal-to-noise ratio is increased 2- to 5-fold over the urea solvents enabling detection of discrete adducts at ≤3 adducts per 10 10 nucleotides. These partition TLC solvents also involve fewer manipulations (e.g. no water washes to remove salt and urea), and are likely to be more informative with regards to the type of individual adducts detected in the biomonitoring of humans than has hitherto been possible.

Separation Studies of Metal Ions in Sodium Thioglycolate Medium by Thin Layer Partition Chromatography

Abstract A thin layer partition chromatographic method has been developed for separation of Fe(III), Ni(II), Zn(II), Cu(II), Pb(II) and Mn(II) on thin layers of silica gel-G as an adsorbent. The Rf values were determined using 0.01–0.2 aqueous solution of sodium thioglycolate as a mobile phase. The dependence of Rf values on the migration time, pH and concentration of mobile phase has been studied. The optimum conditions for possible 3-component separation have been determined. Metal ions have been separated, detected, eluted and quantitatively determined by atomic absorption spectroscopy. The present method was applied to the separation and determination of zinc in forensic samples.

Qualitative Separation of Metal Ions by Thin Layer Partition Chromatography in Aqueous Glycolic Acid Media

Qualitative Separation of Metal Ions by Thin Layer Partition Chromatography in Aqueous Glycolic Acid Media

Use of QSAR in design of antiinflammatory fluorinated arylalkanoic acids

A series of 3-fluro-4-alkoxyphenylalkanoic acids III was synthetized and their antiinflammatory activity and fibrinolytic capacity was evaluated. The suitable fluorinated derivative with better pharmacological profile than 3-chloro-4-benzyloxyphenylacetic acid (benzofenac) was selected. Experimental, biological activities of acids III were compared with those calculated by introducing the physico-chemical parameters into the formerly derived regression equations. Good coincidence was found out, as well as similarity of the regression derived for the original series of acids extended by the acids III. Lipophilicity of the acids under study was evaluated by partition thin-layer chromatography; the values of log P of benzyloxy derivatives IIIc-IIIf were lower than tabulated values - probably due to the intramolecular hydrophobic interactions of aromatic nuclei.

Separation of Metal Ions in Tube Well Water Samples by Thin Layer Partition Chromatography

Abstract A TLC method has been developed for the separation of Fe(III), Zn(II), Cu(II), Pb(II), Mn(II) and Ni(II). Thin layers of silica gel G were used as an adsorbent. R f values were determined using 0.01–0.2 M aqueous sodium acetate as mobile phase. The dependence of the R f values on the pH, the width of the plates and the time required for migration of the ions was studied. Optimum conditions for possible 3- and 4-component separations have been determined. Ni(II), Zn(II), Fe(III), Cu(II), Mn(II) and Pb(II) having minimum concentration of 0.65, 0.5, 4.0, 0.70, 0.5 and 2.0 μg/ml, respectively have been separated. The present method was applied to the separation and detection of metal ions in tube well water samples from different villages of Orissa (India).

Separation efficiency of adsorption and partition thin-layer chromatography and reversed-phase high-performance thin-layer chromatography with chemically bonded phases for alkylphenoxyalkanoic acids

The separation of 32 alkyl-substituted phenoxyalkanoic acids from phenoxyacetic to 3-pentadecylphenoxylauric acid was studied using adsorption chromatography, three types of partition chromatography (water, formamide or liquid paraffin as stationary phases) and reversed-phase high-performance thin-layer chromatography (RP-HPTLC) with chemically bonded phases. All these chromatographic systems were found suitable from the analytical point of view, but some differences in their suitability for the separation of lower or higher homologues or in their detection sensitivity were observed. The most efficient methods seem to be RP-HPTLC and TLC on silica gel layers impregnated with formamide or dimethylformamide, respectively, the former owing to the good separation of the highest lipophilic homologues and to the formation of discrete spots, permitting sharper analytical differentiation of acids with smaller Rf F differences in general, and the latter owing to the highest ΔR M values for the methylene groups of all the homologues in connection with high detection sensitivity. The best detection was achieved by using 2,7-dichlorofluorescein as the spray reagent followed by observation in UV light. The detection limit was 0.5-10 μg of the acids, depending on the chromatographic system used.

On the quantitative relations between structure and antiaggregation activity of ω-aryl-ω-oxoalkanoic acids

A series of ω-aryl-ω-oxoalkanoic acids, I-IV, has been prepared and investigated for dissociation constants in 80% methylcellosolve, retention characteristics in thin-layer partition chromatography and partition coefficients P in the system octanol-water. Also evaluated were their anti-inflammatory efficacy and inhibitory effect on the platelet aggregation induced by collagen. Analysing the relations between structure and antiaggregation effect, we obtained a non-linear, quadratic dependence of this effect on lipophilicity, the optimum being at log P = 3. The antiaggregation effect increased with shortening the chain between the carbonyl and the carboxyl, and with increasing acidity. It was also diminished by the presence of a methyl group on the interlinking chain. To assess the role of lipophilicity we used the RM values of partition chromatography. The relation between anti-inflammatory efficacy and structure was assessed only qualitatively. In this aspect, too, the nature of the chain between the carbonyl and carboxyl proved to have a marked influence. The anti-inflammatory activity proved considerably enhanced by the presence of another aromatic ring in ω-oxoalkanoic acids derived from biphenyl.

Partition thin-layer chromatography of some phenylurea herbicides

Partition thin-layer chromatography of some phenylurea herbicides

Application of Thin-Layer Chromatography to High-Performance Liquid Chromatographic Separation of Steroidal Hormones and Cephalosporin Antibiotics

Abstract High-performance liquid chromatographic (HPLC) separation of steroidal hormones and cephalosporin antibiotics was investigated by adsorption chromatography and reversed-phase chromatography, respectively. Prior to the HPLC separation of these pharmaceuticals, silica gel thin-layer adsorption chromatography of steroidal hormones and reversed-phase thin-layer partition chromatography of cephalosporin antibiotics with chemically bonded dimethylsilyl silica gel were performed in order to obtain suitable HPLC separation systems. In the separation of steroidal hormones, the same binary mobile phase ratios of TLC did not give satisfactory results in HPLC. For the sharp separation in HPLC, solvent strength in the binary solvent mixture used for TLC had to be decreased. The difference in solvent strength for efficient separation between TLC and HPLC might be attributed to the fact that in HPLC the solvent elution power acts in an isocratic manner while in TLC it acts in a gradient manner. On the other hand, a correlation of mobility between TLC and HPLC separation for cephalosporin antibiotics was obtained, and the possibility of direct transfer of chromatographic systems from TLC to HPLC for separation of these antibiotics was confirmed.

Separation of individual sulfated bile acid conjugates as calcium complexes using reversed-phase partition thin-layer chromatography.

A method for separating individual monosulfated primary bile acid conjugates by reversed-phase partition thin-layer chromatography on octadecyl-bonded silica gel is described. The solvent system is acetonitrile containing calcium, probably as calcium carbamate. Excellent resolution of the 3- and 7-monosulfated glycine conjugates, as well as 3- and 7-monosulfated taurine conjugates of cholic and chenodeoxycholic acids is reported. A convenient class separation of sulfated from nonsulfated primary bile acid conjugates by adsorption thin-layer chromatography on low-polarity silica gel is also described.

Qualitative analysis of carboxylic acids by partition thin-layer chromatography

Qualitative analysis of carboxylic acids by partition thin-layer chromatography

Trace Constituents in Whey. Isolation and Identification of Amines

Primary and secondary amines were isolated from whey as their 2,4-dinitrophenyl derivatives, separated by thin-layer partition chromatography, and identified by gas chromatography-mass spectrometry. Examination of raw and pasteurized sweet whey, reconstituted spray dried whey powder, and protein-free ultrafiltration permeate of sweet and acid wheys revealed the same qualitative distribution of amines. Amines identified were methyl-, ethyl-, isobutyl-, dimethyl-, isopropyl-, and n-amylamine, pyrrolidine, and piperidine.

New, Improved Thin Layer Chromatography for Poly chlorinated Biphenyls, Toxaphene, and Chlordane Components

Abstract Reverse phase partition thin layer chromatography is described for the separation of the different components in polychlorinated biphenyl compounds, chlordane, and toxaphene. Plates prepared from washed aluminum oxide, with silver nitrate incorporated into the layer, are saturated with a nonpolar solvent (immobile phase), air-dried overnight, and spotted. A mixture of polar solvents is used as the mobile phase. After exposure to longwave ultraviolet light, dark blue silver chloride spots form on a white background. As little as 1 μg Aroclor can be detected by this method, which can be applied for qualitative and semiquantitative measurements. Distinct patterns are obtained for Aroclor reference materials which are resolved from most DDT analogs and other commonly occurring chlorinated pesticides. Since the use of infrared, ultraviolet, nuclear magnetic resonance, and mass spectroscopy as supplementary methods for qualitative analysis involves a large capital outlay which is often beyond the resources of small laboratories, the technique is most valuable to the chemist in such laboratories where time and money are important factors.

Detection of Polychlorinated Terphenyls in Food Wrappers by Reversed-phase Partition Thin-Layer Chromatography

In order to analyse polychlorinated terphenyls (PCTs) in food wrappers rapidly, separation of PCTs from polychlorinated biphenyls (PCBs) by reverse-phase partition thin-layer chromatography (RPP-TLC) was investigated, and the method was applied to the detection of PCTs in food wrappers. The components of PCTs and PCBs were resolved on liguid paraffin layers by development with acetonitrile-acetone solvent systems, and the materials examined showed characteristic patterns composed of slightly overlapping spots. Respective perchlorinated compounds of PCTs and PCBs, o-, m-, and p-tetradecachloroterphenyls (TDCTs) and decachlorobiphenyl were also distinctly separated as well-defined spots on the thin layers, and PCTs were identified in low levels in the presence of PCBs. PCTs in food wrappers were extracted with hexane and cleaned up by Florisil column chromatography. By submitting PCT fraction directly to RPP-TLC, their presence was assumed from the pattern obtained. After perchlorination of the fraction with antimony pentachloride and extraction with benzene, PCTs were comfirmed as TDCTs in high sensitivity by RPP-TLC.