Determination Of P-aminobenzoic Acid Research Articles

Spectrophotometric Determination of p-aminobenzoic acid via Diazotization and Coupling reaction

A simple and accurate spectrophotometric method to assay p-aminobenzoic acid (PABA) has been suggested. The method based on the diazotization of PABA via reaction with nitrite ions which liberated in the medium through the reaction of sodium nitrite with hydrochloric acid, then coupling the dizotised-PABA(D-PABA)with 1-naphthylamine -7-sulphonic acid (1-NASA) to form an intense colored pink azo dye ,it is water-soluble , very stable and has a maximum absorbance at 525 nm. The absorbance was increase with the increasing of PABA amounts in the solution, and the linearity from 2.5 to70 µg in 10 ml (0.25to7 µg.ml-1).The molar absorptivity and Sandell ҆s sensitivity values have been calculated they equal to 3.6057x104 L.mol-1 cm -1 and 0.0037993 µg. cm-2 respectively. The two values above demonstrated a good sensitivity of the suggested method. The method has been used in estimated PABA resulted from analysis of folic acid in tablet.

Preparation of yolk–shell structured Ag@Cu particles and their application in high performance electrochemical sensing of p-aminobenzoic acid

In this work, the Ag@Cu particles with yolk–shell nanostructure was prepared by facile solvothermal method, which was modified on glassy carbon electrode (GCE) to fabricate electrochemical sensor for the convenient and fast determination of p-aminobenzoic acid (PABA). The surface morphology and electrochemical properties of the as-prepared Ag@Cu nanocomposite modified electrode were characterized by scanning electron microscopy, transmission electron microscopy, chronocoulometry, and electrochemical impedance spectroscopy. Further, the electrochemical sensing of PABA was performed on the Ag@Cu/GCE using cyclic voltammetry and differential pulse voltammetry techniques, showing high catalytic activity. Under the optimal conditions, the sensor exhibited a wide linear range, high sensitivity, and low detection limit of 0.315 μmol/L for PABA. The developed sensor was also successfully applied for PABA detection in anesthetic and cosmetics with satisfactory results.

High-performance liquid chromatography utilization of ionic liquids as mobile phase additives for separation and determination of the isomers of amino benzoic acids

Abstract For the isomers of amino benzoic acid, including o-, m-, p-amino benzoic acid, the beneficial effects of using the ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]), as mobile phase additives on retention behavior and separation were investigated. Chromatographic separation of the o-, m-, p-amino benzoic acid was performed on a reversed-phase C18 column by ultraviolet detection at 245 nm. The effects of several chromatographic parameters, concentrations and pH values of [BMIm][BF4] solutions, methanol concentration and length of alkyl chain on different ionic liquids, on the separation and determination of the isomers were evaluated. The optimized chromatographic conditions were established using an aqueous 0.5 mmol/L [BMIm][BF4] solution (pH 3.0)/methanol (40:60, v/v) as mobile phase without need of gradient elution, with separation of three amino benzoic acids achieved within four min. The calibration curve showed good linearity over the tested range of 2 mg/L to 120 mg/L for the three isomers with a correlation coefficients of 0.9999. The recoveries of the three amino benzoic acids of spiked components were between 99.8% and 100%. The method has been successfully applied to the determination of p-amino benzoic acid in the pharmaceutical, Bromine Mitag Procaine Injection.

An innovative nano‐sorbent for selective solid‐phase extraction and spectrophotometric determination of p‐amino benzoic acid in cosmetic products

A novel nano-sorbent was developed for selective extraction and pre-concentration of p-amino benzoic acid (PABA) prior to determination by spectrophotometry. Selective extraction of PABA from aqueous solutions was performed using a solid-phase extraction column packed with 200 mg of nickel-zinc-aluminium layered double hydroxide (Ni-Zn-Al LDH) as a nano-sorbent. Extraction procedure is based on the adsorption of p-amino benzoate ions on the Ni-Zn-Al-nitrate LDH and/or their exchanging with LDH interlayer nitrate ions. After elution of extracted analyte by 2.5 mL of 2 mol L(-1) NaCl solution, its concentration was determined spectrophotometrically at λmax = 268 nm. The spectrophotometry method gave a linear response for PABA within the range of 12.5-425.0 μg L(-1) with a correlation coefficient of 0.9994. In the optimum experimental conditions, the limit of detection and sorption capacity were 3.78 μg L(-1) and 21.25 mg g(-1) , respectively. The presented method uses mild separation conditions and is a sensitive, reproducible, simple, low-cost and environment-friendly technique that could be used for the extraction and determination of PABA in various cosmetic samples.

Spectrophotometric determination ofp-aminobenzoic andp-aminosalicylic acid derivatives in drugs and biological media

Spectrophotometric determination ofp-aminobenzoic andp-aminosalicylic acid derivatives in drugs and biological media

Determination of p-aminobenzoic acid in the presence of bovine serum albumin by room-temperature phosphorimetry on a poly(vinyl alcohol) substrate

Solid substrate room-temperature phosphorimetry on a poly(vinyl alcohol) (PVA) substrate was applied to the analysis of p-aminobenzoic acid (PABA) in the presence of bovine serum albumin (BSA). The buffer solution containing PABA and BSA was spotted on the PVA substrate and after sufficient drying, room-temperature phosphorescence (RTP) measurements were performed on both the front and the back side of the substrate. The BSA was separated on the front surface of the substrate and it emitted a negligibly weak RTP signal. Therefore, the RTP measurement of PABA on the reverse of the sample spotted side was not interfered by BSA, whereas, impurities in the BSA permeated into the PVA and emitted a weak RTP signal on the back side of the substrate. However, the RTP intensities of the impurities were weak enough as compared to that of PABA under the experimental conditions, so that their interference could be neglected. To improve the RTP intensity and reproducibility of PABA in the presence of BSA, a new substrate that consisted of Millipore-VS and PVA layer was prepared. The analytical figures of merit of this substrate obtained under the best experimental condition for maximum phosphorescence emission are a relative standard deviation of 6.0% ( n=5) at a level of 2 nmol/spot and a linear calibration curve from 0.5 to 20 nmol/spot with a correlation coefficient of 0.996 for 25 data points.

Determination of p-aminobenzoic acid and its metabolites in rabbit plasma by high-performance liquid chromatography with fluorescence detection

A simple, accurate and sensitive high-performance liquid chromatographic method with fluorescence detection was used for measuring plasma concentrations of p-aminobenzoic acid (PABA) and its three metabolites: p-acetaminobenzoic acid (PAABA), p-aminohippuric acid (PAHA) and p-acetaminohippuric acid (PAAHA). A Cosmosil MS-C 18 column (250×4.6 mm, 5 μm) was used under temperature control at 40°C. The mobile phase was H 2O CH 3CN CH 3COOH (100:3:1, pH 4.0) with a flow-rate of 1.5 ml/min. The excitation and emission wavelengths for fluorescence detection were set at 270 and 350 nm, respectively. Plasma samples (200 μl) were acidified by the addition of 150 μl of 1 M HClO 4 solution containing salicylic acid (SA) as the internal standard. After centrifugation, 30 μl of the supernatant were injected onto the column. Using this method, PABA and its three metabolites could be determined within 25 min. Within the investigated concentration ranges of PABA (0.1–50 μg/ml), PAABA (0.2–50 μg/ml), PAHA (0.1–50 μg/ml) and PAAHA (0.5–50 μg/ml), good linearity ( r>0.99) for the standard curves was obtained. The validation of this method showed coefficient of variance (C.V.) that was well below 15% for all compounds. After intravenous (i.v.) administration of PABA (20 mg/kg) to rabbits ( n=7), PABA followed a one-compartment open model elimination with a half-life of10.90±1.03 min. The mean half-lives for PAABA, PAHA and PAAHA were24.61±6.42, 12.81±6.04 and11.27±2.77 min, respectively.

Derivative linear variable-angle scanning fluorescence spectrometry for the determination of closely overlapping drug mixtures

Derivative variable-angle synchronous fluorescence spectrometry is developed to improve the selectivity of fluorescence measurements without loss of sensitivity. The first derivative variable-angle synchronous scanning permits the rapid simultaneous determination of p-aminobenzoic acid, salicylic acid and gentisic acid in a mixture from a single spectrum based on a single scan. The analyses were performed in aqueous medium at pH 7 provided by the addition of phosphate buffer solution. A complete and exhaustive statistical analysis of the experimental data was realized to demonstrate the validity of the method.

Reversed-phase liquid chromatographic method for the determination of p-aminobenzoic acid and anthranilic acid in urine: application to the investigation of exocrine pancreatic function

Exocrine pancreatic function can be assessed by determining the recovery in urine of p-aminobenzoic acid (PABA) following the oral administration of (N-benzoyl-L-tyrosylamino)benzoic acid (bentiromide). However, misleadingly abnormal results often occur in patients with abnormal intestinal, liver and renal function. Co-administration of 14C-PABA and the determination of the ratio of the recoveries of PABA to 14C-PABA, the PABA excretion index (PEI), has been used to eliminate these misleading results. Unfortunately, this has the disadvantage of exposing patients to radioactivity. We report the development and optimization of a modified test in which anthranilic acid, the ortho isomer of aminobenzoic acid, is substituted for the radiolabelled PABA. PABA and anthranilic acid in urine are determined by a C18 reversed-phase HPLC method. Peak detection is carried out at 254 nm. The method is specific for PABA and anthranilic acid, precise and fairly rapid. The PABA excretion index values in patients with pancreatic steatorrhoea (0.18–0.43) determined using the new liquid chromatographic method were clearly separated from those in healthy controls (0.63–1.14).

More on determination of p-aminobenzoic acid in urine.

More on determination of p-aminobenzoic acid in urine.

Assay of p-aminobenzoic acid with aromatic N-haloamines

The organic sulphonyl haloamines chloramine-T, bromamine-T and bromamine-B were used for the determination of p-aminobenzoic acid in aqueous solution. The proposed back-titration methods, which are based on the oxidation of p-aminobenzoic acid, are simple, fairly rapid and reproducible with an error of ±1%. The reactions involve a four-electron change and the oxidation products were identified. The effects of pH and the presence of some foreign ions, and also pyridoxine, pyridoxalamine, glycerol and alcohol, on the oxidation were studied.

Quantitative determination of p-aminobenzoic acid in solutions of novocaine by thin-layer chromatography

Quantitative determination of p-aminobenzoic acid in solutions of novocaine by thin-layer chromatography

Determination of p-aminobenzoic acid by room temperature solid surface phosphorescence

p-Aminobenzoic acid and several other molecules were found to phosphoresce at room temperature when adsorbed on sodium acetate. A unique phosphorimetric method is described for determining p-aminobenzoic acid without separation in multicomponent vitamin tablets. The reflected phosphorescence of p-aminobenzoic acid adsorbed on sodium acetate was measured in the quantitation step. The method is rapid, very selective, and sensitive for p-aminobenzoic acid. The limit of detection is about 0.5 ng per sample spot and the relative standard deviation is 2.4% at 5 mg per tablet. p-Hydroxy-benzoic acid, folic acid, and the benzamide of p-aminobenzoic acid also exhibited room temperature phosphorescence when adsorbed on sodium acetate. Phosphorescence data on these molecules are reported.

Determination of p-aminobenzoic acid in urine. A student laboratory experiment.

Knowledge of scientific literature reveals the increasing prominence of the application of analytical techniques to the determination of drugs in biological fluids, yet few experiments are designed for students interested in drug analysis. This article describes such an experiment.

Determination of p-Aminobenzoic Acid in Feeds

Abstract Collaborative studies were conducted on a revised method for p-aminobenzoic acid (PABA) in feeds. PABA is diazotized and coupled with N-1-naphthylethylenediamine dihydrochloride to form a red complex that provides both a qualitative test and a spectrophotometric assay. The PABA is extracted with a 10% hydrochloric acid solution and the alkaline hydrolysis step is eliminated. Results were close to the labeled drug content, although the aged feed evidenced drug instability. The revised method is recommended for adoption as official, first action.