Determination of phytic acid based on inhibition of crystalline growth of calcium oxalate monohydrate

It was found that the crystalline growth of calcium oxalate monohydrate seed crystals is strongly inhibited by the presence of phytic acid. The kinetics of crystal growth were followed potentiometrically using a calcium ion-selective electrode. Investigation of the process led to the development of a kinetic method for the determination of phytic acid (30–600 ng ml^?1). The procedure was applied to the direct determination of phytic acid in urine and in a pharmaceutical product.     

Fluorimetric determination of phytic acid in urine based on replacement reaction

A sensitive fluorimetric method for determination of phytic acid in human urine samples was described. The method was based on a fluorimetric replacement reaction, in which the added phytic acid replaced the Cu²⁺ ion from Cu²⁺-gelatin complex, liberating the fluorescent gelatin molecule. The fluorescence of the solution was accordingly recovered proportionally to the amount of the foreign phytic acid. The excitation wavelength was 273.5 nm and the characteristic emission wavelength was 305.0 nm, respectively. The calibration graph was obtained by plotting the recovered fluorescent intensity at maximum 305.0 nm against the added standard phytic acid, and was divided into two sections. One section was linear over the range of 0.40-2.40 mg L⁻¹ with a linear regression equation of I_f = −0.895 + 15.146c (R² > 0.9993), and the other over the range of 2.40-9.20 mg L⁻¹ with a linear regression equation of I_f = −29.526 + 26.113c (R² > 0.9996), respectively. The relative standard deviation (R.S.D.) at 95% confidence degree for a 2.0 mg L⁻¹ of standard phytic acid within 1 month was less than 1.26% (n = 5), indicating the procedure is reproducible. The detection and the quantification limits of phytic acid were estimated to be 0.23 and 0.40 mg L⁻¹, respectively. The proposed method was applied to the determination of phytic acid in urine samples and the found concentrations of phytic acid in urine were in the range of 0.49-0.75 mg L⁻¹ with recoveries of 96.2-108.8%. Comparison of the obtained results with the reported HPLC was performed, indicating the proposed method was reliable.     

Polarographic Determination of Inorganic Phosphorus in Phytic Acid

Abstract

A method for the determination of inorganic phosphorus in phytic acid by polarography was developed. The mechanism of Mo/Sb/P polarographic behaviour has been studied. It is one of the most sensitive analytical methods of phosphorus at present. The limit of detection is 8x10^?9 g/ml. This method has been used in the determination of inorganic phosphorus in phytic acid and result is found satisfactory.     

Fluorimetric determination of phytic acid based on the activation of the oxidation of 2,2'-dipyridyl ketone hydrazone catalysed by Cu(II)

Phytic acid exerts an activation effect on the oxidation of 2,2'-dipyridyl ketone hydrazone catalysed by Cu(II) ion and the oxidation product is highly fluorescent. A fixed time method for the fluorimetric determination of phytic acid based on this effect is described. The calibration graph is linear over the range 0.05-0.6 mg l-1 phytic acid, resulting in a limit of detection of 0.03 mg l-1 phytic acid. The relative standard deviation is in the range 1.4-1.8%, depending on the sample analysed. The method was successfully applied to the determination of phytic acid in human urine (20 samples) and food samples (nine different products). The results obtained for urine samples ranged from 0.31 to 3.6 mg l-1 phytic acid and for food samples from 3.8 to 22 mg g-1 phytic acid. This is the first procedure to be reported for the determination of phytic acid based on fluorimetric measurements.     

A Simple Gas Chromatographic Method for the Measurement of Dichloroacetic Acid in Plasma or Urine

Abstract

A method has been developed for measurement of dichloroacetic acid in plasma or urine. The procedure is based on derivatization of dichloroacetic acid with methanol-boron trifluoride, extraction of the resulting methyl ester and gas chromatography. The method has good accuracy and precision, and can be used to determine concentrations as low as 0.04 μg/ml.     

Determination of Aspirin,Salicylic Acid,Salicyluric Acid,and Gentisic Acid in Human Plasma and Urine by High Pressure Liquid Chromatography

Abstract

A method has been developed to simultaneously determine aspirin, salicylic acid, salicyluric acid, and gentisic acid concentrations in human plasma and urine. An extraction and dry-down step prepare the sample for resolution by reverse-phase high pressure liquid chromatography. The column effluent is monitored by both ultraviolet absorbance and fluorescence to optimize sensitivity and specificity for the compounds of interest.     

Enzymatic—spectrophotometric determination of phytic acid with phytase from Aspergillus ficuum

A method to determine phytic acid in the range 3–60 μM based on the spectrophotometric determination of inorganic phosphate with vanadate and molybdate, after liberation by enzymatic hydrolysis of phytic acid with phytase from Aspergillus ficuum at pH 2.5 and 37 °C is reported. The method has been applied successfully to determine phytic acid in wheat flour and in a pharmaceutical product.     

Thermal and Potentiometric Titrations of Phytic Acid

Abstract

Values for the ionization constants and the heats of ionization of phytic acid (inositol hexaphosphate) have been determined by simultaneous potentiometric and thermal titration in a titration microcalorimeter. The potentiometric results are in substantial agreement with those found by discontinuous titration; the heat liberated from pH 10.4 to 6.8 is essentially that found using a batch microcalorimeter. Ionization of phytic acid may be generally characterized as having five groups similar to pK of phosphoric acid, two groups similar to pK2 of phosphoric acid and 4 groups similar to pK4 of pyrophosphoric acid. A single group has pK ～ 5 with ΔH_i ～ -1.1 kcal/mol.     

Synchronous fluorescence analysis of phytate in food

A novel synchronous fluorescence method is described for determination of phytic acid in food samples. It is based on the formation of a ternary complex between phytate, 1,10-phenanthroline (phen) and Fe³⁺. The synchronous fluorescence intensity of the solution was accordingly enhanced proportionally to the increased phytate concentration. Synchronous luminescence spectroscopy was adopted in the study, and the Δλ was set to 40 nm. The calibration graph is linear from 0.33 to 32 mg L^?1 with a linear equation of I _f?=?8.770?+?2.980c (R ²?>?0.9994). The method was applied to determine phytate in food samples and the found concentrations of phytic acid in food were in the range of 4.62–24.08 mg g^?1 with recoveries of 92.2%–98.3%. The control experiments were performed using UV-spectrophotometry method, and the results showed the method to be reliable.     

Minimum handling method for the analysis of phosphorous inhibitors of urolithiasis (pyrophosphate and phytic acid) in urine by SPE-ICP techniques

Pyrophosphate (PPi) and phytic acid (IP6) are natural phosphorous compounds with growing interest in the biomedical field due to their ability as potential inhibitors of urolithiasis among others. Existing methodologies for their evaluation show inconveniences mainly associated with sample treatment, matrix interferences and lack of resolution. The objective of the present work is the validation of a new method to determine both inhibitors in urine samples selectively and its application to the diagnosis of lithiasic patients. After urine purification by an off-line anion exchange solid phase extraction (SPE), based in an appropriate acidic elution gradient, the phosphorous compounds were analyzed by ³¹P measurements by inductively coupled plasma mass spectrometry (ICP-MS) in the purified urine extracts. Linear range and limit of detection obtained were adequate for the analysis of the physiological amounts of the compounds in urine. The method was successfully applied to human urine samples, resulting in adequate accuracy and precision and allowing for the analysis of phosphorus inhibitors of urolithiasis in urine. The method simplicity and high sample throughput leads to a clear alternative to current determinations of the mentioned species in urine. Moreover, PPi and IP6 concentrations found in patients suffering from oxalocalcic urolithiasic were significantly lower than those for healthy controls, supporting the fact that the risk for oxalocalcic urolithiasis increases when urinary phosphorus inhibitors decrease. Thus, speciation of phosphorus inhibitors of urolithiasis in urine of stone formers can be performed, which is of unquestionable value in diagnostic, treatment and monitoring of urolithiasis.     

Hydrolysis of Phytic Acid by Microwave Treatment: Application to Phytic Acid Analysis in Pharmaceutical Preparations

The acid hydrolysis of phytic acid in a Teflon reactor using a domestic microwave oven has been studied and compared with other reported procedures. In 0.44 M HCl quantitative hydrolysis was achieved with six heating stages of 2 min each. A lower yield was obtained with H₂SO₄and HNO₃. The analytical use of this hydrolysis to determine phytic acid by indirect determination of phosphate has been demonstrated by analysis of three pharmaceutical formulations. No sample pretreatment other than obtaining a homogeneous suspension was necessary.     

High Pressure Liquid Chromatographic Assay for Salicylic Acid and its Metabolites in Rat Urine

Abstract

An HPLC method for the determination of salicylic acid (SA), gentisic acid (GA), salicyluric acid (SU), and salicyl acyl glucuronide (SAG) in rat urine was developed. The method consisted of extracting SA, GA, and SU from acidified urine into 50:50 mixture of ethyl acetate and butyl chloride. Salicyl acyl glucuronide was extracted from neutral urine after conversion to salicyl hydroxamic acid with hydroxylamine. Salicyl phenolic glucuronide was estimated indirectly as the difference between total salicylate and sum of the four constituents mentioned above. Chromatographic separation was done on a C₁₈ column with U.V. detection at 310 nm using a mobile phase consisting of 5–10% acetonitrile in 3% glacial acetic acid. The extraction recovery of these compounds from spiked urine ranged from 90–108%. The detection limits were 10 μg/ml for GA, SU and SA, and 2.5 μg/ml for SHA. The method was applied to the study of salicylic acid metabolism in the rat.     

The Determination Ofritalinic Acid in Urine by Gas Chromatography

Abstract

A gas chromatographic method for the analysis of ritalinic acid, the major metabolite of methylphenidate, in urine has been developed. Solid phase extraction is employed to afford high recovery of ritalinic acid. The method has a lower limit for reliable quantitation of 1 μ/ml. The reliability and sensitivity of this method make it suitable for human studies.     

High-Performance Liquid Chromatographic Determination of SAZ-VII-23, A Novel Antiarrhythmic Agent,in Dog Plasma and Urine

Abstract

A HPLC method has been developed to determine the concentrations of SAZ-VII-23 (3-benzoyl-7-isopropyl-3,7-diazabicyclo[3.3.1]nonane HClO₄), a novel antiarrhythmic agent, in dog plasma and urine. Plasma treated with acetonitrile and alkalinized urine were extracted with chloroform- propanol (9:1). An aliquot was injected on to HPLC system using a C₆ reversed-phase column and acetonitrile-methanol-37.5 mM phosphate buffer, pH 6.8 (28.5:28.5:43 v/v) containing 4.0 mM triethylamine as mobile phase. Detection wavelength was 255 nm. The linear range were 0.04–8 μg/ml, and the lower limit of quantitation was 0.04 μg/ml in plasma and urine, respectively. The method was applied to determine plasma and urine concentrations and preliminary pharmacokinetic profiles of SAZ-VII-23 in a dog.     

Urinary Uric Acid Determination by Reversed-Phase High Pressure Liquid Chromatography

Abstract

Reversed-phase high pressure liquid chromatography with UV detection was proven to be a powerful method for the separation and quantitation of urinary uric acid. We have compared three different treatments for urine samples previous chromatographic injection: alkaline methanol extraction, ethylacetate extraction and centrifugation. It was also studied storage conditions for urine samples.

Our findings show that the method has high specificity and reproducibility for urinary uric acid. Samples are stables and require only centrifugation previous injection to the chromatograph.     

A specific micromethod for the determination of phytic acid in biological material

A method for the quantitative determination of phytic acid in biological material is described. The method permits a determination of phytic acid in quantities below 0.1 mg even if the material contains closely related compounds includingmyo-inositol pentakisphosphate.

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Eine spezifische Mikromethode für die Bestimmung von Phytinsäure in biologischem Material

Zusammenfassung Es wird eine Methode zur quantitativen Bestimmung von Phytinsäure in biologischem Material beschrieben. Die Methode erlaubt die Bestimmung von Phytinsäure in Mengen von weniger als 0.1 mg, selbst wenn das Untersuchungsmaterial nahe verwandte Substanzen wie z. B.myo-Inositpentakisphosphat enthält.

     

High-Performance Liquid Chromatographic Determination of Clavulanic Acid in Human Serum and Urine Using a Pre-Column Reaction with 1, 2, 4-Triazole

Abstract

A reversed-phase high-performance liquid chromatographic (RP-HPLC) assay for the determination of clavulanic acid in serum and urine is described. The clavulanic acid was assayed by reacting the sample with 1, 2, 4-triazole reagent which rapidly produces a derivative that has its UV absorption maximum at 317 nm. The resulting product was separated in a RP-18 column (μ-Bondapak, 10 μm) and detected at 313 nm. The method was applied to assays of clavulanate in serum and urine, and is reproducible with a lower limit of quantitation of 0.1 μ/Ml.     

A Semi-Automated Colorimetric Method for the Analysis of Dihydroxyphenylacetic Acid (DOPAC) in Urine of Parkinsonian Patients Receiving L-Dopa

Abstract

An analytical system is presented which permits the separation and analysis of urinary dihydroxyphenylacetic acid (DOPAC). This method is suitable for analyzing the urine from both normal and Parkinsonian patients receiving L-Dopa.     

Revised HPLC Determination of Atenolol in Plasma and Urine

Abstract

An HPLC method for analysis of atenolol in human plasma and urine is presented. Based on alkaline extraction, acid backextraction and reverse phase ion-pair chromatography this method is quite specific for atenolol. For a 0.5 ml plasma sample the sensitivity ranges from 20 ng/ml in fasted healthy volunteers to 50 ng/ml in various groups of patients. A sensitivity in urine of 1.0 mcg/ml was sufficient for all samples studied. As presented this method has been used in several clinical pharmacokinetic studies involving hundreds of samples.     

Quantitation of Benzodiazepine Hydrolysis Products in Urine Using Solid-Phase Extraction and High Performance Liquid Chromatography

Abstract

Solid-phase extraction and high performance liquid chromatography (HPLC) were used to indirectly (via products of acid hydrolysis) confirm the presence of benzodiazepine metabolites in the urine of patients who had received overdoses of these compounds. The use of solid-phase extraction method for quantitation of benzodiazepine hydrolysis products in urine offers numerous advantages in comparison to extraction with chloroform. The chromatograms of urine extracts were free of interferences. The recoveries of the benzodiazepine hydrolysis products and the internal standard were greater than 96%, which makes this method highly reliable for quantitative analytical purposes.