Polypyrrole/phytase amperometric biosensors for the determination of phytic acid in standard solutions

Adenine nucleotides (ATP, ADP and AMP) play a central role in the regulation of metabolism and energy: they provide the energy balance of the cell, determine its redox state, act as allosteric effectors of a number of enzymes, modulate signaling and transcription factors and activate oxidation or biosynthesis substrates. A large number of methods have been developed to determine the level of ATP, ADP and AMP, but the most universal and effective method for the separation and analysis of complex mixtures is the reversed-phase high-performance liquid chromatography method (RP-HPLC). The aim of this study is to determine the optimal conditions for the qualitative separation and quantitative determination of standard solutions of ATP (1 mmol/l), ADP (0,5 mmol/l) and AMP (0,1 mmol/l) by RP-HPLC. The degree of separation of adenine nucleotides was estimated by the time of peak output in the chromatogram. To achieve the goal, the following tasks were set: assess the effect of the temperature of the analysis on the separation and change of the release time of the analytes in the chromatogram; determine the most optimal composition of the mobile phase for the separation of ATP, ADP and AMP in the chromatogram (the content of the organic solvent in the solution); to identify the effect of pH of the mobile phase on the separation of standard solutions of adenine nucleotides; set the optimal molarity of the mobile phase for the separation of ATP, ADP and AMP in the chromatogram. It was found that the temperature of the analysis does not affect the quality of peak separation, while the composition and pH of the mobile phase have a significant effect on the complete and clear separation of the studied nucleotides in the chromatogram. It was determined that the analysis temperature of 37°C and the mobile phase of 0.05 M KH2PO4 (pH 6.0) are optimal for separating the peaks of adenine nucleotides.

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Simultaneous Determination of Creatine and Creatinine using Monocrystalline Diamond Paste–Based Amperometric Biosensors

Analytical Letters ◽

10.1080/00032710600751016 ◽

2006 ◽

Vol 39 (11) ◽

pp. 2227-2233 ◽

Cited By ~ 9

Author(s):

Raluca‐Ioana Stefan‐van Staden ◽

Rahel Girmai Bokretsion

Keyword(s):

Simultaneous Determination ◽

Amperometric Biosensors ◽

Diamond Paste ◽

Monocrystalline Diamond

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New spectrophotometric method for the determination of hemoglobin A1 compared with a microcolumn technique.

Clinical Chemistry ◽

10.1093/clinchem/28.1.96 ◽

1982 ◽

Vol 28 (1) ◽

pp. 96-99 ◽

Cited By ~ 12

Author(s):

O Wålinder ◽

G Ronquist ◽

P J Fager

Keyword(s):

Phytic Acid ◽

Spectrophotometric Method ◽

Healthy Subjects ◽

Large Scale ◽

Glycosylated Hemoglobin ◽

Standard Curve ◽

Sugar Moiety ◽

Hemoglobin A1 ◽

The Mean

Abstract We compared a spectrophotometric kit method (Glycospec) for determination of glycosylated hemoglobin (HbA1) with a microcolumn kit method (Bio-Rad). The Glycospec method is based on the change in absorbance when phytic acid binds to hemoglobin A. With glycosylated hemoglobin there is no such change because the binding is blocked by the sugar moiety. Inter-assay CVs were 2-6% for both methods. In healthy subjects the mean (+/- SD) value for HbAl was about 1% higher with the spectrophotometric than the microcolumn method. For samples from 122 diabetics the correlation between values for HbAl obtained with the two methods was acceptable (r = 0.89), although the spectrophotometric technique yielded 2-4% higher values, a difference at least partly due to the absence of 2,3-diphosphoglycerate from the spectrophotometric standards. Adding 1.8 mmol of it per liter to these standards caused displacement of the standard curve; HbAl values then agreed well with those of the microcolumn method. The spectrophotometric procedure is easily automated, and therefore is well suited for large-scale analyses if problems with standards and calibration can be solved.

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

The Analyst ◽

10.1039/a901772k ◽

1999 ◽

Vol 124 (6) ◽

pp. 897-900 ◽

Cited By ~ 19

Author(s):

J. G. March ◽

B. M. Simonet ◽

F. Grases

Keyword(s):

Phytic Acid ◽

Fluorimetric Determination ◽

Dipyridyl Ketone

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Determination of Sugars in Distilled Spirits by GLC

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/51.4.925 ◽

1968 ◽

Vol 51 (4) ◽

pp. 925-927

Author(s):

Glenn E Martin ◽

Nicholas K Eib

Keyword(s):

Reducing Sugars ◽

Internal Standard ◽

Distilled Spirits ◽

Aoac Method ◽

Standard Solutions

Abstract The anomeric forms of glucose (α and β) and fructose were determined by GLC in both standard solutions and in distilled spirits, using sorbitol as an internal standard. The GLC method for fructose and α and β-glucose compares favorably with the AOAC method for concentrations from about 150 to 225 mg/100 ml. However, at concentrations below 100 mg/100 ml, the GLC method gives generally lower values, probably because the AOAC method measures the amount of reducing sugars and the GLC method measures only α and β-D-glucose and D-fructose

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Optimization of the Treatment of Wheat Samples for the Determination of Phytic Acid by HPLC with Refractive Index Detection

Journal of AOAC International ◽

10.1093/jaoac/92.3.873 ◽

2009 ◽

Vol 92 (3) ◽

pp. 873-878 ◽

Cited By ~ 3

Author(s):

Rosa Amaro ◽

Miguel Murillo ◽

Zurima Gonzlez ◽

András Escalona ◽

Lus Hernández

Keyword(s):

Refractive Index ◽

High Performance Liquid Chromatography ◽

Phytic Acid ◽

High Performance ◽

Substantial Improvement ◽

Significant Loss ◽

Phytic Acid Content ◽

Extraction Step ◽

Refractive Index Detection

Abstract The treatment of wheat samples was optimized before the determination of phytic acid by high-performance liquid chromatography with refractive index detection. Drying by lyophilization and oven drying were studied; drying by lyophilization gave better results, confirming that this step is critical in preventing significant loss of analyte. In the extraction step, washing of the residue and collection of this water before retention of the phytates in the NH2 Sep-Pak cartridge were important. The retention of phytates in the NH2 Sep-Pak cartridge and elimination of the HCl did not produce significant loss (P = 0.05) in the phytic acid content of the sample. Recoveries of phytic acid averaged 91, which is a substantial improvement with respect to values reported by others using this methodology.

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