scholarly journals Investigating matrix interference in the pharmacopeial limit test for aluminum in citric acid: a re-examination, for revision of the method

Pharmacia ◽  
2022 ◽  
Vol 69 (1) ◽  
pp. 9-13
Author(s):  
Theerasak Rojanarata ◽  
Kittithat Maithongdee ◽  
Nattapong Yuwansri ◽  
Sirada Kaewprasert ◽  
Thana Thanayutsiri ◽  
...  
Keyword(s):  
Citric Acid ◽  
Solvent Extraction ◽  
Acid Solution ◽  
Acid Solutions ◽  
Matrix Interference ◽  
Citric Acid Solution ◽  
Metal Chelating ◽  
Limit Test ◽  
The Matrix ◽  
Blank Solution

In many pharmacopoeias, the limit test used for determining the level of aluminum in citric acid labeled for use in the manufacture of dialysate, is based on solvent extraction using 8-hydroxyquinoline and measurement of fluorescence. However, the fluorescence intensity (F.I.) readout from the extract of citric acid samples has been found to be highly dubious, showing low value, and even lower than that of a blank solution. The aim of this work therefore was to examine what effects the matrix has on the test. The comparison of the two standard curves of aluminum solutions in water, against those prepared in citric acid solutions revealed that they differed greatly in terms of slope and y-intercept. In addition, the F.I. values on the plot of the citric acid solution were much lower than that prepared in the water. In another experiment, a decrease in the F.I. of aluminum solution was clearly seen when the co-existing concentration of citric acid was increased. The results inferred that citric acid interfered with the test due to its acidity and metal-chelating capabilities. Based on this evidence, the pharmacopeial limit test for aluminum in citric acid should be revised; otherwise, it could yield results that underestimate aluminum levels and lead to inaccurate conclusions

Solubility of Phosphorus in Citric Acid Solution as an Index of Biological Availability

1979 ◽  
Vol 16 (5) ◽  
pp. 290-292 ◽  
Author(s):  
Minoru YOSHIDA ◽  
Michiyuki ISHIKAWA ◽  
Hiroki NAKAJIMA ◽  
Saburo HOTTA
Keyword(s):  
Citric Acid ◽  
Acid Solution ◽  
Biological Availability ◽  
Citric Acid Solution

scholarly journals Kinetic Study in Atmospheric Pressure Organic Acid Leaching: Shrinking Core Model versus Lump Model

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 613
Author(s):  
Kevin Cleary Wanta ◽  
Widi Astuti ◽  
Indra Perdana ◽  
Himawan Tri Bayu Murti Petrus
Keyword(s):  
Citric Acid ◽  
Acid Solution ◽  
Acid Leaching ◽  
Core Model ◽  
Shrinking Core Model ◽  
Citric Acid Solution ◽  
Lumped Model ◽  
Leaching Process ◽  
Shrinking Core ◽  
Simulation Results

The kinetics study has an essential role in the scale-up process because it illustrates the real phenomena of a process. This study aims to develop a mathematical model that can explain the mechanism of the leaching process of laterite ore using a low concentration of the citric acid solution and evaluate that model using the experimental data. As a raw material, this process used powder-shaped limonite laterite ores with a size of 125–150 µm. The leaching process is carried out using 0.1 M citric acid solution, F:S ratio of 1:20, and a leaching time of 2 h. The temperature parameter was varied at 303, 333, and 358 K. The experimental results showed that the higher the operating temperature, the higher the extracted nickel. The results of this experiment were used to evaluate the shrinking core kinetics model and the lumped model. The simulation results for both models show that the lumped model can provide better simulation results. Quantitatively, the percentage of errors from the shrinking core model is around 3.5 times greater than the percentage of errors from using the lumped model. This result shows that in this leaching process, the process mechanism that occurs involves the reactant diffusion step and the chemical reactions step; those steps run simultaneously.

Dissolution mechanism of various elements from steelmaking slag into citric acid solution

2019 ◽  
Vol 116 (3) ◽  
pp. 321
Author(s):  
Ningning Lv ◽  
Chang Su ◽  
Hui Kong ◽  
Jinxing Yang ◽  
Weiming Liu ◽  
...  
Keyword(s):  
Citric Acid ◽  
Acid Solution ◽  
Mass Balance ◽  
Dissolution Mechanism ◽  
Steelmaking Slag ◽  
Citric Acid Solution ◽  
Initial Concentration ◽  
Predominant Species ◽  
Dissolution Ratio ◽  
The Relationship

To recycle valuable elements from steelmaking slag, their dissolution mechanism into citric acid solution has been investigated. First, the relationship between dissolution ratio of each element and initial concentration of citric acid (ci) was studied. Then, the concentrations of each species in solution were calculated through mass balance. Based on these results, it can been seen that whenci = 0.00104 mol/L, Ca2+, CaCit−, MgCit−, FeH2PO42+and CaHPO4are the predominant species in solution, and Ca5(PO4)3(OH)(s) precipitate can form easily, which may suppress the dissolution of elements. Whenciincreases to 0.0104 mol/L, dissolution ratio of each element increases significantly, except for iron. And the predominant species correspondingly change to Ca2+, Mg2+, CaCit−, MgCit−, H2Cit−, H3Cit and FeH2PO42+.

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