scholarly journals Chlorine determination in medicinal plants by potentiometry with ion-selective electrode after microwave-induced combustion

2021 ◽  
Vol 5 (1) ◽  
pp. 19-25
Author(s):  
Mariele Samuel Nascimento ◽  
Gabriel Toneto Druzian ◽  
Rochele Sogari Picoloto ◽  
Paola Azevedo Mello ◽  
Erico M. M. Flores

A method based on microwave-induced combustion (MIC) was applied for medicinal plants digestion allowing further chlorine determination by potentiometry using ion-selective electrode (ISE). Sample masses ranging from 500 to 1000 mg were evaluated for MIC digestion. Water and 10, 25, 50, and 100 mmol/L NH4OH were investigated as absorbing solutions. The accuracy of the proposed method was evaluated by using certified reference materials (CRMs), by recovery tests (500 µg/g), and also by comparison with the results obtained by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted alkaline extraction (MAE). Using water or NH4OH solutions (10 to 100 mmol/L), recoveries close to 100% and relative standard deviation lower than 5% were obtained. Results were in agreement with CRMs values (better than 95%) and also with those values obtained by using the MAE method. The main advantage of the proposed method was the complete combustion of high sample mass (1000 mg) resulting in low quantification limit (12.5 µg/g) and chlorine determination at low concentration by ISE. Another advantage of the proposed method was the high chlorine stability in digests (up to 30 days of storage) even using water as absorbing solution, which is in agreement with green analytical chemistry recommendations. Finally, the proposed MIC method was applied for commercial medicinal plants and the chlorine concentration was in the range of 59.4 ± 1.4 to 2038 ± 70 µg/g. The proposed MIC method was considered suitable for quality control for chlorine determination in medicinal plants.

2008 ◽  
Vol 91 (6) ◽  
pp. 1397-1401 ◽  
Author(s):  
Daniel Hammer ◽  
Daniel Andrey

Abstract The performances of 2 official methods for iodine analysis based on inductively coupled plasma-mass spectrometry (ICP-MS) and the ion-selective electrode (ISE) method were compared for milk-based products. The aim of the study was to determine the performance characteristics of both methods to check the labeled concentration of iodine. Good precision was found for both methods with highest relative standard deviation of repeatability (RSDr) at 2.3 and 2.7 for ISE and ICP-MS, respectively. Intermediate reproducibility (RSDiR), single laboratory within 6 different days, was also good with the highest values at 7.3 and 8 by ISE and ICP-MS, respectively. Measurement uncertainty was estimated based on the RSDiR data, and it was concluded that both methods were capable of determining iodine concentrations within an uncertainty below 20. The accuracy of the methods was determined by analyzing certified reference materials, in-house proficiency test samples, and commercial products. Both methods returned similar results when applied on freshly opened samples. In samples that had been opened and kept exposed to air during storage, ISE returned lower iodine concentrations than ICP-MS. In commercial samples, the linear regression between both methods was ISE 0.95 ICP-MS 0.060 for freshly opened samples and ISE 0.85 ICP-MS 0.069 for samples exposed to air. The tendency of ISE to return lower results than ICP-MS is explained by the fact that ISE is sensitive to iodide but does not measure iodine that may be bound organically to the matrix. This seems to be more pronounced in samples that were stored longer. Because in most countries iodine is labeled as total iodine, acceptance of an international standard based on the ICP-MS technique which takes all forms of iodine into account, is recommended. This would help to avoid any potential dispute on the accuracy of labeled iodine concentrations in finished products.


Nutrients ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1218 ◽  
Author(s):  
Ching Lai ◽  
Hazel Gardner ◽  
Donna Geddes

Sodium (Na), potassium (K), and the ratio Na:K in human milk (HM) may be useful biomarkers to indicate secretory activation or inflammation in the breast. Previously, these elements have been measured in a laboratory setting requiring expensive equipment and relatively large amounts of HM. The aim of this study was to compare measurements of Na and K in HM using inductively coupled plasma optical emission spectrometry (ICP-OES) with small portable ion selective electrode probes for Na and K. Sixty-five lactating women donated 5 mL samples of HM. Samples were analyzed with two ion selective probes (Na and K) and also ICP-OES. The data were analyzed using paired t-test and Bland–Altman plots. Na concentrations were not significantly different when measured with ion selective electrode (6.18 ± 2.47mM; range: 3.59–19.8) and ICP-OES (5.91 ± 3.37 mM; range: 2.59–21.5) (p = 0.20). K concentrations measured using the ion selective electrode (11.7 ± 2.21 mM: range: 7.69–18.1) and ICP-OES (11.1 ± 1.55 mM: range: 7.91–15.2) were significantly different (p = 0.01). However, the mean differences of 0.65 mM would not be clinically relevant when testing at point of care. Compared to ICP-OES, ion selective electrode is sufficiently accurate to detect changes in concentrations of Na and K in HM associated with secretory activation and inflammation in the mammary gland.


2020 ◽  
Vol 16 ◽  
Author(s):  
Diogo L. R. Novo ◽  
Priscila T. Scaglioni ◽  
Rodrigo M. Pereira ◽  
Filipe S. Rondan ◽  
Gilberto S. Coelho Junior ◽  
...  

Background: Conventional analytical methods for phosphorus and sulfur determination in several matrices present normally analytical challenges regarding inaccuracy, detectability and waste generation. Objective: The main objective is proposing a green and feasible analytical method for phosphorus and sulfur determination in animal feed. Methods: Synergic effect between microwave and ultraviolet radiations during sample preparation was evaluated for the first time for the animal feed digestion associated with further phosphorus and sulfur determination by ion chromatography with conductivity detection. Dissolved carbon and residual acidity in final digests were used for the proposed method assessment. Phosphorus and sulfur values were compared with those obtained using conventional microwave-assisted wet digestion in closed vessels associated with inductively coupled plasma optical emission spectrometry and with those obtained using Association of Official Analytical Chemists International official method. Recovery tests and certified reference material analysis were performed. Animal feeds were analyzed using the proposed method. Results: Sample masses of 500 mg were efficiently digested using only 2 mol L -1 HNO3. The results obtained by the proposed method was not differing significantly (p > 0.05) from those obtained by the conventional and official methods. Suitable recoveries (from 94 to 99%), agreement with certified values (101 and 104%) and relative standard deviations (< 8%) were achieved. Phosphorus and sulfur content in commercial products varied in a wide range (P: 5,873 to 28,387 mg kg-1 and S: 2,165 to 4,501 mg kg-1 ). Conclusion: The proposed method is a green, safe, accurate, precise and sensitive alternative for animal feed quality control.


2017 ◽  
Vol 9 (23) ◽  
pp. 3497-3504 ◽  
Author(s):  
C. M. M. Santos ◽  
M. A. G. Nunes ◽  
A. B. Costa ◽  
D. Pozebon ◽  
F. A. Duarte ◽  
...  

Electrothermal vaporization (ETV) associated with inductively coupled plasma optical emission spectrometry (ICP OES) for elemental determination in medicinal herbs was investigated.


2021 ◽  
Vol 874 ◽  
pp. 50-57
Author(s):  
Asep Saefurohman ◽  
Buchari ◽  
Indra Noviandri

Methods for the quantitative determination of lanthanum that have been developed are generally spectroscopic methods such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray fluorescence spectrometry, which has relatively high operational costs. The feasibility of the potentiometric method using ion selective electrode (ISE) as an alternative method for lanthanum (III) determination needs to be studied because it is simple, easy to use, and has high sensitivity and selectivity. In this study, we developed ion selective electrode using PTFE membrane impregnated with tributyl phosphate (TBP) as ionophore. TBP is commonly used as a complexing agent for rare-earth ions in supported liquid membrane (SLM) separation process. We found that the compound can be used as an ionophore for ISE. This study aims to make a lanthanum ion selective electrode (III) (La-ISE) which has a Nernstian response. The parameters studied in the construction of this electrode were the effects of PTFE membrane immersion ionophore solution, ionic strength adjuster (ISA), and the inner solution composition. The performance parameters studied for the La-ISE were linear range, response time, detection limit, selectivity, and the lifetime of the electrode. Construction of the electrode begins with the preparation of the PTFE membrane as the main component. PTFE membrane was impregnated for 12 hours in the TBP solution having a concentration of 0.25 M or 0.50 M in kerosene. After it was dried, the membrane was attached to the end of the electrode tube with adhesive. Then, the electrode was filled with an internal solution containing a mixture of KCl 10-3 M with La (III) 10-3 M. The internal reference electrode was Ag/AgCl electrode. Before it was used, the electrode was soaked in a solution of La (III) 10-3 M for 12 hours.The effect of TBP concentration on the electrode performance was studied using two concentrations of TBP: 0.25 M and 0.50 M. The calibration curves obtained using both electrodes have good linearity. Nernst factor obtained from both electrodes is similar, although the Nernst factor obtained with an electrode having 0.50 M TBP closer to the theoretical value.ISA used in the measurement was KNO3. The effect of ISA on the performance of the electrode was studied using electrodes containing TBP with the concentration of 0.25 M or 0.50 M. The concentration of KNO3 used in this study was 0.01 M and 0.10 M. The Nernst factors obtained with electrodes containing 0.25 M TBP, in general, higher than those obtained with electrodes containing 0.50 M TBP in the same ISA. Electrode containing 0.50 M TBP resulted in the Nernst factor close to theoretical value when a measurement was conducted in 0.10 M KNO3.


2014 ◽  
Vol 1015 ◽  
pp. 570-573
Author(s):  
Xiao Juan Wei ◽  
Jian Ming Pan

A novel method for the determination of ruthenium in waste ruthenium-loaded carbon catalyst samples was established by inductively coupled plasma optical emission spectrometry after samples digested by Teflon pressure digestion vessel with aqua regia. Such experiment conditions were investigated as the influence of sample dissolution methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the limit of detection (LODs) of Ru for tested solution was 9 ng mL-1. The relative standard deviations (RSDs) for Ru was 2.12 % (CRu= 1 mg L-1, n = 7). The linear range of calibration graph for Ru and Zn was 0 ~ 100.00 mg L-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.


2014 ◽  
Vol 1004-1005 ◽  
pp. 1281-1284
Author(s):  
Xiao Juan Wei ◽  
Zhi Quan Tian

A novel method for simultaneous determination of ruthenium and zinc in catalysts for hydrogenation of benzene to cyclohexene was established by inductively coupled plasma optical emission spectrometry after sample digestion by high temperature fusion with Na2O2. Such experiment conditions were investigated as the influence of sample digestion methods, fusion time, fusion temperature, the dosage of Na2O2and interfering ions on the determination. Under the optimized conditions, the limits of detection (LODs) of Ru and Zn for tested solutions were 11 and 13 ng mL-1, respectively. The relative standard deviations (RSDs) for Ru and Zn were 2.01 and 2.35 % (CRu, Zn= 1 mg L-1, n = 7), respectively. The linear ranges of calibration graphs for Ru and Zn were 0.05 ~ 100.00 mg L-1and 0.04 ~ 50.00 mg L-1, respectively. The proposed method was applied to determine catalyst samples with good recoveries and satisfactory results.


2014 ◽  
Vol 1033-1034 ◽  
pp. 603-606 ◽  
Author(s):  
Jian Ming Pan ◽  
Xiao Juan Wei

A technique for determination of Ru in waste ruthenium catalysts using ICP-OES after sample digestion by high temperature fusion with NaOH-NaNO3mixture was described. Such experiment conditions were investigated as the influence of sample digestion methods, fusion time, fusion temperature, the dosage of NaOH-NaNO3mixture and interfering ions on the determination. Under the optimized conditions, the limits of detection (LODs) of Ru for tested solutions were 10 ng mL-1. The relative standard deviations (RSDs) for Ru were 2.01 (CRu= 1 mg L-1, n = 7). The linear ranges of calibration graphs for Ru were 0 ~ 100.00 mg L-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.


2014 ◽  
Vol 1033-1034 ◽  
pp. 599-602
Author(s):  
Chun Miao Shi ◽  
Xiao Juan Wei

A novel method for the determination of platinum in waste platinum-loaded carbon catalyst samples was established by inductively coupled plasma optical emission spectrometry after samples digested by Teflon pressure digestion vessel with aqua regia. Such experiment conditions were investigated as the influence of sample dissolution methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the limit of detection (LODs) of Pt for tested solution was 15 ng mL-1. The relative standard deviations (RSDs) for Pt was 2.35 % (CPt= 5 mg L-1, n = 7). The linear range of calibration graph for Pt was 0 ~ 150.00 mg L-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.


2018 ◽  
Vol 1 (01) ◽  
pp. 5-10 ◽  
Author(s):  
Ehsan Zolfonoun

In this work MWCNTs-Fe3O4 nanocomposite was used as an adsorbent for extraction and preconcentration of indium from aqueous solutions. The magnetic MWCNTs with adsorbed analytes were easily separated from the aqueous solution by applying an external magnetic field. After elution of the adsorbed analytes, the concentration of indium was determined using inductively coupled plasma optical emission spectrometry determination. The effects of pH, sorbent amount, eluent type, chelating reagent concentration, sample volume and time on the recovery of the In(III) were investigated. Under the optimum conditions, the detection limit for In(III) was 0.28 μg L−1. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was 3.1 %. The method was successfully applied for the determination of In(III) in environmental water samples.


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