scholarly journals Preconcentration of ultra-traces of Cu(II) in water samples using SBA-15 sorbent modified with a thiocarbohydrazide ligand prior to determination by flame atomic absorption spectrometry

2019 ◽  
Vol 84 (5) ◽  
pp. 489-501
Author(s):  
Mahmood Payehghadr ◽  
Haghgoo Qezelje ◽  
Farzaneh Nourifard ◽  
Abdolmohammad Attaran ◽  
Mehdi Kalhor
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Food Samples ◽  
Limit Of Quantification ◽  
Breakthrough Volume ◽  
Flame Atomic Absorption ◽  
Stirring Time

A simple, reliable and rapid method for the extraction of ultra-trace copper(II) using nanoporous SBA-15 sorbent modified with a thiocarbohydrazide ligand, and determination by flame atomic absorption spectrometry is presented. The optimum parameters of the method were obtained as pH of aqueous solution 5, sorbent amount 2 mg, stirring time 20 min and 0.4 M HCl solution as the eluent solvent. This method has a breakthrough volume greater than 1500 mL with a concentration factor of more than 300, linear range 0.8?2500.0 ?g L-1, limit of detection 0.253 ?g L-1 and limit of quantification 0.844 ?g L-1 for copper(II). The capacity of 2 mg of modified SBA-15was found to be 123.00?0.04 mg g-1. Standard deviations were 3.3, 2.3 and 2.1 % for 1, 2 and 4 ?g mL-1, respectively (n = 5). This method was successfully applied for the determination of copper(II) in different real samples, especially in the food samples.

Modern Methodological Approaches to Sample Preparation for the Determination of Trace Elements in Food Products and Plant Raw Materials

2021 ◽  
pp. 48-54
Author(s):  
NE Fedorova ◽  
MV Egorova ◽  
AS Rodionov
Keyword(s):  
High Resolution ◽  
Sample Preparation ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption ◽  
Homogeneity Of Variances ◽  
Limit Of Quantitation

Introduction. Various copper compounds are most widely used as plant protection agents in agriculture. From a hygienic point of view, information on excessive accumulation of copper in plants related to the use of a specific formulation of copper-containing pesticides is of interest. Our objective was to assess feasibility of increasing statistical significance of results of determining low residue levels of a copper-containing pesticide in apple samples by flame atomic absorption spectrometry using a high-resolution spectrometer in combination with developed approaches to sample preparation of plant-based foods, including homogenization with dry ice and microwave mineralization. Materials and methods: We analyzed 30 samples of apples collected in three different agro-climatic zones by flame atomic absorption spectrometry and electrothermal atomization atomic absorption spectrometry. Both methods were validated on 10 samples with added copper at levels 1-5 of the lower limit of quantitation. A statistical calculation was performed based on a simple Student’s test to assess the significance of differences between the results of measurements by flame and electrothermal techniques. Homogeneity of variances was estimated using the Fisher test to clarify the possibility of comparing two data sets. Results: The use of a technique of cryo-grinding and microwave decomposition in a microwave reactor in combination with a high-resolution continuum source atomic absorption spectrometry demonstrated a decrease in scattering and the limit of detection and better repeatability in the analysis of parallel samples. Results of statistical calculations confirmed the homogeneity of variances in data samples obtained for electrothermal and flame techniques, and the further Student’s t-test showed insignificant differences between the results of measurements obtained by FAAS and ET-AAS. Conclusion: Our findings prove that modern methods of sample preparation in combination with highly sensitive equipment allow a significant reduction in the limit of detection and scattering of test results.

scholarly journals Determination of Copper in Water and Plant Samples by Flame Atomic Absorption Spectrometry After Preconcentration on Octadecyl Silica Membrane Disks Modified with a Recently Synthesized Schiff's Base

2008 ◽  
Vol 91 (4) ◽  
pp. 865-870 ◽  
Author(s):  
Tayebeh Shamspur ◽  
Ali Mostafavi ◽  
Iran Sheikhshoaie
Keyword(s):  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Minimal Amount ◽  
Aqueous Samples ◽  
Silica Membrane ◽  
Flame Atomic Absorption

Abstract A simple, selective, reliable, and sensitive method for the determination of trace amounts of Cu2+ ions in aqueous samples is proposed. The Cu2+ ions are adsorbed quantitatively during the passage of aqueous samples through an octadecyl (C18) silica membrane disk modified by a symmetrical tetradentate Schiff base ligand, N,N'-bis(4-phenylazo salicylaldimine) 3-chloro-1,2-phenylenediamine (H2L). The retained Cu2+ ions were then stripped from the disk by elution with the minimal amount of nitric acid solution and determined by flame atomic absorption spectrometry. Various parameters, such as the effect of pH, flow rate, type and amount of eluent, and the effects of various cationic interferences on the recovery of ions were studied. The proposed method permitted large enrichment factors (about 550 and higher). The limit of detection of the method was 1.5 102 g/L. The use of the same disk modified with 6 mg H2L for at least 30 times showed no change in the recovery of Cu2+ ions. The accuracy of the method was confirmed by determination of Cu2+ ions in standard samples [National Institute of Environmental Studies (NIES) No. 2 and Nippon Keikinzoku Kogyo (NKK) No. 920]. The results demonstrated good agreement with certified values.

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