AMBIENTUM BIOETHICA BIOLOGIA CHEMIA DIGITALIA DRAMATICA EDUCATIO ARTIS GYMNAST. ENGINEERING EPHEMERIDES EUROPAEA GEOGRAPHIA GEOLOGIA HISTORIA HISTORIA ARTIUM INFORMATICA IURISPRUDENTIA MATHEMATICA MUSICA NEGOTIA OECONOMICA PHILOLOGIA PHILOSOPHIA PHYSICA POLITICA PSYCHOLOGIA-PAEDAGOGIA SOCIOLOGIA THEOLOGIA CATHOLICA THEOLOGIA CATHOLICA LATIN THEOLOGIA GR.-CATH. VARAD THEOLOGIA ORTHODOXA THEOLOGIA REF. TRANSYLVAN
Rezumat articol ediţie STUDIA UNIVERSITATIS BABEŞ-BOLYAI
În partea de jos este prezentat rezumatul articolului selectat. Pentru revenire la cuprinsul ediţiei din care face parte acest articol, se accesează linkul din titlu. Pentru vizualizarea tuturor articolelor din arhivă la care este autor/coautor unul din autorii de mai jos, se accesează linkul din numele autorului.
Autori: MARIN SENILA, OANA CADAR, MARIA-ALEXANDRA HOAGHIA, ZAMFIRA DINCA, LACRIMIOARA SENILA, IOAN ASCHILEAN, CECILIA ROMAN.
DOI: 10.24193/subbchem.2021.2.07
Published Online: 2021-06-30
Published Print: 2021-06-30
pp.81-94
FULL PDF
ABSTRACT: The paper presents the validation of a method for the determination of exchangeable cations (K+, Na+, Ca2+ and Mg2+) in zeolites by inductively coupled plasma optical emission spectrometry (ICP-OES), after extraction in ammonium chloride solution. Amongst the analytical techniques that can be used for exchangeable cations measurement, ICP-OES provides rapid, robust, multi-element analysis on a wide range of concentrations. The exchange capacity is one of the most important parameters of zeolites since it indicates their adsorption capacity in different processes. Method validation is an essential requirement for testing laboratories in order to provide trustworthy results in accordance with ISO/IEC 17025:2017 standard. The main figures of merit were studied, and the measurement uncertainty was assessed. The selectivity assay showed no significant non-spectral matrix effect. The linearity study was conducted for the calibration curves in the range of 0.02–20 mg L−1 for each exchangeable cation. Limits of quantification were 0.005 mEq 100 g-1 for Na+, 0.011 mEq 100 g-1 for Mg2+, 0.002 mEq 100 g-1 for K+, 0.003 mEq 100 g-1 for Ca2+. Relative standard deviations of repeatability (RSDr) (n=6 parallel samples) were 4.50 % for Na+, 4.43 % for Mg2+, 6.55 % for K+ and 5.53 % for Ca2+. Recoveries (%) estimated using a certified reference material (CRM BCS-CRM 375/1), for total content of cation oxides were in the range 92–103 %. Fourteen zeolite samples from Racos deposit, Romania were analysed, and according to the chemical composition and X-ray diffraction the main mineral in zeolitic tuffs is clinoptilolite-type. The obtained figures of merit demonstrate that the method has a suitable level of precision and accuracy for the intended purpose.
Key words: zeolites, exchangeable cations, ICP-OES, method validation, cation exchange capacity
