TRACE ELEMENT ANALYSIS OF HUMUS-RICH NATURAL WATER SAMPLES

Humus-rich natural water samples, containing high concentrations of dissolved organic carbon
(DOC), are challenging for certain analytical methods used in trace element analysis, including
hydride generation methods and electrochemical methods. In order to obtain reliable results, the
samples must to be pretreated to release analytes from humic acid complexes prior to the
determination. In this study, methods for both pretreatment and analysis steps were developed.
Arsenic is a toxic element and therefore its determination even at low concentration levels is
important in environmental monitoring. Arsenic complexed with humic substances is not likely to
form volatile hydrides quantitatively during borohydride reduction. In this study, natural water
samples were digested with microwave-assisted digestion method prior to analysis by hydride
generation inductively coupled plasma mass spectrometry (HG-ICP-MS). In addition, a dual mode
sample introduction system was used to study internal standardization in order to correct signal
variations during the measurement of arsenic with HG-ICP-MS.
A novel nano-TiO2 catalyzed ultraviolet light emitting diode (UV-LED) digestion device was
developed to apply green chemistry principles in sample preparation. The method consumes less
harmful reagents and less energy than traditional techniques. The DOC removal efficiency was
studied as a function of pH, irradiation time and hydrogen peroxide concentration. Recoveries of
spiked heavy metals and hydride forming elements were studied. UV-LED technology is growing
rapidly, and new catalytic semiconductor materials for photocatalysis are being developed. In this
study, the effects of synthesis method variables on the properties of ZnO nanopowders were
investigated.


ISBN-10:
9789526216805
Julkaisusarja:
ACTA UNIVERSITATIS OULUENSIS A Scientiae Rerum Naturalium
Kustantaja:
Oulun yliopisto
Painos:
Osajulkaisuväitöskirjan yhteenveto-osa
Painovuosi:
2017
Sivumäärä:
62
Tekijät:
HAVIA JOHANNA
Viivakoodi 9789526216805
Tuotekoodi 024603
Tekijä HAVIA JOHANNA
15,50 €