Effectiveness of inductively coupled plasma optical emission spectrometry (ICP OES) in macro and microelements assessment in water
The suitability of the method was evaluated for determining 15 elements (aluminum, stibium, arsenic, boron, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, selenium, argentum, sodium, zinc) using atomic emission inductive coupling plasma was evaluated (ICP OES) and defined validation characteristics of the method, namely: detection limit, quantification limit, accuracy, correctness, convergence, reproducibility, selectivity, linearity, and operating range. Modification of the method allowed to exclude the stage of filtration of the sample to reduce the sample preparation time, model the nitric acid content in it, and introduce the use of the internal indium standard, taking into account the proximity of atomic masses of individual elements. This allowed us to level the instrumental drift, select the most favorable emission wavelengths for 10 of the 15 elements, and get a clearer signal and a more accurate result. This method is simple, sensitive, practical, and universal, which is confirmed by LOD and LOQ data. Approbation of this method to determine the content of individual elements in drinking water showed that it demonstrates good selectivity, accuracy, and linearity in the concentration range of 1-1000 μg/l depending on the researched element. Using the method of atomic emission inductively coupled plasma (ICP OES) to determine the content of 15 mineral elements in drinking water, which came to the laboratory from the settlements of Ukraine, showed that in 2020–out of 105 samples in five were found to exceed the MRL of iron in 1.5-2.4 times, in 2021 from the analyzed 58 samples–in one sample the iron content exceeded the MRL almost two times. The got validation data meet the requirements of European directives.