Threshold Value Determination Using Machine Learning Algorithms for Ba Interference with Eu in Coal and Coal Combustion Products by ICP-MS

Abstract

Ba-based ion interference with Eu in coal and coal combustion products during quadrupole-based inductively coupled plasma mass spectrometry procedures is problematic. Thus, this paper proposes machine-learning-based prediction models for determination of the threshold value of Ba interference with Eu, which can be used to predict such interference in coal. The models are trained for Eu, Ba, Ba/Eu, and Ba interference with Eu. Under different user-defined parameters, different prediction models based on the corresponding model tree can be applied to Ba interference with Eu. We experimentally show the effectiveness of these different prediction models and find that, when the Ba/Eu value is less than 2950, the Ba-Eu interference prediction model is y = −0.18419411 + 0.00050737 × x, 0 < x < 2950. Further, when the Ba/Eu value is between 2950 and 189,523, the Ba-Eu interference prediction model of y = 0.293982186 + 0.00000181729975 × x, 2950 < x < 189, 523 yields the best result. Based on the optimal model, a threshold value of 363 is proposed; i.e., when the Ba/Eu value is less than 363, Ba interference with Eu can be neglected during Eu data interpretation. Comparison of this threshold value with a value proposed in earlier works reveals that the proposed prediction model better determines the threshold value for Ba interference with Eu.Minerals 2019, 9, 259 2 of 17 (INAA) [19][20][21], laser-ablation inductively-coupled plasma mass spectroscopy (La-ICP-MS) [22], sector-field inductively-coupled plasma mass spectroscopy ICP-MS [23], laser-induced break-down spectrometry [24][25][26], and quadrupole-based ICP-MS (ICP-Q-MS) [4,27]. Among these techniques, ICP-Q-MS has mostly been used for determination of REY concentrations in coal and CCPs. This is because of this method's ability to rapidly, precisely, and accurately measure REY content at very low detection limits in liquid and solid samples, with relatively simple spectra and a wide linearity range [14,[27][28][29]. However, in some cases, Eu concentrations in coal and CCPs cannot be accurately measured by the ICP-Q-MS. This difficulty is attributed to overlapping ion interference (such as those from M + , MO + , and/or MOH + ions) with Eu, which affects interpretation of the ICP-Q-MS spectra [30][31][32][33][34][35]. Because Ba concentrations in coal and CCPs are generally much higher than those of Eu [4,36], the most significant types of interference encountered for Eu in coal and CCPs are due to 135 Ba 16 O, 134 Ba 16 OH, 137 Ba 16 O, and/or 136 Ba 16 OH interfering with 151 Eu and/or 153 Eu. For example, the ratio of Ba vs. Eu for world coals is as high as~882 (with an average concentration of 150 µg/g Ba and 0.47 µg/g Eu) [36]. Therefore, as noted by Dai et al. [4], Eu content values in coal and CCPs determined via ICP-Q-MS should be treated with great caution. Recently, Yan et al. [27] described a reliable analytical method to avoid Ba-based ion interference with Eu in coal, CCPs, and sedimentary rocks during ICP-Q-MS procedures, which was based on AG50W-X8...

Progress in the Application of Machine Learning in Combustion Studies

“…Among the combustion theory studies, most of which are relevant to fuels, [30][31][32][33][34][35] part of which are targeted to study combustion phenomenon, [26][27][28][29] and only a few of studies concentrate on CFD simulation. [23][24][25] In industrial studies, ML has been used to study power plant boiler, [41][42][43][44][45] engine, [46][47][48][49][50][51][52][53][54] fuel [55][56][57][58] and other fields. [59][60][61][62][63][64] ML can be used to reduce mechanism, save PDF table memory and predict terms filtered by LES, in order to balance computation costs and accuracy of CFD combustion simulation.…”

“…Compared to theoretical studies, there are more industrial ones using ML algorithms. This section will introduce application of ML in industrial studies related to combustion, including power plant, [41][42][43][44][45] engine, [46][47][48][49][50][51][52][53][54] fuel [55][56][57][58] and other fields. [59][60][61][62][63][64] To reach the goal of efficient and clean combustion in electric generation, ML was used to classify coals, [41] monitor combustion process [42] and treat emissions [43][44][45] in power plants.…”

“…Biodiesel engine [46][47][48] HCCI combustion [49,50] and improving operational methods [51][52][53][54] are three branches of engine design where ML made contributions. Industrial studies about fuel, such as coal fuel [55,56] and predictions of cetane number (CN) [57] and octane number, [58] also utilized ML algorithms. Besides, ML was also applied to other studies, including gas turbine, [59] particulate matters, [60][61][62] organic Rankine cycle [63] and hydrogen array sensor detection.…”

“…The existence of Ba will interfere with the measuring of Eu, there is a threshold value for Ba/Eu beyond which the Eu concentration gotten by quadrupole-based inductivelycoupled plasma mass spectroscopy (ICP-Q-MS) is not reliable. Xu et al [56] implemented LR, regression tree to predict the threshold value of Ba/Eu. The established model predicted that the interference of Ba to the measurement of Eu could be neglected when Ba/Eu values were less than 363.…”

Coal Discrimination Analysis Using Tandem Laser-Induced Breakdown Spectroscopy and Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry

“…Boulyga et al 12 developed an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multielement analysis (chlorine, sulfur, and heavy metals) in coal samples. Xu and Li 13 proposed machine-learning-based prediction models for determination of the threshold value of Ba interference with Eu in coal and coal-combustion products by ICP-MS. Thompson et al 14 determined and quantified the mineralogical association of rare earth elements in coal fly ash using LA-ICP-MS and scanning electron microscopy−energy-dispersive Xray spectroscopy (SEM-EDS).…”