Direct determination of lanthanides in environmental samples using ultrasonic nebulization and ICP OES

Abstract

Baixas concentrações dos catorze elementos de ocorrência natural da série lantanídeos foram diretamente determinadas por espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES). Avaliaram-se interferências espectrais e linhas espectrais mais adequadas foram selecionadas. Os desempenhos da nebulização pneumática e ultra-sônica foram comparados com respeito aos limites de detecção, para ambas as posições de observação do plasma, radial e axial. A influência da potência de radiofrequência sobre a precisão e exatidão foi também investigada para os dois tipos de nebulizadores. O método foi aplicado à determinação dos lantanídeos em amostras ambientais (sedimentos, cinza de carvão e água fluvial). Este trabalho demonstrou que é possível a determinação direta de baixas concentrações (i.e. ng g -1 e ng L -1 ) dos lantanídeos de ocorrência natural por ICP OES.Low concentrations of the fourteen naturally occurring lanthanides were directly determined by inductively coupled plasma optical emission spectrometry (ICP OES). Spectral interferences were evaluated and the most appropriate spectral lines selected. Pneumatic and ultrasonic nebulization performances were compared with respect to limits of detection for both radial and axial viewed plasma. The influence of plasma applied power on precision and accuracy was studied for both nebulizers. The developed method was applied to lanthanides determination in environmental samples (sediments, coal fly ash and river water). This work demonstrates that the use of ultrasonic nebulization combined with axially viewed plasma allowed direct determination of low concentrations (at ng g -1 and ng L -1 levels) of all naturally occurring lanthanides by ICP OES. Keywords: lanthanides, ICP OES, ultrasonic nebulization, pneumatic nebulization, environmental samples IntroductionThe elements of the lanthanides series, ranging from lanthanum to lutetium comprises fithteen homologous trivalent metals, of which fourteen commonly occur in nature. Promethium does not occur naturally. Lanthanides mobilization from their natural sources has increased in the last decades. Because of their diversified physical and chemical properties, the lanthanides elements have been widely used in a number of fields (e.g., in microelectronics and optics, in material science or in nuclear reactors, in biomolecular research or in medical diagnostics).1-3 The lanthanides are also often used in fertilizers 4 or as feeding markers in nutritional and agronomic studies. [4][5][6] These elements have also been used as fingerprint markers for cement and concrete 7 and in geological 8 or palenteology studies. 9Uses and applications of lanthanides are still increasing and so are the associated emissions to the environment. In recent years, lanthanides-rich fertilizers have being widely used in China to enhance yield and improve crop quality. It is reported that application of these fertilizers not only increases the yield but also brings many visual benefits to plants including darker green foliage, enha...

XoxF Acts as the Predominant Methanol Dehydrogenase in the Type I Methanotroph Methylomicrobium buryatense

“…Many methanotrophs, including M. buryatense isolates, have been isolated from sediment samples. In freshwater sediment samples collected from standard sediment collections, lanthanum concentrations have been reported to be around 42 g lanthanum per g sediment (38). Lanthanum is largely insoluble under most environmental conditions; however, the sedimentary lanthanum concentrations found are approximately 300 times the concentration of lanthanum shown to inhibit P mxaF transcription (0.14 g lanthanum per g cultivation medium) (Fig.…”

“…The decrease of 3 to 4 orders of magnitude in mxa expression by lanthanides in the presence of calcium suggests that XoxF may be the dominant MDH in environmental settings, where lanthanides are relatively abundant (26,27,38). To test this hypothesis in a laboratory setting, an xylE reporter gene was fused to the promoter of mxaF to create an M. buryatense 5GB1C strain with P mxaF -xylE integrated into the chromosome at a region known to be transcriptionally silent (4).…”

Integrated Synthesis of Zeolites Using Coal Fly Ash: Element Distribution in the Products, Washing Waters and Effluent

“…Next, the samples were quantitatively transferred to polypropylene vials, which were topped up to 50 mL with deionized water. 43,51 For ICP-MS analysis the samples were diluted with a 5% HNO 3 solution (v/v) as needed. Method accuracy was assessed using CRMs and indicated absolute errors (in three determinations) lower than 10% (for elements with certified values) and recoveries within the acceptable measurement range, demonstrating that the above method can be extended to samples with similar frameworks (see Supplementary Information section for more details of these results).…”

Multivariate optimization for cloud point extraction and determination of lanthanides

“…Argon from White Martins/Praxair (Brazil) was used as plasma gas and auxiliary gas, whereas nitrogen with a purity of 99.996% (from White Martins/Praxair) was used as the purging gas. 27 A high efficiency nebulizer ESI APEX-Q (ESI, Omaha, NE) was used for sample introduction into the ICP. The sample was introduced through a PFA microconcentric nebulizer fitted to a cyclonic spray chamber heated at 140 C. The aerosol was then transported to a Peltier-cooled multipass condenser where the temperature was À3 C. The instrumental conditions used are summarized in Table 1.…”