Three-Dimensional Printed Dual-Mode Chemical Vapor Generation Point Discharge Optical Emission Spectrometer for Field Speciation Analyses of Mercury and Inorganic Selenium

Abstract

Due to the large size and high energy consumption of instruments, field elemental speciation analysis is still challenging so far. In this work, a portable and compact system device (230 mm length × 38 mm width × 84 mm height) was fabricated by using three-dimensional (3D) printing technology for the field speciation analyses of mercury and inorganic selenium. The device comprises a cold vapor generator, photochemical vapor generator, and miniaturized point discharge optical emission spectrometer (μPD-OES). For mercury, inorganic mercury (IHg) was selectively reduced to Hg 0 by cold vapor generation, whereas the reductions of both IHg and methylmercury (MeHg) were obtained by photochemical vapor generation (PVG) in the presence of formic acid. For selenium, Se(IV) and total inorganic selenium were converted to their volatile species by PVG in the presence and the absence of nano-TiO 2 , respectively. The generated volatile species were consequently detected by μPD-OES. Limits of detection of MeHg, IHg, Se(IV), and Se(VI) were 0.1, 0.1, 5.2, and 3.5 μg L −1 , respectively. Precision expressed as the relative standard deviations (n = 11) were better than 4.5%. The accuracy and practicality of the proposed method were evaluated by the analyses of Certified Reference Materials (DORM-4, DOLT-5, and GBW(E)080395) and several environmental water samples with satisfactory recoveries (95−103%). This work confirms that 3D printing has great potential to fabricate a simple, miniaturized, easy-to-operate, and low gas and power consuming atomic spectrometer for field elemental speciation analysis.

Atomic Spectrometry Update: review of advances in elemental speciation

“…The final paper covered this section on Hg speciation in waters reports on the use of 3D printing to fabricate a field portable CV and photo-chemical vapour generator (PVG) μ-point discharge (PD)-OES instrument. 121 The system was compact with a total dimension of 230 × 38 × 84 and a complete description on the design and fabrication of the system is given in the paper and ESI. For Hg speciation, iHg was selectively reduced to Hg 0 with 0.001% (m/v) KBH 4 and 5% (v/v) HCl whereas the reduction of both iHg and MeHg was obtained by PVG in presence of formic acid and using a nano-TiO 2 coated quartz coil.…”

“…The use of 3D printing to fabricate a field portable CV and photo-chemical vapour generator (PVG) μ-point discharge (PD)-OES instrument. 121 The system was compact with total dimensions of 230 × 38 × 84 and a complete description of the design and fabrication of the system was given in the paper and ESI. Selenium speciation was evaluated by PVG-μPD-OES in the presence of 50 mmol L −1 of nitrate and with and without adding nano-TiO 2 NPs.…”

Speciation Analysis of Selenium Nanoparticles and Inorganic Selenium Species by Dual-Cloud Point Extraction and ICP-MS Determination

“…A three-dimensional printing prepared device was also reported for the field analysis of different inorganic Se species. 28 However, previous studies mainly focused on Se(IV) and Se(VI), and the determination of SeNPs was rarely reported. Though the direct speciation analysis of various Se species could be achieved by X-ray absorption near-edge structure spectroscopy, 29 the high detection limit and inaccessibility to the instrument hindered its wide applications.…”

“…Various methods such as ion-exchange chromatography (IEC), solid-phase extraction (SPE), , TiO 2 nanoparticle adsorption, , capillary electrophoresis, , and cloud point extraction (CPE) have been used to separate inorganic Se­(VI) and Se­(IV) in the aquatic system. A three-dimensional printing prepared device was also reported for the field analysis of different inorganic Se species . However, previous studies mainly focused on Se­(IV) and Se­(VI), and the determination of SeNPs was rarely reported.…”

Ultra-sensitive determination of mercury by atmospheric pressure glow discharge atomic emission spectrometry coupled with cold vapor generation

“…[19][20][21][22][23] Microplasma excitation sources include but are not limited to atmospheric pressure glow discharge (APGD), 20 electrolyte cathode glow discharge (ELCAD), 24,25 solution anode glow discharge (SAGD), 26 solution cathode glow discharge (SCGD), 27 dielectric barrier discharge (DBD) 28 and point discharge (PD). 29 Among them, APGD has attracted widespread attention in the eld of elemental analysis due to its compact structure, high stability and easy coupling. So far, APGD has been used in combination with various sampling systems and obtained satisfactory results.…”