In-situ Diffusive Gradients in thin-films passive sampling coupled with ex-situ small-sized electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry as green and white method for the simultaneous determination of labile species of toxic elements in surface water

Simultaneous determination of Cd, Pb, Cu and Zn as total and labile fractions in soil using a small-sized electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometer after diffusive gradients in thin-film passive accumulation

“…Determinations were performed on a completely miniaturized SSETV-μCCP-OES set-up previously described. 47,52,53 The instrumentation consists of a μCCP (Babes-Bolyai University, Cluj-Napoca, Romania) with a Mo tip microelectrode (1.25 mm diameter, Goodfellow, Cambridge, UK) powered by an r.f. generator (10–30 W, 13.56 MHz, 15 × 17 × 24 cm 3 , Technical University, Cluj-Napoca, Romania) for plasma generation at 50–200 mL min −1 Ar in a quartz tube (5 mm i.d., 25 mm length, 160 nm cut-off, H. Baumbach & Co. Ltd., Ipswich, UK).…”

“…The basic assembly is presented in ref. 47 The capacitively coupled plasma operated at 15 W appears as a diffuse bluish discharge with a length of 8–10 mm and a width of 2–3 mm developed at the tip of the Mo microelectrode. 31 In the superficial luminescence zone, over the 0–1 mm viewing heights, appears the element excitation that allows the simultaneous multielemental emission spectra recording at 0.8 mm observation height through a lens, without fiber optics.…”

“…It has been shown that the μCCP operated at 15 W power has an excitation capability similar to other microplasma sources so that the emission spectrum consists of few resonant and non-resonant spectral lines with excitation energies ( E ex ) below 7 eV. 47 Due to the simple spectrum, a low-resolution microspectrometer such as Maya2000 Pro (FWHM 0.35 nm) could be used for episodic spectra recording. As a reference, the argon-hydrogen microplasma, studied by Karanassios' group and developed on a hybrid chip for elemental analysis of microsamples, operated at a lower power (4 W) compared to our plasma, has a length/width of 20/0.75 mm and allows the excitation of elements with E ex below 7 eV.…”

“…The working pH value of 4.0 ± 0.1 was selected based on a previous study showing that in the 4–7 pH range the accuracy of the ratio of the concentration determined using the DGT sampling to the analytical concentration of the uptake solution ( c DGT / c sol ) was in the range of 0.83–1.13 with a relative extended uncertainty of ±20% ( k = 2). 47 After assembling the DGT devices (filter membrane of polyethersulphone, the APA diffusive gel and the Chelex-100 binding gel) were immersed for 24 h in the uptake solution in triplicate (3 × 100 mL solution) avoiding touching the diffusion surface with the vessel walls. The solutions were gently stirred at 400 (× g).…”

“…The first study published by us highlights that the coupling between the DGT passive sampling with SSETV-μCCP-OES (DGT-SSETV-μCCP-OES) instrumentation is suitable for surface water monitoring related to the determination of elements with excitation energy below 7 eV. 47 Consequently, a highly sensitive method providing improved LODs was developed meeting the principles of GAC (AGREEprep) and WAC (Red/Green/Blue-RGB-12 concept) and providing high both green and white scores as a result of cost-effective SSETV-μCCP-OES instrumentation and in situ DGT passive sampling. 47 Increasing the technological maturity of the microplasma sources from the laboratory scale prototype to mature commercial instrumentation is a challenge and involves the development and validation of cost-effective and easy-to-run applications for the determination of priority hazardous elements and other traces providing analytical performance similar to the much more sophisticated laboratory equipment.…”