Direct and Sensitive Determination of Antimony in Water by Hydrogen-Doped Solution Anode Glow Discharge-Optical Emission Spectrometry Without Hydride Generation

Abstract

In the present work, a novel, simple, and sensitive method for the direct determination of trace Sb in water samples was developed based on hydrogen-doped solution anode glow discharge-optical emission spectrometry (SAGD-OES). It was found that the vapor generation and excitation of Sb occurred simultaneously in the SAGD, contributing to the significant improvement in the sensitivity of Sb as compared with normal pure He-operated SAGD or solution cathode glow discharge. Besides, the proposed hydrogen-doped SAGD-OES could be operated even at pH = 14, which could reduce the interference of coexisting ions as many metal ions could be precipitated and removed. Our results demonstrated that the proposed method offered good tolerance to the interferences of Li, Na, Ca, Mg, Fe, Ni, Mn, and Zn ions even at a concentration of 50 mg L −1 . Under optimized conditions, the limit of detection of Sb was 0.85 μg L −1 , which was comparable to that of microplasma sources coupled with conventional hydride generation. The linearity of the Sb calibration curve reached R 2 > 0.999 in the 5−5000 μg L −1 range. Finally, the accuracy of the proposed method was validated by the determination of certified reference materials [GSB 07-1376[GSB 07- -2001 (1) and ( 2))] and real water samples. The proposed low-power (6 W), green, sensitive, rapid, and robust method provides a promising approach for on-site trace Sb analysis and may also be extended to other elements.

Highly sensitive determination of arsenic in water samples by hydrogen-doped solution anode glow discharge-optical emission spectrometry

“…In our previous study, He was employed because of its high excitation capacity and ease of maintaining the SAGD plasma. 38 However, it is very expensive, and consequently it would be more attractive if we can measure As with Ar. Thus, the analytical performance of SAGD-OES with Ar as the discharge gas is investigated and compared with that with He.…”

“…To maintain the SAGD plasma, the structure of the SAGD cell is slightly modified from that in a previous study. 38 In a quartz tube (i.d., 25 mm; o.d., 27 mm and height, 70 mm), the top and bottom part are used for the cathode electrode and solution (sample) introduction, respectively. The supporting gas (mixture of Ar and H 2 ) was introduced into the quartz SAGD cell from a hole close to the quartz window to minimize the effect of moisture or any contamination on the window.…”

“…In our previous work, the efficient vapor generation and excitation of Sb was realized simultaneously by hydrogen-doped SAGD-OES, and it enables direct sensitive Sb analysis (without HG for sample introduction) in water samples with an LOD as low as 0.85 μg L −1 . 38 Therefore, it's reasonable to expect that hydrogen-doped SAGD may also provide a simple and sensitive method for direct As analysis in water samples.…”

“…Recently, micro-plasma sources have received increasing attention as they favor the development of more compact and portable instruments because of their small size, reduced gas and power consumption, and relatively low manufacturing cost. [20][21][22] Various micro-plasma sources, including solution cathode glow discharge (SCGD), [23][24][25] low-power capacitively coupled plasma (CCP), 26 dielectric barrier discharge (DBD), [26][27][28] point discharge (PD), 29,30 atmospheric pressure glow discharge (APGD), 13,[31][32][33][34] and solution anode glow discharge (SAGD) [35][36][37][38][39] have been developed for elemental determination (including that of As). Sensitive As determination can be achieved by combining hydride generation (HG) with micro-plasma sources, such as DBD, 27 SCGD, 40 and CCP, 26 where the detection limit (LOD) of As was 4.8, 4.2, and 0.2 mg L −1 , respectively.…”

Microdischarge in Flame as a Source-in-Source for Boosted Excitation of Optical Emission of Chromium

“…In recent years, microplasma-based miniaturized atomic spectrometers have attracted extensive concerns, especially the optical emission devices for metal element determination in field analysis applications. Owing to the advantages of a small size, low power consumption, and atmospheric pressure operation, various types of microplasmas have been constructed, including but not limited to atmospheric pressure glow discharge, − solution cathode glow discharge, , liquid anode glow discharge, − dielectric barrier discharge (DBD), − and point discharge (PD). − However, there are few reports for these excitation sources used for Cr determination. Among various microplasmas, PD may be the simplest one, because of the direct discharge commonly between two electrodes with one- or two-needle design.…”