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This study reports a syringe injection pump for sample introduction for solution cathode glow discharge (SCGD) atomic emission spectroscopy (AES). The experimental conditions are optimized at 60 mA discharge current, 2.5 mm gap spacing, 2.0 mm distance from the glass capillary to cathode, 1.60 mL/min flow rate, and pH 1.0 based on the detection limits (DLs) obtained for Li, Cd, Cu, Ag, Mn, Pb, Cr, and Zn. The detection limits for Li, Cd, Cu, Ag, Mn, Pb, Cr, and Zn were 0.24, 12.26, 12.08, 1.09, 46.42, 25.81, 183.05, and 29.01 µg/L, respectively, significantly lower than using the traditional peristaltic pump. The detection limits decreased by 1.4, 1.8, 2.2, 5.0, 1.4, 1.4, 1.4, 1.6, and 2.2-fold for these elements. The flow rate and the solution consumed per unit time were significantly reduced using this design. The spectral detection revealed stable and practical operation of the system with relative standard deviations <0.85%. Water samples from Yangtze River, Baixi River, and Baiyun Reservoir are analyzed using the modified SCGD system and its evaluation is based upon comparison to inductively coupled plasma—optical emission spectroscopy (ICP-OES). The modified device operates at atmospheric pressure without inert gas and integrates a syringe injection pump and a compact spectrometer to optimize solution utility, analytical performance, and operation size for industrial and environmental monitoring applications. [ABSTRACT FROM AUTHOR]

A long-term sustainable tungsten cathode-solution anode glow discharge (SAGD) source for atomic emission spectrometry was developed for the determination of heavy metal elements. The tungsten cathode of this source was cooled by a compact refrigeration semiconductor, which is simple in design and able to operate at atmospheric pressure for long periods. When the equipment operates at its optimal conditions (75 mA discharge current, 2.0 mm discharge gap, 3.8 mL min−1 flow rate, and solution pH value of 2.0), the detection limits of Ag (338.24 nm), Cd (228.80 nm), Hg (253.66 nm), Pb (368.28 nm), Tl (337.52 nm), and Zn (213.79 nm) were explored, and the values were 0.030, 1.7, 7.2, 17, 0.24, and 25 μg L−1, respectively. The interference of coexisting ions in water, such as K+, Ca2+, Na+, Mg2+, and Li+, on the analytical performance of the solution anode glow discharge-atomic emission spectrometry (SAGD-AES) for Cd, Hg, Pb, and Zn were investigated. The results showed that coexisting metal ions' interferences are insignificant. The SAGD-AES system was successfully applied for analyzing water samples from the Yangtze River and Baixi River, and its accuracy and practicality were verified by comparison with inductively coupled plasma-optical emission spectrometry (ICP-OES) results. [ABSTRACT FROM AUTHOR]

Laser-induced breakdown spectroscopy was used for the analysis of the Chinese traditional medicine,Ligusticum wallichii. The laser energy and delay time were optimized to obtain best spectral quality. The limits of detection for lead and copper were 15.7 and 6.3 µg g−1, respectively. Multiple linear regression models between the laser-induced breakdown spectroscopy intensity and the mass fraction of lead and copper were constructed. Good agreement was observed between the actual concentrations and predicted values obtained by the models. These results demonstrate that the laser-induced breakdown spectroscopy coupled with multiple linear regression is suitable for the determination of heavy metals in Chinese traditional medicine. [ABSTRACT FROM PUBLISHER]

In this study, a refrigerating anode method was developed to improve solution cathode glow discharge-atomic emission spectrometry (SCGD-AES) for the determination of elements. Spectral characteristics of metal anodes at different temperatures were studied in the range from 10 to 30 °C. The spectral signals of metals were enhanced by reducing the metal anode temperature during the plasma discharge. Moreover, the method of the refrigerating anode improved the stability of spectral emission of metal elements. Compared with the unrefrigerated system under the same experimental conditions, the detection limits of Ag, Cd, Cu, Mn and Zn were 0.6, 9.1, 5.3, 8.7 and 16 μg L−1, respectively, which represented the improvements by 6.5, 3.5, 3.2, 3.9 and 3.1 times, respectively. The measurement results of Ag, Cd, Cu, Mn and Zn in a certified reference solution (BWB2446-2016) and an actual water sample from the Yangtze river by SCGD-AES with the refrigerating anode were in agreement with the reference values measured by ICP-OES. The water sample recovery from the Yangtze river ranged from 101.5 to 110.0%, suggesting that the measurement results exhibited high accuracy and reliability. All the results indicated that SCGD-AES coupled with a refrigerating anode could improve its analytical ability and provide an analytical method for in situ, real-time and on-line determination of metal elements in water samples. [ABSTRACT FROM AUTHOR]

Fig. 1. Schematic diagram of the modified SCGD-OES system: (a) Experimental setup; (b) auxiliary cathodes with different geometry. [Display omitted] • An improved SCGD micro-plasma source was developed for the quantitative determination of heavy metal elements. • Stainless steel (316L) was used as auxiliary cathode material, which greater durability and stability, and reduced DLs. • The detection limits for K, Na, Ni, Cd, Pb, Co and Hg were comparable to other solution cathode glow discharge systems. • The results from this study may provide a new direction for the design of glow discharge sources. An improved micro-plasma source for the quantitative analysis of heavy metal elements by solution cathode glow discharge-optical emission spectrometry (SCGD-OES) was developed. The glow-discharge plasma source was fabricated using a geometrically optimized stainless steel auxiliary cathode solution and a tungsten anode. Optimum discharge could be attained at reduced solution flow rates under the following operating conditions: pH 1.0 (HNO 3); a discharge current of 80 mA; a solution flow rate of 1.65 mL/min; and a discharge gap of 2.5 mm. The detection limits (DLs) of the improved micro-plasma source for K, Na, Ni, Cd, Co and Hg were 0.17, 0.06, 18, 10, 25 and 66 μg/L, respectively. The recoveries of metal elements from spiked samples of spring river, Yangtze River and reservoir water measured by SCGD-OES showed good agreement with those obtained using ICP-OES. The results from this study may provide a new direction for the design of glow discharge sources for the in situ determination of metal elements in complex water samples. [ABSTRACT FROM AUTHOR]

This study analyzed the effects of four microelemental fertilizers not only on growth rates and sclerotia formation of mycelia, but also the yields, amino acids contents and mineral elements of fruit body from artificially cultivated Morchella conica . Results showed that Fe·EDDHA had the strongest promoting effect on the mycelia growth, sclerotia formation and resulted in the highest yield, while CuSO 4 ·5H 2 O resulted in an adverse effect. Fe·EDDHA, Nutriagent and ZnSO 4 ·7H 2 O, respectively, increased the yields of morel's fruit bodies by 63.4%, 59.9% and 25.9% when compared with that of the control, but the yield of CuSO 4 ·5H 2 O group was reduced by 19.3%. The total amino acids contents of Fe·EDDHA, Nutriagent and ZnSO 4 ·7H 2 O groups were also significantly increased. Six microelements (Fe, Zn, B, Cu, Mn and Mo) and six heavy metals (Ni, As, Pb, Cr, Cd and Hg) were assayed and the highest Fe content was found in the Fe·EDDHA group, 7.10 times higher than that of the control group. [ABSTRACT FROM AUTHOR]