Purpose: The purpose of this paper is to present the properties of thick-film resistors made of novel pastes prepared from glass and graphite. Design/methodology/approach: Graphite-based resistors were made of thick-film pastes with different graphite-to-glass mass fraction were prepared and examined. Sheet resistance, temperature coefficient of resistance, impact of humidity and short-term overload were investigated. The properties of the layers fired in atmospheres of air at 550°C and nitrogen at 875°C were compared. Findings: Graphite-based resistors with various graphite-to-glass ratios made possible to obtain a wide range of sheet resistance from single O/square to few kO/square. These values were dependent on firing atmosphere, paste composition and the number of screen-printed layers. The samples made of paste with 1:1 graphite-to-glass ratio exhibited the temperature coefficient of resistance of about −1,000 ppm/°C, almost independently on the firing atmosphere and presence of a top coating. The resistors fired in the air after coating with overglaze, exhibited significantly lower sheet resistance, reduced impact of humidity and improved power capabilities. Originality/value: In this paper, graphite-based resistors for applications in typical high-temperature cermet thick-film circuits were presented, whereas typical graphite-based resistors were fabricated in polymer thick-film technology. Owing to very low cost of the graphite, the material is suitable for low-power passive circuits, where components are not subjected into high temperature, above the typical temperature of operation of standard electronic components.

A novel portable excitation microsource for optical emission spectrometry (OES) based on atmospheric pressure glow discharge with a liquid drop anode (LDA-APGD), generated in a ceramic microchip (mch), was developed. This excitation microsource uses low temperature cofired ceramic (LTCC) microchips to provide electrical contact and fabricate a hollow to hold a microsample solution. Optimization of this new excitation source was performed for the quantification of Hg in liquid samples and discussed. Optimal parameters for Hg determination were: polarized liquid drop – anode, discharge current – 80 mA, solution drop volume – 15 μL, He flow rate – 300 mL min⁻¹, chip hollow dimensions: diameter 3.0 mm and depth 0.6 mm, HNO₃ concentration – 0.10 mol L⁻¹. The addition of low molecular weight organic compounds (LMWOCs) to the solution was also tested. The linearity range for mch-LDA-APGD was up to 30 mg L⁻¹, and the limit of detection (LOD) of Hg was 47 μg L⁻¹. Precision of this method was within 0.65–8.7% (as the relative standard deviation of repeated measurements). Recoveries obtained for tap water samples spiked with Hg(II) ions at 100, 200, and 300 μg L⁻¹ were within the range of 96–122%.

In this article, we present a development of atmospheric pressure plasma jets (APPJs) for modification of liquid solutions. APPJs were fabricated in low temperature cofired ceramics (LTCC) technology. During the measurements, plasma jets worked under various flowing gases, which can be used to produce plasma activated water. In addition, owing to the plasma treatment, it was possible to decrease the time of a synthesis of gold nanoparticles (AuNPs) without the use of additional hazardous reagents. The mechanism of gold nanoparticles formation in cold nitrogen plasma is also presented.

Purpose: The purpose of this paper is to present a study on miniaturized instruments for analytical chemistry with a microplasma as the excitation source. Design/methodology/approach: The atmospheric pressure glow microdischarge could be ignited inside a ceramic structure between a solid anode and a liquid cathode. As a result of the cathode sputtering of the solution, it was possible to determine its chemical composition by analyzing the emission spectra of the discharge. Cathodes with microfluidic channels and two types of anodes were constructed. Both types were tested through experimentation. Impact of the electrodes geometry on the discharge was established. A cathode aperture of various sizes and anodes made from different materials were used. Findings: The spectroscopic properties of the discharge and its usefulness in the analysis depended on the ceramic structure. The surface area of the cathode aperture and the flow rate of the solution influence on the detection limits (DLs) of Zn and Cd. Originality/value: Constructed ceramic structures were able to excite elements and their laboratory-size systems. During the experiments, Zn and Cd were detected with DLs 0.024 and 0.053 mg/L, respectively.

In this paper we present miniature Atmospheric Pressure Glow Micro Discharge plasma generator device with evaporating, liquid cathode. The device is fabricated in the Low Temperature Cofired Ceramics. This material offers low-cost fabrication and is temperature resistant. The device can be used to qualitative and quantitative investigation of some elements and molecules in liquid samples. In our investigation we focus on the determination of Cu concentration in copper ore concentrate. The strong emission coming from Cu atomic lines were monitored. We obtain emission from copper at four wavelengths. It enables detection of the element with accuracy depending on wavelength, but proportional to amount of copper in the sample. In the article performance of the device is compared with typical plasma systems.

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