Hyphenated FT-IR-Attenuated Total Reflection and Electrochemical Impedance Spectroscopy Technique to Study the Water Uptake and Potential Stability of Polymeric Solid-Contact Ion-Selective Electrodes

2011 ◽  
Vol 83 (12) ◽  
pp. 4902-4908 ◽  
Author(s):  
Tom Lindfors ◽  
Lajos Höfler ◽  
Gyula Jágerszki ◽  
Róbert E. Gyurcsányi
2021 ◽  
Vol 188 (5) ◽  
Author(s):  
Elena Zdrachek ◽  
Eric Bakker

AbstractThe capacitance of the ion-to-electron transducer layer helps to maintain a high potential stability of solid-contact ion-selective electrodes (SC-ISEs), and its estimation is therefore an essential step of SC-ISE characterization. The established chronopotentiometric protocol used to evaluate the capacitance of the single-walled carbon nanotube transducer layer was revised in order to obtain more reliable and better reproducible values and also to allow capacitance to be measured before membrane deposition for electrode manufacturing quality control purposes. The capacitance values measured with the revised method increased linearly with the number of deposited carbon nanotube–based transducer layers and were also found to correlate linearly before and after ion-selective membrane deposition, with correlation slopes close to 1 for nitrate-selective electrodes, to 0.7 and to 0.5 for potassium- and calcium-selective electrodes. Graphical abstract


2010 ◽  
Vol 66 (a1) ◽  
pp. s294-s295
Author(s):  
Naomi E. Chayen ◽  
Lata Govada ◽  
K. L. Andrew Chan ◽  
Roslyn M. Bill ◽  
Sergei G. Kazarian

Membranes ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 128 ◽  
Author(s):  
Yan Lyu ◽  
Shiyu Gan ◽  
Yu Bao ◽  
Lijie Zhong ◽  
Jianan Xu ◽  
...  

Wearable sensors based on solid-contact ion-selective electrodes (SC-ISEs) are currently attracting intensive attention in monitoring human health conditions through real-time and non-invasive analysis of ions in biological fluids. SC-ISEs have gone through a revolution with improvements in potential stability and reproducibility. The introduction of new transducing materials, the understanding of theoretical potentiometric responses, and wearable applications greatly facilitate SC-ISEs. We review recent advances in SC-ISEs including the response mechanism (redox capacitance and electric-double-layer capacitance mechanisms) and crucial solid transducer materials (conducting polymers, carbon and other nanomaterials) and applications in wearable sensors. At the end of the review we illustrate the existing challenges and prospects for future SC-ISEs. We expect this review to provide readers with a general picture of SC-ISEs and appeal to further establishing protocols for evaluating SC-ISEs and accelerating commercial wearable sensors for clinical diagnosis and family practice.


2019 ◽  
Vol 73 (3) ◽  
pp. 329-336 ◽  
Author(s):  
Yongliang Liu ◽  
Hee-Jin Kim

In this investigation, we applied previously proposed simple algorithms to analyze the attenuated total reflection Fourier transform infrared (ATR FT-IR) spectra of cotton fibers during secondary cell wall (SCW) biosynthesis. The infrared crystallinity ( CIIR) and maturity ( MIR) indices were compared from developmental fibers representing two pairs of upland cotton near isogenic lines (NILs). One pair of NILs consisted of Texas Marker-1 (TM-1) and an immature fiber ( im) mutant that differ in fiber maturity. The other pair of NILs included MD52ne and MD90ne that show variations in fiber strength. The observations revealed significant difference in the MIR values between developmental TM-1 and im NILs grown at a field in crop year 2015, and also a significant difference in the CIIR values between these NILs grown at the same field in crop year 2011. These different patterns of CIIR and MIR values during fiber development for the two different crop years indicated the impact of genetics and crop year on the development of fiber maturity and crystallinity of the TM-1 and im fibers. Furthermore, the tendency of linking CIIR with MIR values suggested that the im fibers have more CIIR development than the TM-1 fibers when the fibers have the similar MIR values. In contrast, the NIL pair having variations in fiber strength showed insignificant differences in the patterns of CIIR and MIR as well as the relationship between CIIR and MIR values. The results suggested that CIIR and MIR indices from ATR FT-IR measurement could be used to facilitate the understanding of how fiber genetics and crop year affect fiber maturity and crystallinity during SCW biosynthesis.


2020 ◽  
pp. 000370282096971
Author(s):  
Nataša Radosavljević Stevanović ◽  
Milena Jovanović ◽  
Federico Marini ◽  
Slavica Ražić

Heroin is one of the most frequently seized drugs in Southeastern Europe. Due to the position in the Balkan route, the Republic of Serbia keeps important role in suppression of the trafficking of heroin for domestic and foreign illegal market. This research is aimed to provide a good scientific approach in the field of seized heroin analysis. Two different forms of heroin are present in the illegal market, mostly in mixtures with typical “cutting” agents: caffeine, paracetamol, and sugars. It was observed that the quantity of pure heroin in seized samples slightly increases from year to year. The aim of this study was to produce a reliable and fast procedure for classification of illicit heroin samples and determination of the concentration range of heroin in the samples. For that purpose, the attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) technique was used and combined with such chemometric methods as principal component analysis, cluster analysis, and partial least squares. Principal component analysis (PCA) as an unsupervised model was used for exploratory purposes to identify trends, similarities, and differences between samples by reducing the dimensionality of the data. The cluster classification of examined samples turned out to be extremely useful to evaluate the possibilities of the ATR FT-IR technique to classify the samples appropriately into the patterns, the constituted clusters. Additionally, partial least square was the suitable method for the purpose of determination of the heroin hydrochloride concentration range in examined samples. It is proved that the joined application of spectroscopy and chemometrics can be extremely convenient and useful for forensic and drugs control laboratories.


2010 ◽  
Vol 123-125 ◽  
pp. 851-854 ◽  
Author(s):  
Feng Xian Qiu ◽  
Dong Ya Yang ◽  
Qing Zhang ◽  
Guo Rong Cao

A novel azobenzene polyelectrolyte (ABAPE) was synthesized based on chromophore 4-(4’-nitrophenylazo) naphthol (NPAN), epoxychloropropane and α-methacrylic acid. The ABAPE was characterized by FT-IR and UV-vis spectroscopy. The aggregation behaviors of ABAPE were investigated based on different pH values by the UV-vis spectroscopy. The isomerization behavior of the ABAPE in DMAC solution was studied by 256 nm UV irradiation light. Attenuated total reflection (ATR) method was adopted and carried out the measurement of refractive index of the thin film. The thermo-optic coefficient (dn/dT) was -2.9228×10-4°C-1 and was bigger than inorganic materials such as silica glass, zinc silicate glass, borosilicate glass and the organic materials of polystyrene and PMMA. These results showed that the polyelectrolyte could be used to carry out optical storage and thermo-optic switch.


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