Piezoelectric enzyme sensor with improved temperature characteristics for determining urea in urine

Shen, Dazhong; Kang, Qi; Wang, Xingyong

doi:10.1007/bf01242332

Cited by 2 publications

(2 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the frequency shift varies linearly with (ρη) 1/2 as predicted by the Gordon-Kanazawa's equation 26 , the slope does not agree with the one obtained by this equation. The slope is larger than that of the normal PQC by a factor of about 1.4, which agrees with the 1.5 factor obtained by Dazhong et al 16 for other ESPC system. Since temperature greatly affects the viscosity, it is important to evaluate this effect over the baseline.…”

Section: Resultssupporting

confidence: 91%

See 1 more Smart Citation

Improving the sensitivity of electrode-separated piezoelectric quartz crystal sensor for copper(II) ions by immobilization of the N-2-aminoethyl-3-aminopropylsilane group

Jesus¹,

Neves²,

Lago³

2001

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Um sensor a cristal piezelétrico de quartzo com eletrodos separados e superfície quimicamente modificada foi proposto. A silanização com N-2-aminoetil-3-aminopropiltrimetoxisilano permitiu a imobilização do grupo N-2-aminoetil-3-aminopropilsilano sobre a superfície de um cristal de quartzo de 3,5 MHz. Uma cela em fluxo foi fabricada em poli(metacrilato de metila) com dois eletrodos de latão. Nesta cela, a solução entra em contato somente com um lado do cristal e o eletrodo é recoberto com um filme de poliéster, prevenindo assim a corrosão do eletrodo. Esta inovação reduz o custo da cela e proporciona o desacoplamento DC. O cristal modificado mostrouse mais sensível a íons cobre (II) do que a magnésio(II), níquel(II), zinco(II) e cobalto(II). Para injeções de 100 µL de amostra, o limite de detecção para cobre(II) foi de 6 µmol L -1 que é um resultado significativo comparado com aqueles obtidos com cristal não modificado.An electrode-separated piezoelectric quartz crystal sensor with a chemically modified surface was proposed. The modification was carried out by a silanization procedure with N-2-aminoethyl-3-aminopropyltrimethoxysilane, yielding the immobilised N-2-aminoethyl-3-aminopropylsilane group over the surface of a 3.5 MHz piezoelectric quartz crystal. A flow cell was manufactured with poly(methyl methacrylate) and brass, instead of noble metals, for the electrodes. In this cell, the solution touches only one side of the crystal and the related electrode is coated with a polyester film, which prevents corrosion and does not disturb the oscillation process. This innovation reduces the cost of the cell and renders an electronics non DC-coupled to the solution. The modified crystal proved to be more sensitive to copper(II) ions than magnesium(II), nickel(II), zinc(II), and cobalt(II). For 100µL sample injections, the limit of detection for copper(II) was 6 µmol L -1 , which is an impressive result when compared with that for an unmodified crystal.

show abstract

Section: Resultssupporting

confidence: 91%

“…Other works dealing with applications and characterization of the ESPC have been published [3][4][5][6][7] . Although the oscillation frequency is changed by all the above properties, some approaches use variations of the bulk of the liquid [3][4][5][6] , mass deposition on the crystal surface [10][11][12][13][14][15][16] , or both 17 .…”

Section: Introductionmentioning

confidence: 99%