增塑的PVC涂膜压电晶体传感器阵列用作香味传感系统

增塑的ＰＶＣ涂膜压电晶体传感器阵列用作香味传感系统曹忠，林辉概，王彬锋，王柯敏，陈泽忠，俞汝勤（湖南大学化学化工系，长沙，４１００８２）关键词阵列，压电晶体传感器，增塑的ＰＶＣ涂膜，香味传感系统吸附活性物质如类脂化合物等涂膜的压电晶体传感器（ＰＣＳ）...     

压电质量传感及其应用

本文介绍了压电质量传感即石英晶体微天平（ＱＣＭ）方法的原理及应用。深入探讨了非质量因素对晶振频率的影响、传感器响应讯号的测定方法。综述了压电免疫传感器的研制概况。提出了今后研究工作的方向。     

用于液相中检测的压电免疫传感器研究

利用聚乙烯亚胺法,将Ｃ２型葡萄菌肠毒素（ＳＥ）抗体固化在未抛光的压电晶体的金电极上,利用双调式振荡电路制作的振荡器,构建压电免疫传感器,其稳定性,特异性都较好。     

压电晶体传感器阵列测定装置及数据采集系统

研究了一种利用微机控制测量和采集压电晶体传感器阵列振荡频率的智能型仪器。介绍了其硬件及数据采集软件的功能，结构等。     

模式识别用于压电晶体传感器阵列识别可燃物质

用７个压电晶体组成传感器阵列,每个晶体上分别涂有不同种类的气相色谱固定液,通过测定各种可燃物质燃烧时放出的混合气体来识别所燃物质,在识别中分别应用了人工神经网络法（ＡＮＮ）和逐步判别分析法（ＳＤＡ）。讨论了解决神经网络开始训练时不收敛或产生麻痹现象的方法,提出了训练数据选取的新方法－训练集逐步扩展法,实验证明：人工神经网络对被测物质的识别准确率达１００％,高于逐步判别分析法（８３％）。     

压电晶体传感器阵列在补体系统免疫分析中的应用

将压电石英晶体阵列应用于补体系统免疫分析中,从而发展了一种新型的同步免疫分析方法,并对补体系统的四种成分（C4,C5,C1q,B因子）进行了分析测试。通过对不同条件（即抗体效价不同）下的多组分分析物进行同步检测,研究了补体系统免疫反应的特性和该传感器阵列的响应特性。差频信号的测量消除了粘度、温度和电导率的影响,同时对该传感器阵列晶体间的干扰进行了测试。该方法操作简单、准确、灵敏度较高。     

压电晶体传感器阵列判别分析小分子脂肪醇蒸气

选用８个不同材料涂层压电石英晶体组成传感器阵列，所获频移数据用逐步判别（ＳＤＡ）法解析，对小分子脂肪醇类与非醇类溶剂蒸气用二类判别法分析，找到由少于８个传感器组成阵列可达最佳判别能力，训练集回测正确率平均为８４．８％，预测集识别正确率平均为８７．３％。此外，该阵列用于识别酒、饮料，结果较佳。     

动力学—压电石英晶体传感器测定水中微量汞的研究

基于涂银压电石英晶体对ＣＮ＾－离子的灵敏响应，应用汞对六氰合铁酸钾与邻二氮杂菲反应的动力学催化作用，建立了动力学－ＰＱＣ传感器单面触液测定微量汞的新方法。研究了ＰＱＣ传感器对汞的响应机理，响应曲线，实验条件及共存离子干扰情况。     

丙肝压电免疫传感器的研制

研制了一种用于丙肝抗原检测的新型传感器——压电免疫传感器。采用AT切型、基频为10MHz伍英晶体作为换能器,先在晶体表面崮定巯基丙酸（MPA）,经过EDC和NHS活化后固定丙肝抗原（HCVAg）、最后检测不吲浓度的标准抗体溶液？分别研究了它的重复性和灵敏度,并通过临床验证了它的准确性此传感器其有灵敏度高、特异性好、不需标记、操作简单、能实时在线检测和重复使用等优点,能用于临床实验诊断、具有临床推广应用价值。     

甲胎蛋白压电免疫传感器的研究

以合成的甲基丙烯酸甲酯和甲基丙烯酸羟乙酯共聚作载体，在压电石英晶体表面涂覆共聚物涂层，经ＣＮＢｒ活化后固定ＡＦＰ抗体，研制成ＡＦＰ压电晶体免疫传感器，研究了固定化方法，载体量，抗原抗体结合时间，重现性选择性等实验条件和参数的影响，压电晶体的频移值与ＡＦＰ浓度在１００ｎｇ／ｍＬ～８００ｎｇ／ｍＬ的范围内有良好的线性关系，将此传感器初步用于人体血清样品的测定，并与放射免疫法对照，结果令人满意。     

A conductance sensor for dissolved sulphur dioxide using a series piezoelectric crystal device

A new piezoelectric crystal impedance sensor for the determination of sulphur dioxide in aqueous solution is presented. It is realized using a series piezoelectric crystal device which is constructed by connecting an AT-cut piezoelectric crystal to a probe in series. The probe is filled with an internal electrolyte solution that is separated from sample solutions by a gas-permeable membrane. The present sensor exhibits a favourable frequency response to 1 x 10(-7)-1 x 10(-3) M sulphur dioxide. The detection limit is 1 x 10(-8) M. The effects of the sensor preparation are considered. Dynamic range, reproducibility, response time and selectivity of the sensor are also discussed. The proposed sensor has been used successfully for lamp sulphur determinations in petroleum samples.     

A Rapid Method for Determination of Growth of Thiobacillus Ferrooxidans by Series Piezoelectric Quartz Crystal

ABSTRACT

A rapid and simple method for monitoring the growth of Thiobacillus ferrooxidans is put forward by using a series piezoelectric quartz crystal (SPQC). The SPQC was applied to continuously determine the variation of frequency shift during the culture of Thiobacillus ferrooxidans, with a conductive electrode as the probe. The frequency shift as a function of time agrees with a typical 'S - shape' model, a piezoelectric sensor responding well to the growth of Thiobacillus ferrooxidans. The fundamentals for determination of the bacterial growth activity using the SPQC is also described; the frequency shift is only dependent on the electrical conductivity of the solution and the dielectric constant.     

Behaviour of series piezoelectric sensor in electrolyte solution : Part II. Applications in titrimetry

The applications of a series piezoelectric sensor for end-point determination in frequencimetric titrations, including neutralization, precipitation, complexation and redox titrations, are reported. The method is based on the fact that a series piezoelectric sensor shows a sensitive and selective frequency response to changes in conductivity of solution and can be applied to sample solutions containing large amounts of unreacted foreign electrolytes.     

A new piezoelectric response model for population growth of bacteria

A piezoelectric response model on the population growth of microorganism is proposed. This model is based on a novel population growth model, which has a more obvious ecological meaning and the fact that the series piezoelectric quartz crystal (SPQC) sensor responses to conductivity changes of the medium during the growth of the microorganism. From the response model four parameters can be obtained including the maximum specific growth rate mu(m), saturated population size N(m), and two constants C and K(1). The influence of the parameters on the response curve is discussed in which the influences of mu(m) and N(m) are more obvious. With the proposed model the quantitative determination of bacteria may be more accurate than the frequency detection time (FDT) method. Then the growth of Escherichia coliform (E. coli) monitored with a SPQC sensor is compared with the simulated growth curve obtained by the proposed model and a good agreement is obtained.     

Electrodeless Piezoelectric Quartz Crystal Sensor for Determination of Total Urinary Reducing Sugar

A glucose-sensing system was developed in which an electrodeless piezoelectric quartz crystal was used to measure mass changes on the surface of a quartz plate during the reduction of Ag(NH₃)⁺₂ by glucose. A satisfactory correlation was obtained between the frequency shift and the glucose concentration in the range 1.0–25 mM, and the total reducing sugar in urine was determined. Treatment with 8 M nitric acid after each measurement was effective for cleaning the quartz surface, and the electrodeless piezoelectric quartz crystal sensor possessed excellent reproducibility and reusability during repeated use over 400 times. For the determination of total reducing sugar in urine (or blood), the present method can avoid the interferences occurring in a colorimetric method such as the color and turbidity of clinical specimens.     

A Novel Method for Mutagenicity Test of Carcinogen by using a Series Piezoelectric Quartz Crystal Bactrial Growth Sensor

ABSTRACT

A new method for mutagenicity testing of carcinogens is proposed in this paper. Mutagenic activity is examined through monitoring of the growth situation of Salmonella typhimurium TA98 strain with a series piezoelectric quartz crystal (SPQC) sensor. This method needs no immobilization and preincubation of microorganism, and is simple and rapid. It can be applied to detect mutagen directly. When it was used to study the mutagenicity of dimethyl sulfate, the test time was 4 h at 37°C. There was a good linear relationship between frequency shift and the dose of mutagen in the range 2.5-20 μg/mL and the regression equation was ∠F = 53.82 + 3.81C. Some experimental conditions are also discussed in detail.     

A New Sensor Method for Studying the Effect of Gentamicin and Cefotaxime Combination Against Escherichia coli

Abstract

A new sensor method based on a multi-channel series piezoelectric quartz crystal (MSPQC) was proposed for studying the effect of gentamicin and cefotaxime combination against Escherichia coli ATCC 25922. The frequency curves under different combination regimens were obtained and compared with each other. When antibiotic had an inhibitory effect to the growth of bacteria, frequency detection time (FDT) would be prolonged. The FDT was used to assess the effect of an antibiotic combination. By using the proposed method, simultaneous administration, different order, and time interval of nonsimultaneous administration were investigated in detail. The MSPQC method can provide the process information in real time. It is simple, rapid, and easy to perform.     

Multi‐Channel Piezoelectric Quartz Crystal Sensor with Principal Component Analysis and Back‐Propagation Neural Network for Organic Pollutants from Petrochemical Plants

A multi‐channel piezoelectric quartz crystal gas sensor comprising arrays coated with various organic materials and a home‐made computer interface for data processing were prepared and employed to detect six kinds of common organic pollutants from petrochemical plants including benzene, styrene, chloroform, octane, hexene and hexyne. The principal component analysis (PCA) method was employed to select six kinds of appropriate coating materials for these organic pollutants from 22 adsorbents onto piezoelectric crystals. After performing a PCA assay, six representative coating materials, namely Polyisobutylene, Poly(dimethylsiloxane) (SE30), 4‐tert‐Butylcalix[6]arene, Cholesteryl chloroformate, C60‐Polyphenyl acetylene (C60‐PPA) and Ag(I)/cryptand‐2,2/Ethylene diamine/NH₃/Polyvinyl chloride were selected. Moreover, effects of coating load of adsorbents and concentration of pollutants were also investigated. Three kinds of recognition techniques including 2D PCA score map, radar plot and back‐propagation neural network (BPN) were employed for qualitative analysis of these organic pollutants, and a quantitative analysis method could be established by creating calibration curves for each organic pollutant. This homemade multi‐channel piezoelectric quartz crystal gas sensor showed a good detection limit of 0.068‐1.127 mg/L for these organic pollutants. The multi‐channel piezoelectric gas sensor exhibited good reproducibility with a relative standard deviation (RSD) of 1.1‐9.6%. Furthermore, this multi‐channel piezoelectric crystal detection system with BPN recognition technique was also utilized to successfully distinguish and identify each component of the mixture of organic gas samples. Multivariate linear regression (MLR) analysis was employed to quantitatively compute the concentration of species in the organic mixtures.     

A Coated Piezoelectric Crystal Sensor for the Determination of 2, 4-Toluene Diisocyanate in Air

Abstract

2, 4-toluene diisocyanate (TDI) in air was detected and determined by a piezoelectric quartz crystal sensor coated with tetrakis(hydroxyethyl)ethylenediamine (THEED)/dithizone(diphenylthiocarbazone) solution (l:3v/v in acetone). The response curve is linear over the concentration range 3–24 ppb of TDI. The sensor can be used for more than 2 months without loss in sensitivity and presented good reversibility and reproducibility. Of the different possible interferents tested, only SO₂ caused a frequency change.     

Detection of Sulfur Dioxide Using a Piezoelectric Quartz Crystal Microbalance

Abstract

Sulfur dioxide was detected and determined in air by a piezoelectric quartz crystal sensor coated with 4-aminoantipyrine 1-hydroxyetil-2-heptadecenyl imidazol (amine 220) solution (1:1 v/v in chloroform). The analytical response curve is linear over the concentration range from 0.70 to 5.0 ppm of SO₂. Good linearities (r = 0.9990, 0.9995 and 0.9968) and sensitivities (18.0, 33.4 and 50.7 Hz/ppm) were found, respectively for exposure times of 30, 60 and 90 seconds. The sensor can be used for more than six months without loss in sensitivity and presented good reversibility and reproducibility. Among some possible interferents tested, only nitrogen dioxide and moisture caused major frequency changes.