State of the art in the validation of screening methods for the control of antibiotic residues: is there a need for further development?

ABSTRACT

Screening methods are used as a first-line approach to detect the presence of antibiotic residues in food of animal origin. The validation process guarantees that the method is fit-for-purpose, suited to regulatory requirements, and provides evidence of its performance. This article is focused on intra-laboratory validation. The first step in validation is characterisation of performance, and the second step is the validation itself with regard to pre-established criteria. The validation approaches can be absolute (a single method) or relative (comparison of methods), overall (combination of several characteristics in one) or criterion-by-criterion. Various approaches to validation, in the form of regulations, guidelines or standards, are presented and discussed to draw conclusions on their potential application for different residue screening methods, and to determine whether or not they reach the same conclusions. The approach by comparison of methods is not suitable for screening methods for antibiotic residues. The overall approaches, such as probability of detection (POD) and accuracy profile, are increasingly used in other fields of application. They may be of interest for screening methods for antibiotic residues. Finally, the criterion-by-criterion approach (Decision 2002/657/EC and of European guideline for the validation of screening methods), usually applied to the screening methods for antibiotic residues, introduced a major characteristic and an improvement in the validation, i.e. the detection capability (CCβ).

In conclusion, screening methods are constantly evolving, thanks to the development of new biosensors or liquid chromatography coupled to tandem-mass spectrometry (LC-MS/MS) methods. There have been clear changes in validation approaches these last 20 years. Continued progress is required and perspectives for future development of guidelines, regulations and standards for validation are presented here.     

Improving the DMFC performance with Ketjen Black EC 300J as the additive in the cathode catalyst layer

Ketjen Black EC 300J with an extremely high mesoporous area and electrical conductivity, was used as an additive in the cathode catalyst layer to improve the DMFC (direct methanol fuel cell) performance. Ketjen Black EC 300J and the catalyst ink were characterized by TEM. The cathode catalyst layers were characterized by SEM, in situ cyclic voltammetry and I–V curve measurements. Ketjen Black EC 300J additive increased the dispersion extent of Pt black particles and improved the Pt utilization. In addition, the pore size and porosity was increased when Ketjen Black EC 300J was added into the cathode catalyst layer. The cathode catalyst layer with Ketjen Black EC 300J additive showed a greater single cell performance than the cathode catalyst layer without any additive, especially in the air-breathing mode. These results suggested that the performance improvement was attributed to the increased Pt utilization, oxygen diffusion and water removal capability when Ketjen Black EC 300J was added into the cathode catalyst layer.     

20%三磷·哒乳油对柑桔红蜘蛛毒力测定及田间药效试验

室内毒力测定结果表明,20％三磷·哒乳油对柑桔红蜘蛛有明显的增效作用,其共毒系数为178.6。1999年经江西进贤和湖南洪江两地田间试验表明,三磷·哒乳油对柑桔红蜘蛛有较好的防治效果,75～100mg／kg处理药后1～3天的防效为90.O％～98.0％,药后7天为82.7％～96.2％,药后15天为56.2％～92.3％,药后25天为51.6％～91.0％。     

无线数据业务的市场发展分析

无线数据业务迅猛发展,其应用前景非常广阔。本文分析了国内无线数据业务现状,提出了未来移动数据业务的应用情况,并对电子商务模式和无线终端发展趋势进行了探讨。最后示出了消费者对各种增值服务的态度。     

对欧盟压力设备指令97/23/EC中危险品分类的诠释

欧盟97/23/EC压力设备指令中压力设备的分类与介质危险性有关.按照97/23/EC,将爆炸性、易燃性、氧化性与毒性介质列为危险介质,本文根据97/23/EC以及67/548EEC等欧盟指令对压力设备中危险介质的分类及其定义,判据进行了阐明,对我国压力容器和压力管道中危险介质的划分及分类将有很大的参考价值.     

基于EC2R模型的决策单元规模收益的判定

详细阐述了EC^2R模型中判定决策单元规模收益的理论．首先给出了决策单元的概念,然后推广了规模收益的适用范围,最后提出了决策单元规模收益的判定,并结合一个具体实例进行了说明．与以前的判定方法相比,文中的方法计算量较小,在得出决策单元相对效率的同时,就可以判断决策单元的规模收益情况,具有较强的适用性、操作性和应用性．     

欧盟电动汽车技术法规研究

从电动汽车的电气安全、电磁兼容、刹车要求、乘员保护等方面,围绕EC指令和ECE法规的修订工作,全面阐述了欧盟关于电动汽车的技术要求,总结了相关技术法规的修订和起草现状,给出了欧盟电动汽车相关技术立法的阶段性发展趋势。     

浅析中国B2C电子商务中的信用风险及对策

信用风险已经成为电子商务发展的瓶颈之一.商家为了保证电子商务的发展,在借鉴国外电子商务模式的基础上,创造了中国电子商务的4种信用模式,在一定程度上促进了电子商务的发展,但是存在着认证速度慢、信用借助于第三方银行或商家担保的缺陷.为了弥补此类缺陷,国家出台了相关法律,制定了网络公证计划,从法律和技术两个层面为电子商务发展提供了国家信用保证.