A Melamine Field Sensor for Surety Control of Dairy Products

描述(申请人提供)：提出了一种廉价的一次性传感元件，可以检测乳制品中的三聚氰胺污染，并作为现场质量控制监控器。该传感器与电池供电的读取器相结合，将在2008年中国牛奶污染事件后提供市场所需的特定保证控制。该传感器基于表面增强拉曼光谱(SERS)，它允许精确检测强烈吸附到粗糙的SERS传感器上的化学物质，如三聚氰胺，进入ppb范围。SERS传感器是气相沉积的银膜，随后进行电化学粗化，制造成本低廉，可以用于牛奶等复杂基质中。由于传感器被调谐到感兴趣的分析物，所以来自浓度更高的化学物质的干扰是有限的。因此，牛奶成分的广泛分离是不必要的。这将表明，在测量之前，简单的一步蛋白质变性是唯一需要的前处理。在本节目中，将介绍一种适用于现场应用的简单方案，即提取牛奶样品、快速变性、水相取样和在5分钟或更短的时间内进行SERS测量。SERS传感器将使用电池供电的拉曼仪器读取，该仪器带有带键的采样室，确保SERS传感元件自动对准系统。紧凑的系统将是完全自动化的，并将光谱库与偏最小二乘分析结合在一起。将向现场技术人员报告三聚氰胺的鉴定和定量。一个读取器可用于多个现场评估。便携式检测将补充更复杂的实验室方法，并将防止受污染的牛奶到达消费者手中。这项技术的核心概念已经得到开发和演示。文献结果表明，SERS检测三聚氰胺和EIC实验室对全脂牛奶中三聚氰胺的检测有初步证据。第一阶段计划旨在定义、优化和量化1)在这一应用中使用的SERS传感器和2)蛋白质变性步骤。后者将在水相中优化三聚氰胺的产量，而前者将在耐用性、灵敏度和重复性方面进行优化。第一阶段计划将展示检测全脂牛奶、2%牛奶、脱脂牛奶和重质奶油中三聚氰胺的检测限、信号线性和精确度。在第一阶段计划中，将证明牛奶基质中的变化不会影响三聚氰胺的SERS测量精度。 公共卫生相关性：相关性：拟议的便携式SERS读取器带有可用于监测牛奶中三聚氰胺污染的一次性传感元件，为FDA和其他监管机构提供了一种快速、可重复的检测方法，可在关键的制造设施使用，而无需等待实验室分析。传感器将允许以较低的成本进行更大规模的数据采样，并可以扩展到其他潜在污染物。

DESCRIPTION (provided by applicant): An inexpensive disposable sensing element that can detect melamine contamination in dairy products and serve as an on-site quality control monitor is proposed. This sensor, coupled to a battery operated reader, will serve a specific surety control needed in the marketplace after the China milk contamination of 2008. The sensor is based on Surface-Enhanced Raman Spectroscopy (SERS), which allows precise detection of chemicals that adsorb strongly to roughened SERS sensors, like melamine, into the ppb range. The SERS sensors, vapor deposited silver films with subsequent electrochemical roughening, are inexpensive to make and can be used in complex matrices like milk. As the sensors are tuned to the analytes of interest, interferences from more concentrated chemicals is limited. Therefore, an extensive separation of milk components is not required. It will be shown that a simple one-step protein denaturation is the only preprocessing required before measurement. In this program, a simple protocol suitable for on-site applications wherein a milk sample is drawn, rapidly denatured, the aqueous phase sampled and the SERS measurement made in 5 minutes or less will be presented. The SERS sensors will be read using a battery operated Raman instrument with keyed sampling chamber that ensures the SERS sensing elements are automatically aligned into the system. The compact system would be fully automated and incorporate a spectral library with partial least squares analysis. Identification and quantification of melamine would be reported to the field technician. A single reader can be used for multiple field site evaluations. The portable test would complement more sophisticated laboratory methods and would prevent tainted milk from reaching the consumer. The core concepts of this technology have been developed and demonstrated. Literature results show SERS detection of melamine and EIC Laboratories has preliminary evidence for detection of melamine in whole milk. The Phase I program is designed to define optimize and quantify 1) the SERS sensors to be utilized in this application and 2) the protein denaturing step. The latter will be optimized for melamine yield in the aqueous phase while the former will be optimized for durability, sensitivity and reproducibility. The Phase I program will demonstrate detection limits, signal linearity and precision for the detection of melamine in whole milk, 2% milk, fat-free milk and heavy cream. In the Phase I program, it will be demonstrated that variances in the milk matrix will not affect the SERS measurement precision for melamine. PUBLIC HEALTH RELEVANCE: Relevance: The proposed portable SERS reader with disposable sensing elements that can be used to monitor melamine contamination of milk gives the FDA and other regulatory agencies a rapid reproducible detection method to use at key manufacturing facilities without waiting for laboratory analyses. The sensors will allow larger data samplings at lower costs and can be extended to other potential contaminants.