Detection and Quantification of Chloramphenicol in Milk and Honey Using Molecularly Imprinted Polymers: Canadian Penny‐Based SERS Nano‐Biosensor

We integrated molecularly imprinted polymers with surface‐enhanced Raman spectroscopy (MIPs‐SERS) to develop an innovative nano‐biosensor for the determination of chloramphenicol (CAP) in milk and honey products. Template molecule (CAP), functional monomer (acrylamide), cross‐linking agent (ethylene glycol dimethacrylate), initiator (2,2’‐azobis(isobutyronitrile)), and porogen (methanol) were employed to form MIPs via “dummy” precipitation polymerization. Static and kinetic studies validated the specific selectivity of MIPs toward CAP over nonimprinted polymers (imprinting factor >4). Canadian penny‐based silver nano‐structure was synthesized as SERS‐active substrate for determination of CAP in food matrices. Collected spectra were processed by principal component analysis to differentiate various concentrations of CAP in foods. Partial least squares regression models showed good prediction values (R > 0.9) of actual spiked contents (0, 0.1, 0.5, 1, 5 ppm) of CAP in milk and honey. This developed nano‐biosensor is low cost, requires little sample pretreatment, and can provide reliable detection of trace level of chemical hazards in food systems within a total of 15 min.     

Rapid Detection of Melamine in Tap Water and Milk Using Conjugated “One‐Step” Molecularly Imprinted Polymers‐Surface Enhanced Raman Spectroscopic Sensor

An innovative “one‐step” sensor conjugating molecularly imprinted polymers and surface enhanced Raman spectroscopic‐active substrate (MIPs‐SERS) was investigated for simultaneous extraction and determination of melamine in tap water and milk. This sensor was fabricated by integrating silver nanoparticles (AgNPs) with MIPs synthesized by bulk polymerization of melamine (template), methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross‐linking agent), and 2,2’‐azobisisobutyronitrile (initiator). Static and kinetic adsorption tests validated the specific affinity of MIPs‐AgNPs to melamine and the rapid adsorption equilibration rate. Principal component analysis segregated SERS spectral features of tap water and milk samples with different melamine concentrations. Partial least squares regression models correlated melamine concentrations in tap water and skim milk with SERS spectral features. The limit of detection (LOD) and limit of quantification (LOQ) of melamine in tap water were determined as 0.0019 and 0.0064 mmol/L, while the LOD and LOQ were 0.0165 and 0.055 mmol/L for the determination of melamine in skim milk. However, this sensor is not ideal to quantify melamine in tap water and skim milk. By conjugating MIPs with SERS‐active substrate (that is, AgNPs), reproducibility of SERS spectral features was increased, resulting in more accurate detection. The time required to determine melamine in tap water and milk were 6 and 25 min, respectively. The low LOD, LOQ, and rapid detection confirm the potential of applying this sensor for accurate and high‐throughput detection of melamine in tap water and milk.     

基于癸硫醇修饰的银纳米点阵列的苯并(a)芘检测

利用阳极氧化铝模板法制备大面积高度有序的可调控的银纳米点阵列,并在其表面组装一层癸硫醇单分子层用于水中苯并(a)芘(benzo(a)pyrene,Ba P)的快速检测。首先,通过扫描电镜、紫外-可见透过光谱、罗丹明6G探针分子对不同扩孔时间制备的银纳米点阵列进行表征,结果表明扩孔时间为80 min制备的基底拉曼增强效果最好,增强因子可达1.6×10~6。然后,在此基底表面修饰一层癸硫醇分子,利用癸硫醇与BaP之间的疏水相互作用可以实现BaP的预富集,进而实现BaP的高灵敏度、稳定的检测。研究表明:利用此基底检测Ba P的检测限可达1.0 ng/mL,特征峰处的相对标准偏差为9.7%,满足高稳定性表面增强拉曼光谱基底的标准。该方法在BaP快速检测方面具有极大的潜力。     

Cover Caption

April Online Cover : SEMs and EM field distributions of silver nanofilm‐coated anodic aluminum oxide SERS‐active substrates, from “Fabrication of SERS‐Active Substrates using Silver Nanofilm‐Coated Porous Anodic Aluminum Oxide for Detection of Antibiotics” by Jing Chen, Shaolong Feng, Fang Gao, Edward Grant, Jie Xu, Shuo Wang, Qian Huang, and Xiaonan Lu; p. N834.     

银纳米粒子基底制备及表面增强拉曼光谱法检测荧光素钠

目的制备具有增强效应的银纳米粒子作为表面增强拉曼光谱的基底,应用于荧光素钠色素的检测,提供一种快速、方便、超灵敏的检测手段。方法用水热法制备银纳米粒子作为表面增强拉曼光谱的基底,通过紫外可见吸收光谱研究以及对比不同激发波长作用下的银纳米粒子增强效应,优化实验条件,对不同浓度的荧光素钠色素进行检测。结果银纳米粒子基底展现出了超灵敏的检测限度和超高的增强效应,在激发波长514 nm、激光强度1 mw、收集时间5 s的实验条件下,荧光素钠色素分子的检测限度达3.01×10~(-4) mg/kg。结论本方法制备的银纳米材料可作为表面增强拉曼光谱的基底,有效应用于荧光素钠色素的检测中,在进口食品安全监测中具有重要的应用价值。     

Trace analysis of organic compounds in foods with surface‐enhanced Raman spectroscopy: Methodology,progress, and challenges

Surface‐enhanced Raman spectroscopy (SERS) provides a potential solution for rapid analysis of trace compounds such as residual pesticides, naturally occurred toxicants, banned or restricted drugs, and food additives in complex food matrices. In this review, the basic principles of SERS and general approaches to successfully apply SERS in food analysis are covered from an applications perspective. The key steps including substrate selection and evaluation, sample preparation and simplification, spectral collection, and data analysis during the development of SERS methods for food analysis are summarized, together with the discussion of typical underlying technical barriers or major challenges of these methods and their applications. Future directions in successfully applying SERS technology as a routine analytical approach to solve real‐world food problems are analyzed. This comprehensive review summarizes the recent progress on theory, application, and scope of SERS for food analysis, providing a basic understanding of the technology; more importantly, key methodology, potential pitfalls, and possible solutions during the development of rapid SERS methods based on authors’ years of SERS experience are shared with researchers in the field.     

表面增强拉曼光谱技术在食品安全检测中的最新研究进展

食品种类繁多,食品中存在的污染物问题也越来越复杂。因此,探究快速、灵敏、简单地检测食品中痕量污染物的检测技术对保障食品安全具有重要的意义,也是食品安全中非常重要的一环。近几十年来,表面增强拉曼散射(surface-enhanced Raman scattering, SERS)检测技术凭借其检测快速、无损、灵敏度高等优点,已成为食品安全检测的可靠工具。目前缺乏近几年关于SERS检测技术最新研究进展的概述。因此,本文简要综述了SERS的增强机制、增强底物及其检测技术;总结了近3年来关于表面增强拉曼光谱在食品安全检测方面的实际应用。为了更好地将SERS检测技术应用于今后食品安全的常规检测中,应研发更加低成本的技术,更简单的操作方法,开发新的SERS增强底物,将SERS检测与其他检测方法更好的结合。     

基于表面增强拉曼光谱适配体传感器检测植物蛋白肉中的黄曲霉毒素B1

目的 随着生活水平的提高,经济社会的发展,面对丰富多样的食品种类,保证饮食安全已成为民众关注的重点。然而,食品中的黄曲霉毒素B1（Aflatoxin B1,AFB1）的存在对人类健康构成了极大的威胁。因此,开发一种快速、简单、灵敏的AFB1检测方法,对食品安全十分必要和迫切。方法 研发了一种检测AFB1的表面增强拉曼散射(surface enhancement of Raman scattering, SERS)适配体传感器,传感器由巯基适配体（SH-DNA）修饰的金包四氧化三铁磁性纳米粒子（Fe3O4@AuMNPs）作为捕获底物与巯基适配体互补链（SH-cDNA）修饰的金包二氧化硅纳米粒子（SiO2@Au-MBANPS）作为信号探针所组成。通过适配体与AFB1的特异性结合可以导致捕获底物释放信号探针,SERS信号强度随着AFB1的浓度的变化而发生变化,从而实现对AFB1的检测。结果 通过实验条件的优化,得到线性回归方程为Y= -222.07lgX+ 5723.12,r2= 0.9986的标准曲线,检出限为0.37 pg/mL。该SERS传感器成功应用于实际样品中AFB1的分析,得到回收率为98% ~ 110%,相对标准偏差值为3.9% ~ 5.7%。结论 本研究建立的SERS适配体传感系统可以实现对AFB1的定量检测,可以清楚识别AFB1与其他毒素的SERS信号强度差别,为AFB1的快速检测提供了新的检测方法,在实际样品植物蛋白肉中表现出优异的检测性能。     

基于氧化石墨烯的表面增强拉曼光谱技术在食品污染物检测中的应用

表面增强拉曼光谱(surface enhanced Raman spectroscopy, SERS)通过吸附表面的目标分子来增强拉曼散射,能够以高灵敏度、高特异性和高选择性检测目标分子,已成为快速检测食品污染物的一种常见技术。SERS技术的发展很大程度上依赖于SERS基底的构建与发展,常用的SERS基底材料主要为贵金属(Au、Ag和Cu),并且氧化石墨烯(graphene oxide, GO)也是一种具有拉曼活性的探针分子,可通过与贵金属的协同作用来增强表面增强拉曼光谱的信号,此外GO材料本身的自清洁性、稳定性和优越的分子吸附特性等,使得基于GO的SERS生物传感器的开发成为研究的热点。本文系统地介绍了GOSERS基底材料,综述了其在多种农药、霉菌毒素和非法添加剂等食品污染物检测中的研究应用,并对其应用进行总结和前景展望。本文旨在为GO SERS传感器的应用研究提供参考。     

Rapid Detection of Melamine in Milk Using Immunological Separation and Surface Enhanced Raman Spectroscopy

We integrated immunological separation and surface‐enhanced Raman spectroscopy (SERS) to detect melamine in milk. Antimelamine was produced by New Zealand white rabbits following the injection with melamine hapten‐ovalbumin immunogen. Melamine was separated from milk by binding to the converted protein G‐antimelamine complex. After releasing antimelamine and melamine from the complex, the eluents were deposited directly onto the silver dendrite SERS‐active substrate for spectral collection. Multivariate statistical analysis including unsupervised principal component analysis and supervised soft independent modeling of class analogy validated the feasibility of applying this method to detect trace levels of melamine in milk. The limit of detection can be as low as 0.79×10^–3 mmol/L. The overall analysis can be completed in 20 min, thus, it is a high‐throughput technique to screen for melamine in milk samples.     

表面增强拉曼散射技术对白酒中克百威残留的定性检测

建立表面增强拉曼散射（surface enhanced Raman scattering,SERS）技术对白酒中的克百威残留进行定性检测方法。制备金溶胶（Au nanoparticles,Au NPS）和不同Ag壳厚度的银包金纳米粒子（Au@Ag NPS）,通过探测分子罗丹明B（R6G）比较Au NPS和不同Ag壳厚度Au@Ag NPS的SERS增强效果;碱性条件下,向克百威分子引入标记物2,6-二氯醌-4-氯亚胺,再与增强效果较好的NPS按比例混合进行拉曼测试,讨论SERS信号采集条件,并对拉曼谱峰进行比较和归属,计算克百威在Au@Ag NPS增强基底上的增强因子。结果表明：克百威、标记物和Au@Ag NPS的比例为1∶0.225∶7,约7 nm Ag壳厚度Au@Ag NPS效果最好,克百威的检测下限为1×10－16 mol/L,Au@Ag NPS增强因子为2×108,用此方法检测3 种市售白酒中均含有微量的克百威,方法快速、简便、结果可靠。     

Recent advances in nanofabrication techniques for SERS substrates and their applications in food safety analysis

ABSTRACT

The ability to analyze food safety and quality in a quick, sensitive, and reliable manner is of high importance in food industry. Surface-enhanced Raman scattering (SERS), which is popular for its significant enhancement, excellent sensitivity, and the fingerprinting ability to identify special molecules, has shown vast potential for rapid detection of chemical constitutes, chemical contaminants, and pathogens in food sample. For SERS, the enhancement of Raman signals is related to not only the SERS-active substrates, but also the interactions between sample and substrates. In the current review, colloidal and solid surface-based substrates are briefly described, fabrication techniques for SERS substrates are presented, and applications of SERS for food matrixes, correlation between substrates and food samples are also introduced. Finally, some outlook on further developments is presented. The current review is therefore intended to provide a comprehensive overview on the nanofabrication of SERS substrates, and the potential of applying SERS as an important food analysis platform.     

Surface‐Enhanced Raman Spectroscopy for the Chemical Analysis of Food

Surface‐enhanced Raman spectroscopy (SERS) is an emerging and promising technique for the chemical analysis of food. The use of metallic nanosubstrates improves the sensitivity and capacity of conventional Raman spectroscopy greatly. This paper comprehensively reviews the development and applications of SERS in the chemical analysis of food, mainly focusing on food additives and chemical contaminants. The progress of SERS development and their applications in chemical analysis of food, from detection and characterization of target analytes in simple solvents to complex food matrices, is summarized. The advantages and limitations of different SERS substrates and methodologies are discussed. As most of the current SERS research on chemical analysis of food is still in an early stage, there are still several hurdles for further advancing SERS techniques into real‐world applications for complex food products. This review includes our perspectives on the future trends of the SERS technique in the field of food analysis.     

表面增强拉曼光谱方法在食品安全检测中的应用研究进展

近年来国内外频发的食品安全事件使得公众对食品安全问题的关注度不断提高,快速、灵敏、可靠的评估食品质量与安全的能力在食品行业中十分重要,因此开发满足食品安全需求的高性能检测技术势在必行。表面增强拉曼光谱（surface-enhanced Raman spectroscopy, SERS）具有高特异性、高灵敏度、无损检测、可实现多重检测等优异性能,在食品安全检测领域得到广泛应用,并取得了令人瞩目的进展。本文介绍了SERS技术的理论基础,总结了增强SERS信号强度的活性基底,综述了基于SERS方法的食品安全检测应用研究进展,讨论了其未来发展趋势与前景,旨在为研究人员根据具体食品安全检测应用需求选择合适的SERS方法提供建议。     

表面增强拉曼技术在农药残留检测中的应用研究进展

食品的农药残留问题是威胁人类健康的全球性问题,表面增强拉曼光谱技术(surface-enhanced Raman spectroscopy, SERS)作为一种操作简便、快速灵敏的指纹光谱技术,在农药残留检测方面已展现出较大潜力。本文首先描述了SERS增强原理,然后简单概括了SERS基底制备的方法,以基底功能性出发,介绍了食品中农残检测中常见的两种类型的SERS基底：通用型基底、特异性基底,通过综述近年来在食品农残检测中的应用,总结了二者在检测食品中农残的特点和常用的制备工艺,旨在为更多农残检测需求提供关于SERS技术方面的启发。最后展望了SERS技术在农残检测的挑战并提出可行的建议。     

Aptamer‐Based SERS Detection of Lysozyme on a Food‐Handling Surface

Undeclared food allergens due to cross contamination of processing equipment is a leading cause for food product recalls. Therefore, there is a great need for developing rapid and sensitive methods to detect food allergens. In this paper, an aptamer highly specific to egg white lysozyme was coupled to dendritic silver nanoparticles in order to perform surface enhanced Raman spectroscopy (SERS). The procedure was successfully tested in water and on a stainless steel food‐handling surface. The lowest detectable concentration for lysozyme was 0.5 μg/mL in water and 5 μg/mL on a stainless steel food‐handling surface. Principal component analysis shows a significant change in SERS spectra when lysozyme was present, suggesting the successful capture of lysozyme by the aptamer. Quantification of lysozyme target was also shown from 0 to 6 μg/mL, that is, 0, 0.5, 2, 6 μg/mL. Overall method took less than 40 min. The developed method can be extended to detect other food allergens using specific aptamers.     

表面增强拉曼光谱技术在快速检测保健食品中非法添加药物中的应用

表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)技术作为一种新型的快速检测技术正在被广泛应用于保健食品非法添加化学药物的检测中。通过设计不同的SERS基底,可以搭建出集样品前处理、上机分析、匹配定性的一体化拉曼光谱检测系统。与传统的检测方式相比,SERS技术具有无损、快速、图谱指纹特性强等优点,在保健食品非法添加化学药物的快速检测中具有巨大潜力。本文主要综述了SERS的技术原理、SERS基底分类以及SERS技术在保健食品中非法添加化学药物检测中的应用,并对SERS技术在保健食品中非法添加化学药物检测方面的应用前景进行了展望,以期为保健食品中未知违禁物的识别提供理论支撑。     

表面增强拉曼光谱在食品添加剂和违法添加物检测中的应用

表面增强拉曼光谱技术作为一种新兴的分析检测技术,在食品快速检测行业具有广阔的应用前景。文章简述了表面增强拉曼光谱技术在食品添加剂及违法添加物快速检测中的最新研究状况,并展开讨论,以期为表面增强拉曼光谱技术在食品检测领域提供参考。     

Functionalization techniques for improving SERS substrates and their applications in food safety evaluation: A review of recent research trends

BackgroundFood safety and quality have gained much attention in recent years and the capability to evaluate food quality and safety in a sensitive, rapid, and reliable manner is of great importance in the food industry. Therefore, surface-enhanced Raman scattering (SERS) with the advantages of excellent sensitivity, high selectivity, non-destructive nature and significant enhancement to identify the target has demonstrated a great potential for quick detection of chemical contaminants, chemical constitutes, and pathogens in food samples.Scope and approachThe enhancement of Raman signals for SERS is not only related to the interactions between substrates and samples but also the functionalization of substrates to gain SERS active substrates. In the present review, different types of substrates are briefly discussed, functionalization techniques for SERS active substrates are discussed, and applications of functionalized SERS substrate in food samples are presented.Conclusions and key findingsIt is evident that functionalization techniques for improving SERS substrates have given encouraging outcomes, which provides possibility for identifying multiple target analytes within a complex matrix, and thus could be used as a powerful analytical tool in real-world applications in food safety analysis as well as for enhancing food quality surveillance.