Application Finder

For SERS developers and end users of SERS for specific applications to investigate low concetation levels of compounds, the centerpiece of their technological platform must be a Raman setup that provides reliable lab grade performance and is affordable and portable, allowing them to tackle real world problems. The portable i-Raman Plus system coupled with a BAC151 video microscope sampling accessory provides an ideal setup. With the performance and flexibility of use with different laser spot size and power for SERS research.

Brilliant Blue (BB) FCF, more commonly known as FD&C Blue #1, is the most commonly used blue dye worldwide for food and beverages. It is generally accepted as safe and non-toxic. Aside from foods labelled as organic or as free from artificial dyes, there is little objection to the use of BB at levels at or exceeding 100 μg/g in foods.This application for Misa (Metrohm Instant SERS Analyzer) is unique. The benefit is twofold — successful detection of a fluorescent dye, and a unique sample cleanup technique that permits detection of a target that does not exhibit a strong SERS signal and is present in a complex matrix. While Misa successfully detects BB in direct sampling, this application describes a simple extraction method that improves detectability of BB with Misa.

Substrates for surface-enhanced Raman spectroscopy (SERS) are typically fabricated with complex (micro/nano)structures of noble metals, enabling trace level detection of analytes. Due to the high costs and reactivity of these SERS substrates, they often have a limited shelf life. Development of new substrate materials which minimize these issues yet maintain the same performance standards is a constant concern.Screen-printed electrodes can be easily fabricated using different metallic materials with the well-established screen-printing method, leading to mass production of versatile, cost-effective, and disposable devices. In this Application Note, the feasibility of using readily-available screen-printed metal electrodes as suitable substrates for the fast and sensitive detection of different chemical species by in situ electrochemical SERS (EC-SERS) is shown.

Surface Enhanced Raman Scattering or SERS is an anomalous enhancement of Raman scattering when molecules are adsorbed to gold or silver nanoparticles – this enhancement can be as large as 107. The advantage of SERS for the analytical chemist lies in its ability to detect analyte concentrations of parts per million and even parts per billion levels, while classical Raman is limited to parts per thousand. Metrohm Raman produces P-SERS assays in the form of nanoparticles printed onto substrates using inkjet technology. This method produces inexpensive test strips that exhibit exceptional stability and sensitivity. There are two markets that can be easily addressed with P-SERS: forensic analysisand food safety. This white paper explains the mechanism of SERS and how it can be applied to handheld Raman analysis with Metrohm Raman Mira systems.

Low sensitivity has limited the use of Raman spectroscopy as a detection method. However, the surface-enhanced Raman scattering (SERS) effect has improved its effectivity for analytical use. Aldehyde dehydrogenase (ALDH) and cytochrome c are analyzed by Raman spectroelectrochemistry as a proof of concept in this Application Note.

Yaba, produced in Southeast Asia, is a popular drug of abuse and is actively targeted by police squads. Two strong and highly addictive stimulants make up Yaba: caffeine, which comprises up to 60% of each tablet, and methamphetamine at approximately 20%. Identifying these two active ingredients in different proportions in a colorful tablet with other excipients could be an analytical nightmare. With handheld Raman, bulk material identification is achieved in seconds onsite with simple point-and-shoot analysis. SERS (surface-enhanced Raman spectroscopy) analysis is used to detect the minor component in mixtures without interference from fillers, dyes, and coatings. MIRA DS is uniquely capable of both analyses—Raman testing positively identifies caffeine in Yaba, while methamphetamine can be detected with SERS sampling. This application describes quick, dual analysis of Yaba tablets with MIRA DS.

Many electrochemical methods have been developed but are traditionally limited to aqueous media. Raman spectroelectrochemistry in organic solutions is an interesting alternative, but developing new EC-SERS procedures is still required. This Application Note demonstrates that the electrochemical activation of gold and silver electrodes enables the detection of dyes and pesticides in organic media.

Metanil yellow (MY) is an azo dye used in the manufacture of external-use products such as textiles; however, it is prohibited from use as a food additive in many countries. Toxicology studies demonstrate that ingestion of MY results in significant neurological and multi-organ damage. Despite these hazards, MY is commonly used as an illicit colorant for enhancing the visual appeal of spices and legumes, most notably turmeric. Ideal tests for such food adulterants feature methods that are selective and sensitive, yet portable and convenient.Misa (Metrohm Instant SERS Analyzer) achieves rapid and accurate detection of MY in a facile assay format.

Handheld Raman spectrometers are valued for their ability to provide onsite material identification in seconds. In the case of combination pharmaceuticals, a single tablet contains more than one active ingredient in different proportions. MIRA DS is uniquely capable of identifying multiple compounds in such tablets by using Raman to identify the major component and SERS (surface-enhanced Raman spectroscopy) for the minor component. This application describes quick, dual analysis of a prescription medication containing acetaminophen and hydrocodone. The application is easily extrapolated to the study of street drugs.

Voltammetry (VA) is a fast and established method for testing the remaining antioxidant content in industrial lubricants. The flexible and modular Metrohm VA system setup discussed in this White Paper delivers more repeatable and more reproducible results which fulfill all ASTM requirements. Additionally, users can automate the complete analysis process which makes it possible to run series of samples completely unattended.

In this work, time resolved Raman spectroelectrochemistry measurements with screen printed electrodes are shown. The instrument used combines in a totally integrated box: a 785 nm laser source, a high resolution Raman spectrometer and a bipotentiostat/galvanostat. Experiments are controlled with an excellent spectroelectrochemical software which allows real time data collection and useful data treatment.

The TacticID®-GP Plus has multiple measurement modes to support safety and security users. A-Mode allows the user to create library Raman or SERS spectra customizable for spectral search range and hit quality index (HQI) threshold. A-mode is of beneficial use to forensics laboratories that would like to utilize expansion of SERS detection of designer drugs specific to their geographical regions or for food safety in perspective markets. In this example, A-Mode is used to create a SERS library of melamine to easily detect the presence of melamine in infant formula using a single indicator peak.

An important aspect of collecting Raman data to make it comparable across instruments is correcting for the spectrometer’s relative intensity, since the relative response for each Raman spectrometer is unique. Standard reference materials (SRMs) are optical glasses that emit a broadband luminescence spectrum when illuminated with a Raman laser at a specific wavelength. This spectrum is applied as the spectral-intensity response correction for a specific instrument, to remove instrumental artefacts. The standard software for i-Raman series portable instruments, BWSpec, has functions for applying this instrument-specific correction. This technical note explains the relative intensity correction, and how to apply it using BWSpec software.

Analyzer systems monitoring product quality can offer substantial advantages when organized in a client-server network compared to the more traditional local installation. This white paper presents different client-server setups and their benefits. Security aspects that need to be considered are discussed based on the example of the client-server Vis-NIR (visible near-infrared) spectroscopy software Vision Air, widely used for quality control in the chemical, polymer, pharmaceutical, and petrochemical industry.

SERS (Surface-Enhanced Raman Scattering) detection of a toxic dye (Sudan 1) used to adulterate saffron demonstrates the power of MISA (Metrohm Instant SERS Analyzer) for simple, portable food authentication in this Application Note.

The emergence of counterfeit prescription drugs has become a concern for the pharmaceutical industry. Because of the low concentrations of APIs found in pharmaceutical drugs, normal Raman spectroscopy is typically not sensitive enough to detect the API from the surface of a pill. In this study we develop a surface-enhanced Raman spectroscopy (SERS)-based approach to identify a low-dose of the API alprazolam in a Xanax tablet using a handheld Raman spectrometer. If no SERS peaks consistent with alprazolam are observed from a Xanax tablet, the pill is a suspected fake. The method demonstrates the power of SERS to quickly verify the presence of alprazolam in the tablet for anti-counterfeiting purposes.

Printable Surface Enhanced Raman Scattering (P-SERS) silver substrates were used with Metrohm Raman’s Mira DS handheld Raman analyzer to successfully detect heroin in 18 crude street heroin samples. Detection of heroin with P-SERS was accomplished easily and very quickly, with minimal sample clean-up. Solvent studies were also implemented to determine the optimal solvent for crude sample extraction, with results included here.

Raman analysis of fentanyl-soaked paper, SERS detection range for fentanyl on paper, and real-world example of fentanyl identification.

Fenthion is a multi-purpose insecticide used in many countries for mosquito control. To minimize human exposure and the unintentional poisoning of wildlife, the US EPA has classified fenthion as a restricted-use insecticide. However, the widespread spraying of olive orchards in Mediterranean countries results in olive oils that occasionally exceed the maximum residue limits established for olives.Misa (Metrohm Instant SERS Analyzer) easily achieves sensitive trace detection of fenthion in spiked olive oil after a simple organic solvent extraction. This Application Note presents an excellent example of how the signal from SERS substrates can compete with the target signal at very low levels of detection.

Malathion is an insecticide widely used on a broad spectrum of plant species. Several studies have implicated chronic exposure to malathion in the development of certain cancers. Maximum residue limits for malathion have been enacted by the regulatory agencies of several countries: the US Food and Drug Administration sets maximum residue limits at 8 μg/g in foods, while the EU has a considerably more stringent limit of 20 ng/g.SERS is an accepted method for detection of malathion on fruit and vegetable surfaces. Misa (Metrohm Instant SERS Analyzer), which requires minimal laboratory chemicals and consumables and provides an extremely user-friendly interface, is an excellent SERS solution for trace detection of food adulterants.

Raman spectroscopy is used widely by law enforcement as a field screening tool due to its speed, selectivity and ease of use. The majority of materials can be identified by the Raman signature, as they exhibit sharp distinctive peaks serving as a molecular fingerprint. However, many street and real-world samples are dark in color and not pure. The dark color, often due to impurities, gives rise to fluorescence that interferes with the Raman measurement. One method to suppress the fluorescence of a sample and enhance the Raman activity / signal is by the use of Surface-Enhanced Raman Spectroscopy (SERS).

In this Application Note, MISA (Metrohm Instant SERS Analyzer) from Metrohm Raman excels in the detection of the pesticide acetamiprid on commercially sold raisins. MISA is a viable alternative to analytical laboratory testing in the quest to prevent contaminated foods from reaching and harming consumers.

Fentanyl, a powerful synthetic opioid, is illegally distributed worldwide. Overdosing can be fatal, causing symptoms like stupor, pupil changes, cyanosis, and respiratory failure. Just 2 mg of fentanyl can be lethal, depending on factors like body size and past usage. Given its severe impact, identifying and detecting fentanyl is crucial, as it has become a major public health crisis. Combining electrochemical surface-enhanced Raman spectroscopy (EC-SERS) with screen-printed electrodes (SPEs) offers a fast, effective, and precise method for detecting fentanyl.

Potassium ferrocyanide (KFC) is an anti-caking compound added to table salt. Although this is a common non-toxic food additive, its spectroscopic response is representative of analogous cyanide compounds. Trace detection of other cyanides in food products is essential to the safety of consumers, as they can be toxic at oral consumption levels as low as 20 μg/g.This application demonstrates rapid trace analysis of potassium ferrocyanide in table salt with Misa (Metrohm Instant SERS Analyzer), in a simple assay format with minimal use of laboratory reagents.

Pyrimethanil is a broad-spectrum fungicide. As grapevines are susceptible to fungal pathogens, large-scale viticulture operations apply pyrimethanil as part of a mixed treatment. Although chemical analysis of wines post-fermentation finds low to undetectable amounts of residue, pyrimethanil is a suspected human carcinogen. The US FDA and EU have therefore established a maximum permissible level of 5 μg/mL pyrimethanil in finished wine products.In this application, trace detection of pyrimethanil in wine with Misa (Metrohm Instant SERS Analyzer) requires few laboratory supplies and minimal sample processing, yet returns rapid results.

Auramine O (AO) is an industrial dye used for a broad range of manufactured products and as a fluorescent stain for detecting acid-fast bacteria in clinical specimens. Due to its intense yellow coloration, AO is also prized as an additive for enhancing the visual appeal of illicitly processed food products. Despite bans on AO as a food additive, surveillance testing indicates its persistent use as an adulterant in foods and spices.Misa (Metrohm Instant SERS Analyzer) achieves the rapid and sensitive detection of AO in curry powder in a simple assay format.

Thiram is used extensively as a fungicide and parasiticide to prevent disease in crops and as an animal repellent to protect trees and ornamental plants. However, extensive toxicological studies conclude that chronic, high-level exposure can cause considerable organ damage to land and aquatic species. The US defines maximum residue limits that vary for different food crops. In contrast, the EU recently banned thiram and is moving to use pesticides that carry reduced health risks.Using Misa (Metrohm Instant SERS Analyzer), low level detection of thiram on apples is achieved with guided workflows adapted for use by diverse testers.

Rhodamine B is a dye utilized extensively in biotechnology and industrial applications and is one of several colorants banned for use as food additives in Europe and North America. The most common analytical methods for detection of illicit dyes in food products, GC/MS and HPLC, are laboratory-based instrumental methods that require specialized training.With Misa (Metrohm Instant SERS Analyzer), detection of trace amounts of Rhodamine B in ground cayenne pepper is quick and easy after a facile extraction procedure with minimal material consumption. Rhodamine B can be detected in cayenne powder at a concentrations as low as 10 µg/g.

Carbendazim (MBC) is a common fungicide approved for regulated use in agriculture globally, outside of the EU. Most MBC is found on fruits as surface contamination, the result of sprays applied prior to harvest. The US EPA has determined that a concentrations below 80 μg/mL in orange juice are not a health risk, while the EU restricts MBC levels to 10 ng/g (from imported produce) in foods intended for baby food production.This Application Note describes a very simple test for surface MBC and provides library spectra demonstrating the sensitive detection of MBC with Misa (Metrohm Instant SERS Analyzer).

Thiabendazole (TBZ) is a broad-spectrum pesticide used both as a fungicide in fruits and vegetables and for controlling parasites in animal feed. To ensure consumer safety, regulatory agencies establish maximum residue levels (MRL) for pesticide-treated crops based on their review of risk assessment studies. For bananas, which are either aerially sprayed or dipped in protectant solutions of TBZ, the US FDA reports a MRL of 3 μg/g, and the EU stipulates a MRL of 6 μg/g by weight.With Misa (Metrohm Instant SERS Analyzer), the rapid and sensitive detection of TBZ on bananas is demonstrated in formats easily adapted for food safety surveillance testing.

In 2008, a scandal was discovered in China that melamine was being deliberately added to raw milk. Thousands of young children and infants that consumed formula produced from melamine-tainted milk experienced kidney damage and death. As a result, both daily intake limits and increased monitoring of melamine in dairy products were established globally.Misa (Metrohm Instant SERS Analyzer) provides quick, easy, and robust detection of melamine in a complex food matrix. As a direct test with no additional reagents, Misa’s assay format requires minimal user training, in contrast to standard analytical tests for detecting melamine, including capillary electrophoresis, GC-MS, LC-MS, and immune-based assays.

Erythrosine B (EB), also known as Red Dye #3, is a synthetic dye approved for use in candy in the US, and in pharmaceuticals and cosmetics in the EU and elsewhere. However, rodent studies suggest that ingestion of EB can promote thyroid tumor formation. EB may also be implicated as a dietary factor contributing to hyperkinesis in children. WHO recommends a daily intake of EB less than 0.1 mg/kg of body weight.The ability to obtain fast results with a portable test platform recommends Misa (Metrohm Instant SERS Analyzer) as a competitive and cost-effective alternative to laboratory technologies (e.g., CE, HPLC) currently employed for detecting EB in foodstuffs.

Malachite green (MG) is a textile dye with effective fungicidal properties, however it is acutely toxic and its metabolites persist in the flesh of fish and mammals, making it a threat to the human food chain. The EU has concluded that contaminated foods containing levels higher than 2 μg/g MG constitute a credible health risk, and several countries have banned malachite green as an aquaculture additive. Despite tight regulation, seafood products contaminated with MG continue to find their way to consumers.Using Misa (Metrohm Instant SERS Analyzer) to ensure food safety, the rapid and highly sensitive detection of malachite green is achieved in a facile assay format.

Some studies suggest that consumption of the artificial sweetener, aspartame, is correlated with increased risk for brain and hematopoietic cancers, however, others find it to be a safe food additive. Consequently, the US and EU approve aspartame as a multi-purpose sweetener with an acceptable daily intake of 40 mg/kg body weight/day. However, the clear health hazard to individuals suffering from phenlyketonuria and ongoing criticism by health food advocates continues to fuel the challenge against aspartame’s widespread use in the food industry.Using Misa (Metrohm Instant SERS Analyzer), beverage products are screened for aspartame levels with no sample preparation beyond simple dilution of a consumer product.

Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are proving to be invaluable tools in the field of biomedical research and clinical diagnostics. Raman systems are also being developed for molecular diagnostic testing to detect and measure human cancer biomarkers. This review highlights two applications realting to breast cancer and pancreatic cancer diagnosis together with examples of the use of Raman spectrometry in biomedical research areas such as the identification of bacterial infections, showing that Raman is an important part of the medical toolbox, as we continually strive to improve diagnostic techniques and bring a better health care system to patients.

Diphenylamine (DPA) is used as a dye fixative and antioxidant in industrial applications and as a produce preservative in agricultural operations. Food safety advocates are concerned that daily ingestion of DPA, particularly in foods meant for babies, could have negative effects on children’s health. To mitigate potentially toxic effects of DPA, both the US and EU stipulate a maximum residue limit (MRL) of 5 μg/g for whole pears and a stringent MRL of 10 ng/g for all processed baby foods.Misa (Metrohm Instant SERS Analyzer) provides a user-friendly and cost-effective alternative to traditional analytical methods used for detecting DPA in foods, such as GC-MS and GC-NPD.

Although the process of building, validating and using a method is well-defined through software, the robustness of the method is dependent on proper practice of sampling, validation, and method maintenance. In this document, we will detail the recommended practices for using the multivariate method with NanoRam-1064. These practices are recommended for end users who are in the pharmaceutical environment, and can expand to other industries as well. This document aims to serve as a general reference for NanoRam-1064 users who would like to build an SOP for method development, validation and implementation.

The lactulose/rhamnose (L/R) intestinal permeability test is used for the diagnosis of dysfunctional intestinal permeabilities. This test comprises the determination of mannitol, rhamnose, lactose and lactulose in addition to the usual blood sugars, e.g. glucose, galactose and saccharose. This Application Note presents the analysis of a blood plasma sample enriched with the four sugars mentioned above.Key word: leaky gut syndrome

B&W Tek’s TacticID®-1064 is a field-ready handheld Raman system utilizing 1064-nm wavelength laser excitation. Designed for forensic analysis by safety personnel, first responders, and law enforcement personnel, the TacticID-1064 significantly reduces fluorescence, allowing users to identify tough street samples such as ecstasy tablets in a variety of colors and mixture forms.

The column stability of the Metrosep C 6 - 250/4.0 was determined in long-term laboratory tests. Two injection series per day were run on each of six days in a row. Each series was comprised of nine tap water injections, three check standard injections and six tap water injections. The IC system was shut down on the seventh day of each series. As a whole, the system ran over 10 weeks and counted a total of 2,150 injections. The results show an outstanding reproducibility and verify the high column stability.

The stability of the Metrosep A Supp 5 - 250/4.0 column was determined in long-term laboratory tests. Two injection series each were run on six days in a row. Each series was comprised of nine tap water injections, three check standard injections and six tap water injections. The IC system was shut down on the seventh day of each series. As a whole, the IC system ran over 10 weeks and counted a total of 2,150 injections. The results show an outstanding reproducibility and verify the high column stability.

The column stability of the microbore version of the Metrosep A Supp 5 - 250/2.0 was determined in long-term laboratory tests. Two injection series each were run on six days in a row. Each series was comprised of nine tap water injections, three check standard injections and six tap water injections. The IC system was shut down on the seventh day of each series. As a whole, the IC system ran over 12 weeks and counted a total of 2,650 injections. The results show an outstanding reproducibility and verify the high column stability.

This Application Bulletin serves as the manual for the "Polytron PT 1300 D" (Polytron) homogenizer.

The «MVA-20» is a fully automated system for the determination of suppressor, brightener, and leveler in plating solutions in small sample series.

Raman instrumentation can use lasers of different laser excitation, giving the same Raman spectrum for a sample. This paper presents the specific strengths and weaknesses that different excitation wavelengths provide, allowing a user to optimize the measurement of different samples by their choice of Raman excitation laser wavelength.

This article demonstrates the utility of portable Raman spectroscopy as a versatile tool for process analytical technology (PAT) for raw material identification, in-situ monitoring of reactions in developing active pharmaceutical ingredients (APIs), and for real-time process monitoring. Raw material identification is done for verification of starting materials as required by PIC/S and cGMP, and can be readily done with handheld Raman. Portable Raman systems allow users to make measurements to bring process understanding and also provide proof of concept for the Raman measurements to be implemented in pilot plants or large-scale production sites. For known reactions which are repetitively performed or for continuous online process monitoring of reactions, Raman provides a convenient solution for process understanding and the basis for process control.

Forensics testing of samples encountered by law enforcement and customs agents is based on analytical techniques that are now being miniaturized and simplified and are making their way into field instrumentation. Field testing with Raman spectroscopy allows users to conduct reliable measurements at the point of arrest, reducing the burden on crime labs and accelerating the prosecution process.

Cellulose is a common naturally-derived raw excipient found in the majority of pharmaceutical products. Raw material testing is required to ensure that consumers are receiving quality cellulose and its derivatives. The NanoRam®-1064 is an asset for pharmaceutical identity testing, minimizing fluorescence generated by typical handheld Raman systems with 785 nm lasers. As such, the NanoRam®-1064 is used here to identify cellulose derivatives that would normally fluoresce with a 785 nm laser.

The two potentiometric titration methods described here allow the determination of the content of commercial betaine solutions. Neither method is suitable for determining the betaine content of formulations. The possibilities and limits of both methods are described and distinctive features and possible sources of interference are mentioned. The Bulletin explains the most important theoretical principles and is intended to help users to develop their own product-specific titration methods.

In this application note, Karl Fischer titration is used to determine water content in sodium acetate trihydrate. The MATi 10 allows this determination to be automated, saving users time in the laboratory.