Search

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.

In this article portable Raman spectroscopy as an effective tool for at-line characterization of carbon black is presented. Raman spectroscopic analysis can be an effective test to characterize carbon black material, including the structural order.

Raman spectroscopy is a well suited spectroscopic technique for process development and control within development laboratories in chemical, pharmaceutical, and other industries. This article demonstrates the utility of portable Raman spectroscopy as a simple and versatile tool for in situ monitoring of reactions using univariate analysis techniques such as peak trending, as well as multivariate analysis approaches to predict the end point of chemical reactions.

Portable Raman is used to quantify trigonelline, an alkaloid that contributes to the health benefits of some foods. A simple method to quantify the presence of diluted trigonelline in solutions using surface enhanced Raman spectroscopy is described. Portable Raman is a tool that could be used in quality control of food items such as coffee and quinoa.

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.

This Application Note describes the Raman spectroscopy identification of sugars such as D-galactose, D-glucose, D-maltose, D-mannose, D-sorbitol, fructose, sucrose and inositol. Rapid and non-destructive determination takes place after a suitable spectrum database has been created. Measurements with the portable Raman spectrometer Mira M-1 require no sample preparation and provide immediate and unambiguous results.

Raman spectroscopy is used for material characterization by analyzing molecular or crystal symmetrical vibrations and rotations that are excited by a laser, and exhibit vibrations specific to the molecular bonds and crystal arrangements in the molecules. Raman technology is a valuable tool in distinguishing different polymorphs. Examples of portable Raman spectroscopy for identification of polymorphs and in monitoring the polymorphic transiton of citric acid and its hydrated form are presented.

The suitability and potential of Raman spectroscopy in forensics is widely known by forensic specialists who use it in the laboratory to identify a wide variety of compounds including explosives, drugs, paints, textile fibers and inks. However, the use of laboratory-grade Raman outside the laboratory, such as for in‐situ analysis at a crime scene, was something thought possible only in forensic‐fiction until just a few years ago. Fortunately, modern portable Raman spectrometers are commercially available, and their instrumental features are comparable to Raman lab‐ spectrometers.To prove this, some extraordinarily demanding and challenging applications, in which an in‐situ standoff identification of samples might be advisable, were tested.

Today's Raman instrumentation is faster, more rugged, and less expensive than in the past and the advances in component miniaturization have led to the design of portable devices with extremely high performance designed for field-based investigations. This study focuses on the use of handheld Raman spectroscopy for the characterization and identification of samples encountered in various application areas related to forensic science.

Content uniformity of solid dosage forms can be done nondestructively at the process line using the QTRam portable transmission Raman system.

Edible oils are not only a major source of nutrition but also a key basic material in the food industry. Vegetable oils are increasingly important because of their high content in mono- and polyunsaturated fatty acids in comparison with animal fats. In this application note, the main ingredients of olive oil, camellia oil, arachis oil, sunflower seed oil, and colza oil are analyzed using a portable Raman spectrometer combined with chemometrics software.

At a crime scene, a police officer collects a fiber sample that may prove to be invaluable evidence in identifying a criminal or exonerating an innocent person. In recent years, Raman spectroscopy has been studied extensively for forensic fiber analysis because of the high selectivity of Raman signatures, non-destruction nature of the test, and the ability to conduct the analysis without any sample preparation. The Raman spectrum can be measured directly on fabrics or fibers mounted on glass slide with very little interference from the mounting resin or the glass.

Analytical methods to perform CU testing should ideally be fast, noninvasive and achieved with limited sample preparation. Recently, transmission near-infrared (NIR) spectroscopy and transmission Raman spectroscopy have both been explored as alternative methods for rapid and non-destructive on- and at-line CU testing with no sample preparation. Although quick and nondestructive, transmission NIR spectroscopy suffers from poor chemical selectivity and is sensitive to changes in the testing environment. Transmission Raman spectroscopy combined with chemometric modeling is quickly emerging as a valued technique for CU testing due to its high chemical specificity, which is particularly useful when dealing with complex pharmaceutical formulations that contain multiple components.

Ternary mixtures of aqueous sugar solutions are measured and multivariate models of the concentration of analytes developed using BWIQ software.

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.

Portable Raman spectroscopy is an invaluable tool in the study of archaeological sites, allowing for in situ analysis which minimizes the impact of such studies on important cultural sites. The flexibility of the use of a fiber optic probe and tripod-mounted video microscope with a light weight instrument reduces the need for sampling, and increases the ability to make representative measurements over what can be very large sample areas. The information content of Raman spectroscopy aids in the understanding of the materials used in the construction and restoration of important archaeological sites, and in understanding the degradation that is occurring which should aid in preservation and restoration work.

Correct identification of mineral phases in rock thin sections is essential to petrographic and petrologic analysis of rocks. Portable Raman coupled to an optical microscope gives chemical information along with the optical images to give a higher certainty of identification than traditionally used optical micropcopy alone.

This Application Bulletin compares the unique focusing technology of the portable Metrohm Raman system "Mira" with conventional methods. The method described here is called Orbital Raster Scan (ORS). Experiments show the advantages of ORS technology, using determination and quantification of medicines as an example. It improves the reproducibility of the Raman signals from targeted, active, pharmaceutical ingredients (APIs) in effervescent, cold medicines. Shorter analysis times and an improved, consistent assignment of spectra of the known medicine with the help of a spectral library are further advantages of ORS technology.

Today’s Raman instrumentation is faster, more rugged, and less expensive than previous instrumentation.The design of high performance, portable and handheld devices has introduced the technology to new application areas that were previously not possible with older, more cumbersome instruments. Handheld Raman instruments such as the NanoRam® from B&W Tek are well-suited for pharmaceutical applications such as the testing of raw materials, verification of final products and the identification of counterfeit drugs due to the technique’s extremely high molecular selectivity.

Portable Raman is used to characterize the quality of diamond foils made by CVD processes.

Quantitation of the functionalization of a water-soluble polymer was achieved using a portable Raman spectrometer. The Raman spectrum provides strong, unique bands for both the initial and fully reacted polymer. This enables development of a simple, robust quantitative analysis of the percent polymer functionalization. This method is now routinely used in a manufacturing plant's quality control laboratory.

Stamps are cultural heritage objects that provide an invaluable amount of historical information. There is an increase of counterfeit historical inks and it is imperative that fraudulent stamps can be identified and removed from the market. The portable Raman i-Raman EX® with a 1064 nm laser is used because it minimizes the fluorescence of the ink. The i-Raman EX® also has the functionality of low laser power reduction down to 1% to prevent sample burning and the Raman video microscope system analyzes the smallest of details, which is imperative for cultural heritage analysis of an 1885 historical envelope.

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.

This Application Note compares SPELEC RAMAN and a standard Raman instrument by analyzing their performance in measuring single-walled carbon nanotubes (SWCNT).

Research laboratories must expand their capabilities to routinely analyze candidate microplastics from environmental samples to determine their origin and help predict biological impacts. Spectroscopic techniques are well suited to polymer identification. Laboratory Raman spectroscopy is an alternative to confocal Raman microscopes and Fourier transform infrared (FTIR) microscopes for quick identification of polymer materials. Raman microscopy was used to identify very small microplastic particles in this Application Note.

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.

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.

Undeclared drugs in dietary supplements pose serious health risks. Metrohm’s SERS solutions enable fast, sensitive, on-site detection of adulterants without matrix interference

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.

Mercaptans in fuels are corrosive and regulated at trace levels. SERS enhances Raman signals to enable their accurate detection and quantification below standard LODs.

This application note presents the Orbital Raster Scan (ORS) technology from Metrohm Raman to overcome low resolution, poor sensitivity, and sample degradation while still interrogating a large sample area.

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.

Paraquat is a highly effective, yet exceptionally toxic herbicide used to manage weeds in agricultural operations. In recognition of paraquat’s danger, the EU and several other countries have banned its use for any application, though the US EPA permits its limited use by licensed applicators. Despite tight regulation, paraquat continues to be produced and is liberally used as an herbicide in over 100 countries without regulatory oversight.Testing for paraquat typically requires involved sample processing and analysis by trained chemists using expensive laboratory instruments such as HPLC, CE, and LC/MS. Misa achieves trace level detection of paraquat residue in tea leaves in a fully integrated, portable, smart system for easy on-site testing by non-technicians.

Electrochemistry, spectroscopy, and spectroelectrochemistry (SEC) are widely used techniques in many fields. However, the data curves obtained from these analyses are quite varied, and not all electrochemical peaks and spectroscopic bands can be measured with the same procedures. This Application Note examines four tools included in the DropView 8400 and DropView SPELEC softwares to facilitate the measurement and analysis of the collected curves and data. The following measurement options are explained in detail: automeasurement, set on curve measurement, set free measurement, and set step measurement.

With MISA and MIRA, easy-to-use test kits and flexible sampling allow rapid and accurate interrogation of suspect materials with minimal time, training, and expense.

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.

Alamar Blue is monitored with fluorescence spectroelectrochemistry during its irreversible reduction to resorufin and further reversible reduction to dihydroresorufin.

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.

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.

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.