Application Notes: LC-MS

Mercury pollution mainly originates from industrial activities such as chlorine production, garbage incineration and above all coal-fueled power generation. The US Environmental Protection Agency (US EPA) considers mercury as highly toxic with a pronounced accumulative and persistent character.

An effective UHPLC-MS method for high throughput separation, identification and quantitation of pseudoephedrine was developed on a Hypersil GOLD™ PFP 1.9 µm, 2.1 x 100 mm column.

Two of the most commonly occurring unpleasant odor-causing compounds in drinking water are geosmin and 2-methylisoborneol (MIB) (Figure 1). Geosmin is produced primarily by blue-green algae (cyanobacteria) and actinomycete bacteria, and MIB is produced by certain species of cyanobacteria, primarily Oscillatoria. Many environmental laboratories are required to detect these compounds as low as 1–3 ppt concentration and measure quantitatively at 5 ppt.

The United States Geological Survey (USGS) has found pharmaceuticals and personal-care products (PPCPs) containing known or suspected endocrine-disruptors in U.S. rivers. As such, it is important to use adequate techniques to help identify these compounds and possible metabolites.

Mycotoxins, toxic secondary metabolites of several fungal species, represent food safety issues of high concern. Deoxynivalenol, the most abundant trichothecene mycotoxin, can be found worldwide as a contaminant of wheat, barley, maize and other cereals (1,2). The transmission of deoxynivalenol from barley into beer has been reported in several studies (3,4). Therefore, its levels should be controlled.

Supercritical fluid chromatography (SFC) is a normal phase separation technique. In SFC, supercritical CO2 in combination with one or more polar organic solvents, most commonly alcohols, is used as the mobile phase. Owing to the lack of intermolecular interactions, supercritical fluid typically possesses lower viscosity and higher diffusivity than those solvents used in traditional high performance liquid chromatography (HPLC). This allows for higher flow rates, faster analyses, and the use of longer columns for higher chromatographic efficiencies. Initially deemed a niche chromatographic technique for chiral separation, the horizon of SFC applications has rapidly expanded to include achiral analyses of natural products, biodiesel, oligomer, pesticides/herbicides, and peptides. This is due, in part, to the improvements in detection choices and performances for SFC. Evaporative light scattering detectors (ELSDs) coupled with SFC have found wide use in many pharmaceutical and chemical laboratories (1).

This application note describes a fast and sensitive LC-MS method using a Hypersil GOLDâ„¢ column on a Thermo Scientific LC-MS system for the quantitative analysis of two widespread PFCs, perfluorooctanoic acid (PFOA) and perfluorooctansulfonate (PFOS).

There has been an increasing interest in the presence and availability of compounds in plant materials that may possess bioactive properties, in particular, antioxidant activity. Some of these compounds have been attributed to possess anticancer, antiaging, and antimutagenic properties as well as other health benefits (1). The types of plants that have been investigated cover a vast range from common foodstuffs to regional or exotic materials. Plant parts under study have included portions that are traditionally known to be edible, as well as sections that are considered "waste" or used for animal forage. Because most screening techniques involve lengthy separations, high throughput HPLC methods are desirable.

The analysis of polar compounds in support of clinical and preclinical pharmacokinetic studies requires an analytical methodology capable of achieving ultra-low detection and quantification limits. The high sensitivity afforded by coupling HPLC with tandem mass spectrometry (MS-MS) has made it the technique of choice in this environment, but it is subject to the following limitations when reversed phase liquid chromatography (RPLC) is used:

In March 2007, several North American manufacturers of pet food voluntarily issued nationwide recall notices for some of their products that were reportedly associated with renal failure in pets. The raw material wheat gluten, used to manufacture the pet food, was imported from China and was identified as the source of contamination.

The analysis of polar compounds in support of clinical and pre-clinical pharmacokinetic studies requires an analytical methodology capable of achieving ultra-low detection and quantification limits. The high sensitivity afforded by coupling HPLC with tandem mass spectrometry (MS–MS) has made it the technique of choice in this environment, but it is subject to the following limitations when reversed phase liquid chromatography (RPLC) is used

Multidimensional liquid chromatography (MDLC) techniques are essential for the separation of highly complex proteomic samples. Advantages of off-line MDLC techniques over on-line approaches include high flexibility in choice of column dimensions and mobile-phase compositions, and the ability to reanalyse sample fractions. Here we present a fully automated off-line two-dimensional chromatographic approach for the analysis of proteomic samples using an UltiMate 3000 system optimized for proteomics MDLC.

This article describes a fully automated online solid-phase extraction–liquid chromatography–tandem mass spectrometry (SPE–LC–MS-MS) setup using a mass spectrometer and an electrospray ionization probe for analyzing different groups of polar contaminants in natural waters. The goal was to develop an online SPE method for the quantification of sulfonamide antibiotics, including their acetyl metabolites, as well as for frequently used pesticides (triketones, phenylureas, chloracetanilides, phenoxyacetic acids, amides, and triazines) in ambient waters. The analytical methods were applied successfully for a field study in an agricultural region within the catchment area of Lake Greifensee near Zurich, Switzerland.

Drug discovery scientists are continually striving to improve productivity and efficiency in their workflows. From early discovery to clinical development, existing workflow bottlenecks represent an opportunity to develop solutions to speed the process and improve productivity. The key requirements for quantitative analysis are precision, accuracy, and linear dynamic range. With any quantitative instrument, the hope is that it will be applicable to a vast range of coumpounds, ruggest, and fast. New mass spectrometry (MS) technologies are being developed that meet these criteria and permit high throughput while enabling its application to areas in which speed limitations previously curtailed its practicality. In particular, in the area of ADME profiling, new MS platforms are becoming available that increase the throughput by at least 25-fold, by combining the speed of matrix-assisted laser desorption ionization (MALDI) with the specificity of triple-quadrupole MS. This is bound to greatly accelerate the ADME..

Mass spectrometry has become a fundamental tool for compound identification or confirmation by virtue of its ability to obtain elemental composition determination (formula identification) by accurate mass measurements. The speed, sensitivity, and ease of interfacing the technique with gas chromatography and liquid chromatography make it the technique of choice for many applications. However, accurate mass measurements must be made with care, and sometimes they can require careful calibration procedures and validation methods. In addition to accurate mass measurements, the isotope abundance distribution also provides information unique to a given chemical formula. However, the mass spectral accuracy required for accurate isotope modeling has not been easy to obtain previously. More recent approaches (1–3) that calibrate the spectral line-shape show promise in obtaining the necessary level of spectral accuracy but still require careful calibration methods with the use of known standards. This article..

This application note describes an LC–MS–MS method for on-line sample preparation and concentration of drinking water samples prior to analysis using a triple quadrupole with full scan Q3 confirmation.

One problem frequently encountered in LC–MS is the appearance of mass peaks, which appear totally unrelated to the samples run - "ghost" mass peaks. It is impossible to differentiate whether these signals come from an unknown component in the sample co-eluting with a known peak, or from an impurity in the mobile phase or from some residual contamination "bleeding" from the column.

Preliminary studies of biodiesel samples by a high speed LC–MS system using electrospray ionization and a patented cone-wash feature demonstrate that LC–MS reduces the analysis time to 20 minutes and reveals information about higher molecular weight compounds in biodiesel while still detecting many low molecular weight chemicals, including FAMEs, at high sensitivity.

The use of 30 mm UPLC columns coupled with Oasis SPE in µElution format was investigated to increase the speed of quantitative bioanalytical methods while maintaining sensitivity and resolution of closely related analytes.

AC Analytical Controls developed a new chromatographic solution that complies with all ASTM & EN chromatographic test methods listed in biodiesel specifications: the AC all-in-one Biodiesel analyser. Analysis results demonstrate that the AC analyser complies with EN 14103, EN 14105, EN 14106, EN 14110 & ASTM D6584 methods.

TN012 Sulfanilamides from Honey using strata-X-C phenomenex

LC–MS–MS methods for the unambiguous identification and quantification of pesticides in complex matrix samples are well known and widely used. Triple quadrupole systems have proven useful for this task because of their high specificity in MS–MS mode and their low detection limits. However, working in targetted MS–MS mode prevents the detection of other compounds.

The continual increase in sample numbers in busy labs means that it is often difficult for quality control or contract analysis labs to maintain short turnaround times, particularly when instruments are already running at full capacity. To address the need for faster analysis while retaining the quality of separation offered by dedicated amino acid analysers, an improved formulation of sodium citrate based buffers has been developed by Biochrom.