Application Notes

Salt formation is a critical aspect in drug development (1) and HPLC is an important tool for determination of pharmaceutical counterions. Reversed-phase columns often fail to retain very hydrophilic counterions. Ion chromatography (IC) is preferred for selective and sensitive screening of cationic and anionic pharmaceutical counterions (2), usually with multiple runs. Positive and negative counterions can be separated simultaneously using a zwitterionic HILIC column using an evaporative light scattering detector (3). However, the zwitterionic column method has limitations: 1) limited to HILIC mode; 2) ions are retained as salts rather than via ion-exchange, making method development difficult; and 3) the method is not suitable for simultaneous separation of acidic, basic, and neutral analytes.

D-Mannose-6-phosphate (M-6-P) is a terminal monosaccharide of some asparagine-linked (N-linked) oligosaccharides and is also part of an important intermediate in N-linked oligosaccharide biosynthesis. Some lysosomal glycoproteins require M-6-P terminated oligosaccharides for proper targeting and function. Lack of M-6-P or genetic defects in its synthesis or subsequent processing can result in a variety of diseases.

This application note describes a fast LC method for the analysis of water-soluble vitamins using a Thermo Scientific Hypersil GOLD aQ column.

Since the USA Patriot Act* has been enacted, many pharmaceutical companies have reformulated their over the counter (OTC) drug products with phenylephrine (a nasal decongestant) as a substitute for pseudoephedrine. Phenylephrine comes as a tablet, a liquid, or a dissolving strip to take orally - all as a treatment for cold symptoms (1). Besides phenylephrine, most pharmaceutical formulations for common cold and sinus medications often contain multiple active ingredients to treat different types of symptoms in addition to numerous excipients. From an analytical perspective, the challenge is to develop chromatographic conditions that allow quantitative analysis of a variety of excipients that vary widely in hydrophobic properties.

Since September 2008, 294 000 infants and young children suffered urinary problems as a result of the contamination of melamine in infant milk powder and were hospitalized. This hospitalization was required to treat the symptoms caused by the ingestion of melamine contaminated infant formula and related dairy products. Previously in 2007, pet food, animal feed wheat gluten and other protein-based foods were found to contain residues of melamine and its degradation product cyanuric acid.

Using HILIC with highly efficient ethylene bridged hybrid (BEH) particles results in faster methods that exhibit improved polar retention, higher sensitivity, enhanced chromatographic resolution and significantly improved column lifetime.

LC/GC approaches to analysis are attractive because they combine the selectivity of solid-phase sorbents in the first dimension with the separating power and peak capacity of capillary GC in the following dimensions.

Hydrophilic interaction liquid chromatography (HILIC) offers unique advantages for the separation of very polar compounds when compared to reversed-phase chromatography. A new silica based HILIC phase was developed to provide additional selectivity options in HILIC separations. The separation of water soluble vitamins on the new TSKgel NH2-100 HILIC column and on the well known TSKgel Amide-80 HILIC column demonstrates the differences in selectivity.

Forensic laboratories face a daunting task to identify trace amounts of controlled substances in small samples of seized evidence. Unambiguous identification is required to meet the stiff challenge that is sure to be raised in the courtroom. Positive proof is especially difficult to establish if the controlled substance is hidden in a complex food matrix with a high content of sugars, fats, fatty acids, proteins and alkaloids.

GC–MS method is presented for the quantitative determination and confirmation of melamine residues in milk products. The milk sample was cleaned up using Agilent's SampliQ SCX SPE cartridges before derivatization. The derived extracts were analysed by GC–MS with EI in synchronous SIM/scan mode on a Agilent J&W DB-5ms Ultra Inert column.

Penicillins are regulated substances in food for human consumption. The minimum residue limits range from 1 ng/g to as high as 50 ng/g depending on the compound. Because of the complexity of food matrices measuring the level of contaminants requires a total solution composed of sample extraction, sample clean-up, chromatographic separation and detection. In this paper, a solid-phase extraction method with a high performance liquid chromatography tandem mass spectrometry method (HPLC–MS–MS) is shown for the simultaneous determination of six antibiotic residues.

Solid phase microextraction (SPME) is a well established sampling technique that is often used to isolate volatile organic components in gaseous mixtures.

Phenols are frequently present in water because of their widespread use in commercial products and because they are by-products of processes in petrochemical, pulp and paper, plastic, and glue manufacturing industries (1,2). The concentration of phenolic compounds in the waste discharges can be as high as 20 mg/L (2); however, phenol-containing pesticides and wood preservatives may cause significant health hazards even at mg/L levels (1). Consequently, it is important to monitor phenols and substituted phenols in environmental and biological samples. Liquid chromatography with electrochemical detection is one of the widely used methods due to its high selectivity and sensitivity for phenolic compounds. However, glassy carbon working electrodes, used in the electrochemical detection of phenols, often require polishing (3). This time-consuming and often poorly reproducible polishing can be avoided with disposable carbon electrodes, which offer comparable or better analytical performance (4).

Polybrominated diphenyl ethers (PBDE) are persistent environmental contaminants that are being extensively studied by environmental researchers worldwide. Their potential for toxicological impacts on humans and wildlife has made them a focal point of regulatory agencies. Their widespread use as flame retardants in electronics, household furniture, and many other building materials has lead to a need for analysis of many different sample matrices, including very complex environmental samples.

In HPLC method development, screening of various para-meters such as stationary phase, eluents, and temperatures is conducted to find optimal resolution. However, method development can be a time consuming and inefficient process. UHPLC technology can be applied to significantly shorten both the analysis and development times. Here we describe an integrated and ultrafast automated method scouting solution that provides fast and efficient method development processes.

Perflourinated organic acids are ubiquitous and found at relatively low concentrations in the environment (1). Trifluoroacetic acid (TFA) is the persistent atmospheric degradation product of hydrofluorocarbons (HFCs) that are increasingly used as an alternative to banned, ozone-damaging chlorofluorocarbons (CFCs). However, debate surrounds the use of HFCs because of their potential to contribute to global warming and demonstrated toxicity to the environment (2). TFA is also widely used in pharmaceutical and biotechnology purification processes. It is crucial to monitor for TFA in environmental risk assessment and in products intended for human use. TFA can be measured by gas chromatography (GC) after sample preparation and chemical derivatization (3), ion chromatography (IC) (4), and capillary electrophoresis (5). This paper describes an IC-MS method to separate TFA from common anions based on Reagent-Freeâ„¢ IC (RFICâ„¢) technology with sensitive and selective mass spectrometric detection.

Gel Permeation Chromatography (GPC) is widely used for sample clean up in mycotoxin analysis. The most commonly described methods use GPC columns packed with SX-3 BioBeads suitable for cleaning Zearalenone, Aflatoxins, and Trichothesenes from edible oils and fatty matrices. Separation of Fumonisins from the oil fraction are inadequate with this column.

The recent establishment of a 1 μg/g safety threshold for melamine in infant foods has led to an immediate need for more sensitive methods. Here we established GC–MS conditions for highly reproducible analyses and evaluated the effectiveness of both solvent-based and matrix-matched standards. Using this method, melamine and cyanuric acid were reliably detected at and below 1 μg/g in infant formula.

The Biochrom 30 Amino Acid Analyser is a well established analytical instrument for clinical diagnosis as its IVD approval allows the diagnosis of inborn errors of metabolism such as Phenylketonuria.

Thermal agility is a term that describes the ability of an oven to heat up and cool down. Both steps comprise the complete cycle time which, in turn, determines sample throughput. Fast GC accessories provide an attractive means of increasing sample throughput because they are easy to implement and deliver reliable performance at low cost. They require little or no bench space and do not incur additional costs for consumables and support equipment such as autosamplers, data acquisition software, and computers. Fast oven cooling is especially attractive because methods do not have to be re-validated since the separation parameters remain unchanged.

Achieve highly reproducible cIEF separations of basic mAbs using the basic pH gradient cIEF separation method on the PA 800 Protein Characterization System.

Development of cephalosporin antibiotics has led to compounds with a broad spectrum of activity against both Gram-positive and Gram-negative bacteria with low toxicity profiles. Cefepime, a fourth-generation cephalosporin, is a commonly prescribed broad spectrum antibiotic with improved activity against Gram-negative bacteria compared to other commercially available cephalosporins (1). Despite extensive research on this class of drugs, quantitative analysis and purity assays remain problematic (2).

EPA Method 8260 is used to determine volatile organic compounds (VOC's) in a variety of matrices including ground and surface waters. This method is commonly used in environmental laboratories where gas chromatography (GC), mass spectrometry (MS) and purge and trap (P&T) technology are used for the analysis and subsequent detection of VOC's.

Run a difficult food sample on your IC and you stand a big chance that you will wreck the column. Of course, you can waste a lot of time on tedious sample preparation steps to eliminate undesired matrix components. Or you can go for Metrohm's automated compact stopped-flow dialysis providing optimum separation while protecting your column from detrimental compounds.

This method is rapid and sensitive for the analysis of melamine and cyanuric acid simultaneously in infant formula. Using two Oasis solid-phase extraction protocols and the ACQUITY UPLC, the results are consistent with the published US FDA interim method, while demonstrating a reduced analysis time.

Melamine is an industrial chemical with a high nitrogen content that can cause kidney stones and lead to renal failure. In some instances, melamine has been added to baby formula and dairy products as a substitute for protein. This paper presents an efficient and definitive gas chromatography–mass spectrometry (GC–MS) method to identify melamine and related compounds based on the released US Food and Drug Administration (FDA) method.

Carbonyl compounds, including low molecular weight aldehydes and ketones, have environmental and health concerns; for example, short-term exposure to aldehydes can irritate the eyes, skin, and upper respiratory tract. Motor vehicles emit reactive hydrocarbons that undergo photochemical oxidation in the atmosphere, which generates formaldehyde and other carbonyls. In addition, formaldehyde contributes to the formation of photochemical ozone. California Air Resources Board (CARB) Method 1004 (1) provides an analytical method for the automotive industry to monitor 13 carbonyl compounds in engine exhaust. US EPA Method TO-11A (2) and Method 8315 (3) monitor atmospheric formaldehyde and 14 other carbonyl compounds and are used for a variety of environmental and occupational health purposes. In these methods, carbonyl compounds are trapped as the dinitrophenylhydrazine (DNPH) derivatives before analysis by HPLC.

Thermo

Purge and trap concentration (P&T) along with gas chromatographic analysis is a widely used method for the detection of volatile organic compounds (VOCs). This methodology was developed to achieve the high sensitivity necessary to determine VOCs in drinking water according to EPA Method 524.2. Research is now complete and the EPA currently proposes a revision to this method that may include a revised list of analytes including iodinated trihalomethanes, fuel oxygenates, and Contaminant Candidate List 3. This new method will be 524.3 and may include new parameter optimizations not previously permitted in 524.2 as well as the ability to use selective ion monitoring (SIM) analysis for troublesome compounds.

Residual solvents in pharmaceuticals are defined as volatile organic chemicals that are used or produced in the manufacture of drug substances, excipients or in the preparation of drug products. Because residual solvents do not provide therapeutic benefits, they should be removed, to the extent possible. Drug products should contain no higher levels of residual solvents than can be supported by safety data. Looking forward to the implementation of a revised USP <467> method, Teledyne Tekmar evaluated the new protocol, therefore this application will comply with the procedure and criteria changes set forth in the USP30 NF25, Second Supplement (effective December 1, 2007) and the interim revision announcement. (1)