Application Notes: General

In ion chromatography, the presence of a large amount of matrix ions makes quantification of the target ions difficult.

Separation of polar compounds by conventional reverse phase chromatography can be challenging due to their poor retention. Other HPLC approaches include normal phase chromatography (NPC) and its variation, hydrophilic interaction chromatography (HILIC).

Over the past several years column manufacturers have been introducing columns packed with smaller particle sizes – sub-2 µm and 3 µm – to take advantage of the improvements that such small particle size columns offer.

Since the gas flow required for the separation step in gas chromatography is frequently lower that that required to optimize the detection, nitrogen is used as a make-up gas to increase the gas flow for detection.

The characteristic composition of ionic liquids (an organic cation or anion and a counterion, in either organic or inorganic form) exhibits unique properties, such as extremely low vapor pressure, excellent thermal stability, electrical conductivity, high polarity, and miscibility with various types of solvents.

The combined benefits are demonstrated by a separation of impurities found in a sample of octyl-dimethyl-4-aminobenzoate.

Cyanide, an environmental contaminant, can cause serious health effects including goiters, hypothyroidism and some neuromuscular diseases. Cyanide wastewater sources include the plating and mining industries, burning of coal and plastics and effluent from publicly owned treatment works (POTW).

The term ionic liquid refers to organic salts with relatively low melting points (below 100 °C) that usually consist of an organic cation or anion and a counterion, in either organic or inorganic form. Ionic liquids exhibit unique characteristics such as extremely low vapour pressure, excellent thermal stability, electrical conductivity, a high degree of polarity and miscibility with various types of solvents. Ionic liquids have been used as catalysts and solvents in organic chemistry and electrochemistry and as mobile phase modifiers or functionalized stationary phases in separation science.1–3

The free and total content of detrimental glycerol in vegetable oil methyl esters (biodiesel) is of paramount importance for the quality of biodiesel and is, therefore, limited by the US ASTM D 6751 and the European EN 14214 standards. Both regulations currently stipulate gas chromatographic (GC) analysis of free and total glycerol. However, the GC method, apart from being expensive, requires tedious derivatizations and fails for glycerol determinations in coconut or palm kernel oil methyl esters.

The composition and analysis of fragrance components in home and personal care (HPC) products is very complex and unquestionably time consuming.

As UPLC users convert or replace their existing HPLC systems with UPLC systems there is a transition period where a method must be run on both platforms. Thus, having the same particle substrate and bonded phases available in HPLC and UPLC particle sizes can significantly ease the burden of method development and transfer from one platform to another. In addition to the ethylene bridged hybrid (BEH) particle, three new high strength silica (HSS) stationary phases for HPLC applications are introduced. Scalability between both column diameter and particle size is demonstrated on both UPLC and HPLC instrumentation.

Corn stover is the above-ground portion of the plant minus the kernels and it accounts for a large percentage of the global supply of lignocelluosic biomass available as feedstock for fermentation systems used for biofuel production.

According to the FDA policy statement, developing stereoisomeric drugs, each enantiomer should be evaluated.1 As a result, the pharmaceutical industry has escalated its emphasis on the generation of enantiomerically pure compounds before undertaking pharmacokinetic, metabolic, physiological and toxicological evaluations.2 Chiral chromatography, especially SFC, is the most widely used technique for obtaining mg to multigrams of pure enantiomers in drug discovery. In SFC, a combination of supercritical CO2 and polar organic solvent(s), most commonly alcohol, are used as the mobile phase. Because of the higher diffusivity and lower viscosity of supercritical fluid, SFC often provides a 3–8-fold faster separation than normal-phase HPLC. For chiral purification, SFC also offers significant cost savings by reducing organic solvent usage and removal as well as the time and energy required post-purification. As SFC instrumentation continues to improve, SFC has gradually overtaken HPLC as the first choice..

This application note describes a rapid UHPLC method for the separation of Sulforhodamine 101 (Texas Red®) and its three water-soluble derivatives using a column packed with Thermo Scientific Hypersil GOLD™ 1.9 μm particles.

BPA or bisphenol A has become well know over the past year as concerns for its effect on human health and well being have been raised. The concerns over BPA in plastics began with baby bottles and spread to include other types of bottles and toys.

Dedicated instrumentation, multiple columns and time-consuming changeovers are required in order to measure both anions and cations with ion chromatography.

Corn stover is the above-ground portion of the plant minus the kernels and it accounts for a large percentage of the global supply of lignocelluosic biomass available as feedstock for fermentation systems used for biofuel production.

The analysis of the molar mass distribution of polyethylene and polypropylene resins by GPC/SEC has always been considered a demanding task because of the requirement of high temperature operation for dissolution and complex hardware design, which often results in high maintenance cost, in particular related to the autosampler/injector and detector units, and in other problematic and consuming tasks such as solvent handling added to column fragility, sample degradation, or detector sensitivity–stability.

Acidic mobile phases have found widespread applications in the reversed-phase HPLC separation of many important pharmaceutical and environmental compounds.

The term ionic liquid refers to organic salts with relatively low melting points (below 100 °C) that usually consist of an organic cation or anion and a counterion, in either organic or inorganic form.

Various techniques exist for cutting capillary tubing. In this note we revisit these methods and provide guidelines for selecting the most appropriate method.

Since 2001 when they became available in North America, monolithic silica HPLC columns have become valuable analytical tools in the R&D and methods development laboratories.

This article describes the use of combined ion chromatography-mass spectrometry (IC–MS) and ion chromatography-inductively coupled plasma mass spectrometry (IC-ICP–MS) to analyse potentially harmful compounds.

Tobacco specific nitrosamines (TSNA) are a group of carcinogens found only in tobacco products and are formed from nicotine and related alkaloids during the production and processing of tobacco and tobacco products.

The analysis of anions and cations is critical during quality control. In this example, all major ionic components in mineral water are identified and quantified in a single run, with no sample preparation or concentration step.

Homeland security requirements create the need for portable mass spectrometers, with ion detectors capable of performing at elevated pressure.

Tobacco Specific Nitrosamines (TSNA) are a group of carcinogens found only in tobacco products and are formed from nicotine and related alkaloids during the production and processing of tobacco and tobacco products (1). Due to their carcinogenic properties, efforts have been made to reduce TSNA levels in tobacco products. The project goal was to demonstrate a high throughput and sensitive method to monitor TSNA levels.

In the past few decades, single enantiomers and stereoisomers have overtaken achiral molecules in the percentage of approved drugs in the market. Because isomers can have different biological/pharmacological/toxicological properties, authorities, such as the European Pharmacopoeia and the FDA, have asserted escalated emphasis on controlling isomer content in drug compounds and require that stereoisomers, "be treated as separate drugs and developed accordingly" with rare exception. The separation and quantification of stereoisomers is therefore of great importance, especially when considering pharmaceutical compounds (1).