Industrial application of green chromatography--I. Separation and analysis of niacinamide in skincare creams using pure water as the mobile phase.

In this work, chromatographic separation of niacin and niacinamide using pure water as the sole component in the mobile phase has been investigated. The separation and analysis of niacinamide have been optimized using three columns at different temperatures and various flow rates. Our results clearly demonstrate that separation and analysis of niacinamide from skincare products can be achieved using pure water as the eluent at 60°C on a Waters XTerra MS C18 column, a Waters XBridge C18 column, or at 80°C on a Hamilton PRP-1 column. The separation efficiency, quantification quality, and analysis time of this new method are at least comparable with those of the traditional HPLC methods. Compared with traditional HPLC, the major advantage of this newly developed green chromatography technique is the elimination of organic solvents required in the HPLC mobile phase. In addition, the pure water chromatography separations described in this work can be directly applied in industrial plant settings without further modification of the existing HPLC equipment.

Application of photoassisted electrochemical detection to explosive-containing environmental samples.

High-performance liquid chromatography (HPLC) with ultraviolet (UV) absorbance and photoassisted electrochemical detection (PAED) is applied to the determination of explosives in groundwater and soil samples. On-line, solid-phase extraction minimizes sample pretreatment, enabling direct analysis of groundwater samples and soil extracts. Soils are extracted using pressurized fluid extraction, which is compared to the Environmental Protection Agency (EPA) sonication method. Limits of detection for explosives in the matrixes of interest are equivalent or superior (i.e., <10 parts-per-trillion for HMX) to those achieved using the EPA method 8330. HPLC-UV-PAED is also shown here to be more broadly applicable, as it is capable of determining nitro compounds of interest (e.g., nitroglycerin) that have poor UV chromophores. Additional selectivity of amine-substituted nitroaromatic explosives is achieved by using a photochemical reactor with a 366-nm wavelength lamp. By coupling reversed-phase columns of different selectivities together, baseline resolution of all 14 standard explosives is demonstrated.

A platform for on-site environmental analysis of explosives using high performance liquid chromatography with UV absorbance and photo-assisted electrochemical detection.

High-performance liquid chromatography with photo-assisted electrochemical detection (HPLC-PAED) is used in conjunction with ultraviolet absorbance (UV) detection for determining explosives in environmental samples. The system utilizes an on-line solid-phase extraction technique for sample pretreatment (i.e., fractionation and concentration), thus reducing the required ground water sample size from 1L to 2mL and minimizing sample handling. Limits of detection for explosives using solid-phase extraction and PAED range from 0.0007 to 0.4mug/L, well below those achieved with UV detection for several important explosives (e.g., RDX). The method has demonstrated good accuracy, precision, and recovery for all tested explosives, thus proving that the method is suitable for evaluation of explosives in ground water with competitive advantages over the U.S. Environmental Protection Agency (EPA) Method 8330. A system adaptable for the on-site environmental analysis of explosives has been developed and validated.

Carbohydrate analysis of bacterial polysaccharides by high-pH anion-exchange chromatography and online polarimetric determination of absolute configuration.

A significant problem in structure determination of complex carbohydrates, especially for bacterial polysaccharides, is determination of the absolute configuration of the component monosaccharides. A number of analytical methods have been used for this purpose but, as a result of the wide variety of chemical properties of sugars found in complex polysaccharides, no single method is universally applicable. High-resolution gas chromatography of volatile derivatives with chiral reagents is the most widely used method. Optical activity, although direct and simple, lacks sensitivity generally requiring a large quantity of pure monosaccharide. We report a combination of high-performance anion-exchange chromatography (HPAEC) with combined electrochemical pulsed amperometric detection and in-line detection of optical rotation with an in-line laser polarimeter for analysis of a number of sugars found in complex polysaccharides. We show that application of the method for analysis of capsular polysaccharides of several gram-positive and gram-negative pathogenic bacteria provides useful information simultaneously on carbohydrate composition and the enantiomeric configuration of component sugars.