Liquid chromatography techniques

Thruston Jr., A. D., High-pressure liquid chromatography techniques for the isolation and identification of organics in drinking water extracts, /. Chromatogr. Sci., 16, 254, 1978. 

Applications Figure 4.7 shows the general areas of application of liquid chromatography techniques. 

Despite its potential importance, formic acid has proven difficult to quantify at submicromolar levels in non-saline water samples. Formidable analytical difficulties are associated with its detection in highly saline samples. Ion exclusion, anion exchange, and reversed-phase high performance liquid chromatography techniques based on the direct detection of formic acid in aqueous samples are prone to interferences (especially from inorganic salts) that ultimately limit the sensitivity of these methods. 

The isocratic system (Fig. 1.2 (a)) provides an economic first step into high-performance liquid chromatography techniques. The system is built around a high-performance, dual-piston, pulse-free pump providing precision flow from 0.01 to 5ml min-1. 

The main element in the paper is presentation of the possibilities for using the liquid chromatography technique for screening compounds with regard to their biological properties. Examples of different uses of chromatographic methods in on-line analysis of the bioactivity of mixture ingredients are also described. 

High performance liquid chromatography techniques may be successfiilly applied to analyze phthalate esters. A 15 or 25 cm column filled with 5 or 10 pm silica-based packings is suitable. Short columns (3.3 cm x 4.6 mm), commonly called 3x3 columns, offer sufficient efficiency and reduce analysis time and solvent consumption Phthalate esters resolve rapidly on a 3 x 3 Supelcosil LC-8 column (3 pm packing) at 35°C and detected by a UV detector at 254 nm. Acetonitrile-water is used as mobile phase (flow rate 2 ml/min injection volume 1 mL). Other equivalent columns under optimized conditions may be used. 

Dash, K., S. Thangavel, N.V. Krishnamurthy, S.V. Rao, D. Karunasagar, and J. Arunachalam. 2005. Ultrasound-assisted analyte extraction for the determination of sulfate and elemental sulfur in zinc sulfide by different liquid chromatography techniques. Analyst 130 498-501. 

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