High-performance liquid chromatography based methods

Cinnamyl anthranilate can be assayed by a method based on ester hydrolysis. Bulk samples of food-grade cinnamyl anthranilate have been analysed for purity by thin-layer chromatography and high-performance liquid chromatography. A method has been described for determining the content of this compound in food products by steam distillation followed by paper chromatography and examination under ultraviolet light it has a limit of detection of 1 pg (lARC, 1983). 

Seiber JN, Glotfelty DW, Lucas AD, et al. 1990. A multiresidue method by high performance liquid chromatography-based fractionation and gas chromatographic determination of trace levels of pesticides in air and water. Arch Environ Contam Toxicol 19 583-592. 

Currently, high-performance liquid chromatography (HPLC) methods have been widely used in the analysis of tocopherols and tocotrienols in food and nutrition areas. Each form of tocopherol and tocotrienol can be separated and quantified individually using HPLC with either a UV or fluorescence detector. The interferences are largely reduced after separation by HPLC. Therefore, the sensitivity and specificity of HPLC methods are much higher than those obtained with the colorimetric, polarimetric, and GC methods. Also, sample preparation in the HPLC methods is simpler and more efficiently duplicated than in the older methods. Many HPLC methods for the quantification of tocopherols and tocotrienols in various foods and biological samples have been reported. Method number 992.03 of the AOAC International Official Methods of Analysis provides an HPLC method to determine vitamin E in milk-based infant formula. It could probably be said that HPLC methods have become dominant in the analysis of tocopherols and tocotrienols. Therefore, the analytical protocols for tocopherols and tocotrienols in this unit are focused on HPLC methods. Normal and reversed-phase HPLC methods are discussed in the separation and quantification of tocopherols and tocotrienols (see Basic Protocol). Sample... 

Schroyer, B. and P. Capel (1996). A high-performance liquid chromatography-based screening method for the analysis of atrazine, alachlor, and ten of their transformation products. In M.T. Meyer and E.M. Thurman, eds., Herbicides Metabolites in Surface Water and Ground Water. ACS Symposium Series 630. Washington, DC American Chemical Society, pp. 34-42. 

Hayward, S. J., Lei, Y. D., Wania, F. (2006) Comparative evaluation of three high-performance liquid chromatography-based estimation methods for highly hydrophobic organic compounds polybrominated diphenyl ethers and hexabromocyclododecane. Environ. Toxicol Chetn., 25 2018-2027. 

S., Nath, R.G., Salem, N., Jr., and Chung, F.L. (2006) A solid-phase extraction/high -performance liquid chromatography-based 32P-postlabeling method for detection of cyclic 1,N2-propanodeoxyguanosine adducts derived from enals. Anal. Biochem., 348, 15-23. 

Many organic additives can be analysed using the technique of high performance liquid chromatography (HPLC), particularly using MS for positive identification. HPLC methods have now largely superseded thin layer chromatography (TLC)-based procedures. 

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. 

As a consequence of the previous considerations Kieber et al. [75] have developed an enzymic method to quantify formic acid in non-saline water samples at sub-micromolar concentrations. The method is based on the oxidation of formate by formate dehydrogenase with corresponding reduction of /3-nicotinamide adenine dinucleotide (j6-NAD+) to reduced -NAD+(/3-NADH) jS-NADH is quantified by reversed-phase high performance liquid chromatography with fluorimetric detection. An important feature of this method is that the enzymic reaction occurs directly in aqueous media, even seawater, and does not require sample pre-treatment other than simple filtration. The reaction proceeds at room temperature at a slightly alkaline pH (7.5-8.5), and is specific for formate with a detection limit of 0.5 im (SIN = 4) for a 200 xl injection. The precision of the method was 4.6% relative standard deviation (n = 6) for a 0.6 xM standard addition of formate to Sargasso seawater. Average re-... 

To determine how much one isomer is in excess over the other, analytical methods based on high-performance liquid chromatography (HPLC) or gas chromatography (GC) on a chiral column have proved to be most reliable. 

In this regard several sophisticated chromatographic methods, with a quantification limit down to about 0.2 ng/g, have been developed and published for the determination of zearalenone. The methods were mainly based on high-performance liquid chromatography (HPLC) with fluorescence detection (Krska 1998 Visconti and Pascale 1998 Schuhmacher et al. 1998 Tanaka et al. 2000), but HPLC with mass spectrometry detection was also used (Shirai et al. 2000 Josephs et al. 2001). 

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