Analytical Derivatization Techniques ☆

Abstract

For the last 40 years or so, analytical chemists have borrowed well-known reaction techniques from organic and organometallic fields to perform derivatization reactions so as to enhance detection of the elusive analytes they seek. The derivatization mantra has been that, for the technique to be worthwhile, it should be simple to perform, fast (usually less than 15 min), selective, and that the derivatizing reagent should react quantitatively with the analyte and only give one final product. So where are we now? Some derivatization reactions are indeed fast and some are not; some are very selective and some are more universal. However, with a certain care and careful control of optimized conditions, quantitative enhancement outcomes and increased separative power and detection can be very worthwhile. The number of derivatization reagents commercially available itself suggests that there must be some merit to derivatization, that overcomes the associated extra costs: in time (to incorporate the extra reaction step), and in the expense of acquiring, handling, and storing derivatizing reagents. This chapter attempts to show that with proper consideration, it has been feasible to push a chosen analytical technique to give increased selective detection and signal enhancement by derivatization. In many cases, this has made possible the detection of trace components from difficult matrices in a number of scenarios, including on-site analysis, in quality control/continuous analysis methods, or through some remote-sensing platforms. Further, the incorporation of derivatization in an extraction method can be simple and friendly to automated throughput for multiple sample analysis.The fundamental idea of derivatization is that the basic chemical or physical structure of the analytical moiety is changed through a suitable reaction. For example, by labeling compounds for a specific detection purpose, or by changing a functional group to enhance certain chromatographic characteristics, better detection and separation (respectively) can be achieved via the ensuing instrumental techniques. The type of derivatization is highly dependent upon the analytical method and upon the nature of the compound analyzed. There are a variety of good review articles, technical reports, 1 text chapters, 2 and full texts 3-6 that address in detail many specific applications used in analytical derivatization. There are several extraction methods available that are compatible with derivatization. For many analyses, the choice of the best extraction technique is not clear, as many techniques can extract analytes equally well, based on simplicity, applicability, solvent use, expense, detection limit, precision, and time taken to perform the operation. 7 Derivatization techniques have been incorporated into many sample preparation and extractions schemes, to include, but not limited to, total sample headspace, single-drop microextraction (SDME), 8 solid-phase microextraction (SPME), needle trap device (NTD), purge and trap, solid-phase extraction (SPE)...

Derivatizing Reagents for Detection of Organic Compounds By HPLC

“…The derivative is in a reaction coil, the length of which is controlled by the time required for completion of the reaction, and is then measured in the detector. [5,6,11].…”

Modern Methods of Sample Preparation for the Analysis of Oxylipins in Biological Samples

“…The derivatization step is determined by the chosen analytical method. For liquid chromatography (LC) using spectrophotometric and fluorimetric detectors, derivatization allows compounds to be obtained which are sensitive to these types of detectors [162]. Derivatization can also be used as a diagnostic tool to determine which functional groups exist in the oxylipin molecule (hydroxyl groups, carbonyl groups, etc.).…”

Gas-Diffusion Microextraction (GDME) Combined with Derivatization for Assessing Beer Staling Aldehydes: Validation and Application

“…In the last 10 years, different extraction techniques have been applied for the analysis of carbonyl compounds in alcoholic beverages, such as headspace solid-phase microextraction (HS-SPME) [17,18] and stir bar sorptive extraction (SBSE) [19,20]. Derivatization techniques are also a good strategy to improve the volatility and extraction of semi-volatile compounds, as well as to improve its stability [21] and detectability during LC-UV analysis [22]. Our research group has applied the gas-diffusion microextraction (GDME) extraction procedure for the identification of several carbonyl compounds in different liquid and solid matrices ( [23][24][25][26]).…”