Abstract: Abstract Chemical warfare agents (CWAs) are unarguably one of the most feared toxic substances produced by mankind. Their inception in conventional warfare can be traced as far back as the Middle Ages but their full breakthrough as central players in bellic conflicts was not realized until World War I. Since then, more modern CWAs along with efficient methods for their manufacture have emerged and violently shaped the way modern warfare and diplomatic relations are conducted. Owing to their mass destruction ability, counter methods to mitigate their impact appeared almost immediately on par with their development. These efforts have focused on their efficient destruction, development of medical countermeasures and their detection by modern analytical chemistry methods. The following review seeks to provide the reader with a broad introduction on their direct detection by gas chromatography-mass spectrometry (GC-MS) and the various sample derivatization methods available for the analysis of their degradation products. The review concentrates on three of the main CWA classes and includes the nerve agents, the blistering agents and lastly, the incapacitating agents. Each section begins with a brief introduction of the CWA along with discussions of reports dealing with their detection in the intact form by GC-MS. Furthermore, as products arising from their degradation carry as much importance as the agents themselves in the field of forensic analysis, the available derivatization methods of these species are presented for each CWA highlighting some examples from our lab in the Forensic Science Center at the Lawrence Livermore National Laboratory.

Abstract: DLLME is widely used as a sample preparation technique due to its unique advantages of fast extraction, low solvent consumption, high enrichment factors, and low cost. DLLME extracts are generally analyzed by gas or liquid chromatography coupled with different detection systems. However, GC or LC cannot analyze/separate many analytes due to their structural properties. Similarly, some of the analytes are not sensitive to commonly used detectors. In such cases, a derivatization process (chemical conversion) is often applied to improve the structural features of the analytes to make them compatible with separation and/or detection system. The coupling of derivatization with DLLME is a simple way to accomplish the job using minimum volumes of the derivatizing reagents and reducing their impact on workers and the environment. This review explains the different modes of DLLME coupled derivatizations, their applications, and green aspects in a systematic way.

Abstract: Nowadays, the idea of Green Analytical Chemistry (GAC) is of high importance what impacts on the rapid growth in the sample preparation area with special emphasis on sample preparation simplification, miniaturization, and automation. Because the derivatization process is often an essential element of the analytical procedure, it should be important to focus on this issue from GAC perspective and conduct a series of experiments in order to develop the most favorable conditions. Application of microextraction techniques coupled with the derivatization perfectly meets the specified requirements. Other approaches to perform derivatization process in “green” way include the application of eco-friendly solvents/reagents, enhanced parameters such as microwaves or ultrasound and application of in-port, on-column/in-capillary derivatization modes. This review describes factors that allow making derivatization process more green, different modes and ways of derivatization procedures involving less toxic, hazardous reagents/solvents and more efficient forms of energy. Moreover, microextraction techniques that are often coupled to derivatization are described with examples.

Abstract: The analysis of small polar compounds with ToF-SIMS and MALDI-ToF-MS have been generally hindered by low detection sensitivity, poor ionization efficiency, ion suppression, analyte in-source fragmentation, and background spectral interferences from either a MALDI matrix and/or endogenous tissue components. Chemical derivatization has been a well-established strategy for improved mass spectrometric detection of many small molecular weight endogenous compounds in tissues. Here, we present a devised strategy to selectively derivatize and sensitively detect catecholamines with both secondary ion ejection and laser desorption ionization strategies, which are used in many imaging mass spectrometry (IMS) experiments. Chemical derivatization of catecholamines was performed by a reaction with a synthesized permanent pyridinium-cation-containing boronic acid molecule, 4-(N-methyl)pyridinium boronic acid, through boronate ester formation (boronic acid–diol reaction). The derivatization facilitates their sensitive de...

Abstract: The determination of oxidative stress biomarkers (OSBs) is useful for the assessment of health status and progress of diseases in humans. Whereas previous methods for the determination of OSBs in urine were focused on a single marker, in this study, we present a method for simultaneous determination of biomarkers of oxidative damage to lipids, proteins, and DNA. 2,4-Dinitrophenylhydrazine (DNPH) derivatization followed by solid phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) allowed the determination of 8-hydroxy-2′-deoxyguanosine (8-OHdG), o-o′-dityrosine (diY), malondialdehyde (MDA), and four F2-isoprostane isomers: 8-iso-prostaglandinF2α (8-PGF2α), 11β-prostaglandinF2α (11-PGF2α), 15(R)-prostaglandinF2α (15-PGF2α), and 8-iso,15(R)-prostaglandinF2α (8,15-PGF2α) in urine. Derivatization with DNPH and SPE was optimized to yield greater sensitivity and selectivity for the analysis of target chemicals. The limits of detection of target analytes in urin...

Abstract: The identification of trace components from biological media can require derivatization under mild conditions for successful analysis by mass spectrometry (MS). When aqueous droplets (ca. 500 nL) containing a sugar and an amine as reagents are allowed to evaporate they may form long-lasting microthin films in which derivatization reactions can occur fast relative to reaction rates in bulk solution. Evidence is presented that these reactions are heterogeneous in nature and comparisons are made with reactions in pastes and in neat reagent mixtures. Moreover, these thin film reactors can be made stable for the long periods of time that may be necessary to give high product yields. The situation is typified by imine formation from reducing sugars which have reaction times of much more than 1 hour provided that small concentrations (e.g. 20 ppm) of nonvolatile solvents are included. After evaporation of almost all the water, the reaction occurs at an approximately constant rate for the first hour. The rate is two orders of magnitude faster than the reaction in the corresponding homogeneous saturated bulk solution. Conversion of the reagent to the Schiff base product is 67% to 96% efficient in these long-lasting thin films, in sharp contrast to the corresponding derivatization efficiencies in the bulk of less than 1%. This method was used to chemically derivatize and thus to identify, using tandem mass spectrometry, 29 reducing sugars in ca. 1 nL of intracellular fluid from a single onion epidermis cell. A formal description of the kinetics of reversible and irreversible second order reactions in thin films is provided. The effects of thermodynamic and kinetic factors are separated and the measured apparent acceleration factor is shown to represent the ratio of intrinsic rate constants for the microthin film reactor relative to the bulk reaction.

Abstract: Covering the literature from 2011 until recently, this review highlights the analytical strategies that have been adopted for the extraction and analysis by high performance liquid chromatography comprising without or with derivatization of biogenic amines in real samples of food and beverages. The alternative ways of detection by tandem mass spectrometry, potential of multiple reaction monitoring and extracted ion chromatograms have been utilized when analyses performed without any derivatization. The reagents employed for derivatization differ widely in their structures, involve a variety of reaction mechanism, and allow detection by UV-absorption, fluorescence or mass spectrometry. The development of such a large number of reagents for a single class of analytes demonstrates the continued endeavours to overcome the implicit difficulties associated with low molar mass and polar analytes in complex sample matrices, and the inherent importance of the analysis of biogenic amines. The discussion presented will allow the alternative techniques to be adopted for particular biogenic amines samples, and have better control over selectivity and sensitivity of the method.

Abstract: Simultaneous detection of oleanolic acid and ursolic acid in rat blood by in vivo microdialysis can provide important pharmacokinetics information. Microwave-assisted derivatization coupled with magnetic dispersive solid phase extraction was established for the determination of oleanolic acid and ursolic acid by liquid chromatography tandem mass spectrometry. 2′-Carbonyl-piperazine rhodamine B was first designed and synthesized as the derivatization reagent, which was easily adsorbed onto the surface of Fe3O4/graphene oxide. Simultaneous derivatization and extraction of oleanolic acid and ursolic acid were performed on Fe3O4/graphene oxide. The permanent positive charge of the derivatization reagent significantly improved the ionization efficiencies. The limits of detection were 0.025 and 0.020 ng/mL for oleanolic acid and ursolic acid, respectively. The validated method was shown to be promising for sensitive, accurate, and simultaneous determination of oleanolic acid and ursolic acid. It was used for th...