Micellar liquid chromatography (MLC) is a simple well-established branch of high-performance liquid chromatography. The applications of MLC for the determination of numerous compounds in pharmaceutical formulations, biological samples, food, and environmental samples have been growing very rapidly. MLC technique has several advantages over other techniques, such as simultaneous separation of charged and uncharged solutes, rapid gradient capability, direct on-column injection of physiological fluids, unique separation selectivity, high reproducibility, robustness, enhanced luminescence detection, low cost, and safety. This review is devoted to the evaluation of the agreement of MLC with the principles of green chemistry which recently represents a universal trend. Also, it provides an overview on the basics of MLC, in addition to a survey of MLC methods published in the past five years for the assay of various compounds in different matrices.

A new, simple and sensitive spectrofluorimetric method has been developed for the determination of pregabalin (PG) in capsules. The method is based on the reaction between pregabalin and fluorescamine in borate buffer solution of pH 10 to give a highly fluorescent derivative that is measured at 487 nm after excitation at 390 nm. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. The fluorescence intensity concentration plot was rectilinear over the range of 0.01-0.3 µg mL⁻¹ with a lower detection limit of 0.0017 µg mL⁻¹ and limit of quantitation of 0.005 µg mL⁻¹. The developed method was successfully applied to the analysis of the drug in its commercial capsules. The mean percentage recovery of PG in its capsule was 99.93±1.24 (n = 3). Statistical comparison of the results with those of the comparison method revealed good agreement and proved that there was no significant difference in the accuracy and precision of the two methods. A proposed reaction pathway was postulated.

Isotope-coded derivatization (ICD) is used as a promising alternative approach to isotope internal standards in order to overcome matrix effects caused by coexisting substances that often occur while analyzing metabolites by LC-MS/MS. ICD introduces two different mass tags to every analyte via the use of heavy and light forms of the derivatization reagents. Herein, we report the first ICD approach for aldehydes that uses commercially available reagents avoiding the need for expensive and tedious multisteps synthetic procedures. The method is based on the reaction of the safe and stable derivatizing agent, 9,10-phenanthrenequinone, and the cheap and commercially available ICD reagent, 14 N/ 15 N-ammonium acetate, with aldehydes followed by LC/ESI + -MS/MS. Multiple reaction monitoring is done at the transitions m/z [M + H] + → m/z [Product ion A] and m/z [M + 2 + H] + → m/z [Product ion A + 2] for 14 N-and 15 N-labeled analytes, respectively. Among lipid peroxidation products, 4-hydroxy-2-nonenal (HNE) and 4-hydroxy-2-hexenal (HHE) are considered the most toxic produced aldehydes as they contain additional two reactive functional groups, the unsaturated bond and the hydroxyl group, besides the aldehyde one. Thus, they were chosen as representative analytes in this study. The developed method was able to detect HHE and HNE in human serum with very high sensitivity down to LOQ of 0.2 and 0.05 nM, respectively, employing an expedient salting out liquid−liquid extraction method. The developed method was able to differentiate between the levels of HHE and HNE in serum samples of healthy subjects and diabetic, rheumatic, and cardiac disorder patients.

A validated, simple and sensitive HPLC method was developed for the simultaneous determination of lipoperoxidation relevant reactive aldehydes; glyoxal (GO), acrolein (ACR), malondialdehyde (MDA) and 4-Hydroxy-2-nonenal (HNE) in human serum. The studied aldehydes were reacted with 2,2'-furil to form fluorescent difurylimidazole derivatives that were separated on respectively, with detection limits ranged from 0.030 to 0.11 nmol/mL. The % RSD of intra-day and inter-day precision didn't exceed 5.0% and 6.2%, respectively, and the accuracy (%found) ranged from 95.5 to 103%. The proposed method was applied for monitoring the four aldehydes in sera of healthy, diabetic and rheumatic human subjects with simple pretreatment steps and without interference from endogenous components. By virtue of its high sensitivity and accuracy, our method enabled detection of differences between analytes concentrations in sera of human subjects at different clinical conditions.