Novel Salt-Assisted Liquid-Liquid Microextraction Technique for Environmental, Food, and Biological Samples Analysis Applications: A Review

Rapid green analytical methodology for simultaneous monitoring of nitrosamines and semi-volatile organic compounds in water and human urine samples

Nitrosamines and semi-volatile organic compounds (SVOCs) are carcinogenic contaminants in water and biological matrices. Conventional analytical methods often struggle to detect trace concentrations due to poor extraction efficacies. This study presents a novel, low-cost, in-syringe-assisted fast extraction cum cleanup technique coupled with GC-FID for monitoring four nitrosamines and two SVOCs in drinking water and human urine samples to measure the contamination and exposure levels. This extraction protocol combines a novel green in-syringe liquid-liquid extraction step using dimethyl carbonate as the green extraction solvent, coupled with a semi-automated solid-phase extraction cleanup process. Then, the final extractant is analyzed using gas chromatography-flame ionization detection (GC-FID) for monitoring. The method demonstrated excellent linearity (R2 > 0.998) between 1.5 and 500 ng mL⁻1 for all six target compounds. Detection limits ranged from 1.0 to 2.0 ng mL⁻1. Extraction recoveries were between 87 and 105% for both urine samples and water samples. Intra-day and inter-day precision were below 9% RSD. The blue applicability grade index evaluation scored 70.0, indicating good practical applicability. The developed analytical protocol offers a sensitive, accurate, low-cost, rapid, and environmentally friendly method for simultaneously quantifying multiple nitrosamines and SVOCs in environmental and human samples. Its performance characteristics and sustainability metrics suggest the potential for broad application in monitoring and exposure studies.

Polar licit and illicit ingredients in dietary supplements: chemometric optimization of extraction and HILIC-MS/MS analysis

Many dietary supplements claim the ability to enhance sports performance and to improve the fitness of the consumers. Occasionally, along with legal ingredients, illicit compounds may be added without being labelled, leading to unintended doping. Hence, the aim of this study was to develop an analytical method to determine a set of 12 polar (logDpH=7 from -2.0 to +0.3) compounds including diuretics, stimulants, β2-agonists, methylxanthines, and sweeteners. Hydrophilic interaction liquid chromatography was chosen as separation strategy, coupled with tandem mass spectrometry. The instrumental method was optimized using a two-step design of experiments (DoE). Firstly, a Plackett-Burman (PB) DoE was performed to identify the more influencing variables affecting peak areas and chromatographic resolution among temperature, water percentage in the mobile phase, and flow rate, as well as type and concentration of buffers. Secondly, a D-optimal DoE was set, considering only the most significant variables from the PB-DoE results, achieving a deeper understanding of the retention mechanism. Sample processing by salt-assisted liquid-liquid extraction was studied through DoE as well, and the whole method showed recoveries in the range 40-107% and procedural precision ≤11% for all analytes. Finally, it was applied to real samples, in which the four methylxanthines and two artificial sweeteners were detected and quantified in the range of 0.02-192 mg g-1. These values were compared to the quantities declared on the DS labels, when possible. Furthermore, a sequence of MS/MS scans allowed detection of a signal in one of the samples, structurally similar to the β2-agonist clenbuterol.

A rapid and sensitive analytical methodology for the simultaneous biomonitoring of two direct oral anticoagulant drugs and their major metabolites in thromboembolic disordered patients samples for clinical evaluations

Apixaban and dabigatran are the two major direct oral anticoagulant drugs to treat thromboembolic disordered patients. Increasing the clinical application for the thromboembolic disorder and monitoring the concentrations of apixaban, dabigatran, and their metabolites are essential in most clinical circumstances. In this work, we developed a rapid analytical methodology comprising of vortex-assisted salt-enhanced liquid-liquid microextraction technique coupled with UHPLC-MS/MS for the extraction and simultaneous determination of two major direct oral anticoagulant drugs (apixaban, dabigatran), and their two major metabolites from plasma, serum, and urine samples of patients. The developed method was optimized with various procedural steps and validated to study the analytical merits. The developed method yielded a good detection limit of 0.01 ∼ 0.37 ng/mL, 0.01 ∼ 0.32 ng/ml, and 0.01 ∼ 0.27 ng/mL for four target analytes in the plasma, serum, and urine matrices. Moreover, extraction recoveries ranged from 85.11 - 113.57% (for plasma), 89.63 - 110.47% (for serum), and 87.44 -106.79% (for urine samples) with 8.78% RSD. In addition, the method exhibited good R2 values of 0.999 for all four target analytes, and the specificity and carryover study revealed no carryover effect from the UHPLC-MS/MS system for determining the apixaban, dabigatran, and their metabolites. Due to the above advantages, the developed analytical technique was applied to examine 11 real-time clinical patients' samples, and the observed results were satisfactory for all three different sample matrices. Therefore, this analytical method can be applied for biomonitoring apixaban, dabigatran, and their two major metabolites with high sensitivity in a short time for various clinical applications.

Salt-Induced Homogeneous Liquid–Liquid Microextraction of Piroxicam and Meloxicam from Human Urine Prior to Their Determination by HPLC-DAD

A salt-induced homogeneous liquid–liquid microextraction (SI-HLLME) protocol combined with high-performance liquid chromatography–diode array detection is presented for the first time for the determination of piroxicam and meloxicam in human urine. The main parameters affecting the performance of the sample preparation protocol were optimized by means of a two-step experimental design (i.e., 2-level fractional factorial design and Box–Behnken design). Following its optimization, the proposed method was thoroughly validated in terms of the total error concept in order to take into consideration the random and systematic errors. For the target analytes, accuracy profiles were constructed, and they were used as graphical decision-making tools. In all cases, the β-expectation tolerance intervals complied with the acceptance criteria of ±15%, proving that 95% of future results will fall within the defined bias limits. The limits of detection were 0.02 μg mL−1 and 0.03 μg mL−1 for piroxicam and meloxicam, respectively. The relative standard deviations were lower than 4.4% in all cases, and the mean relative biases ranged between −5.7 and 3.4% for both drugs. The proposed scheme is simple and rapid, while it is characterized by high sample throughput. Moreover, SI-HLLME requires reduced sample and reagent consumption, according to the requirements of Green Analytical Chemistry.