Homogeneous liquid phase microextraction using hydrophilic media for the determination of fluoroquinolones in human urine using HPLC-FLD

Analysis of glipizide and pravastatin sodium drug molecules at trace level by using magnetic solid phase extraction and HPLC-DAD system

An easy applicable and selective sample preparation technique has been developed for trace and simultaneously analysis of Glipizide (GLP) and Pravastatin (PST) molecules in biological matrices based on magnetic solid phase extraction (MSPE) and high-performance liquid chromatography (HPLC). A new magnetic adsorbent including Fe3O4@TEOS-Melamine has been synthetized and characterized for extraction studies. Experimental variables of MSPE were examined and optimized step by step such as pH, adsorption and desorption conditions, time effect, etc. Simultaneous HPLC analysis of GLP and PST molecules was performed by isocratic elution of a mixture of acetonitrile: phosphate buffer (pH:3.0, 0.02 M) (35:65) with flow rate 1.0 mL min-1. Analytical signals obtained from DAD detector were recorder in 238 and 226 nm for PST and GLP, respectively. The limit of detections (LOD) for proposed method were 3.17 ng mL-1 for PST and 3.03 ng mL-1 for GLP molecules. Consequently, accuracy and precision of developed method were tested by means of recovery tests in synthetic urine and saliva samples. RSD % values were lower than 6.1 % and recovery values were in the range of 98.5-103.3 % for both molecules.

Application of zwitterionic ionic liquid-based capsule phase microextraction for the HPLC-UV determination of doxycycline in human urine samples

Herein, we describe the utilization of an ionic liquid (IL)/Carbowax 20 M-functionalized sol-gel sorbent for the capsule phase microextraction of doxycycline in authentic human urine samples. This green sample preparation method combines stirring and filtration in a single, standalone sample preparation device, streamlining the sample preparation process. Additionally, it provides rapid extraction kinetics and high extraction efficiency. The experimental conditions (i.e. sorbent type, sample pH and volume, extraction time, ionic strength, elution solvent, and volume) affecting the extraction efficiency of the analyte were studied and optimized. The method was linear in the range of 0.1 - 5.0 μg/mL with a coefficient of determination higher than 0.995. The achieved LOD was found to be 0.02 μg/mL while the lower limit of quantitation (LLOQ) was 0.1 μg/mL. The IL/Carbowax 20 M-functionalized microextraction capsules were reusable at least 30 times for urine samples. The relative recoveries (% RR) ranged between 93.4 - 115.9 % while the precision (expressed as % RSD) was better than 8.1 % in all cases. The robustness of the microextraction procedure and the instrumental HPLC method were separately investigated using Plackett-Burman experimental designs. The analytical protocol demonstrated cost-effectiveness, ease of handling, and speed, leading to increased sample throughput. The green character of the developed method was evaluated using the Green Analytical Procedure Index (GAPI) and Blue Applicability Grade Index (BAGI). Finally, the method's applicability was demonstrated by analyzing authentic human urine samples after oral administration of a doxycycline-containing pharmaceutical formulation.

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.

Salting-out homogeneous liquid-liquid microextraction for the determination of azole drugs in human urine: Validation using total error concept

A salting-out homogeneous liquid-liquid microextraction was proposed for the quantification of four azole drugs in human urine prior to high-performance liquid chromatography analysis. The procedure involved the mixing of the sample with acetonitrile in appropriate volumes followed by the addition of sodium sulfate solution in order to facilitate phase separation. The parameters influencing the extraction performance were studied and optimized using a two-step experimental design. The analytical procedure was thoroughly validated using the accuracy profiles as a graphical decision-making tool. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±15% meaning that 95% of future results will be included in the defined bias limits. The limits of detection of the procedure were satisfactory, ranging between 0.01 and 0.03 μg/mL. The mean analytical bias in the spiking levels was satisfactory and ranged between -10.3 and 4.2% while the relative standard deviation was lower than 5.6%. Monte-Carlo simulations followed by capability analysis were employed to investigate the ruggedness of the sample preparation protocol. The developed method offers advantages compared to previously reported approaches for the same type of analysis including extraction efficiency and scaling down of the sample volume and extraction time.