A cross-sectional study on metoprolol concentrations in various biological samples and their inter-correlations.

BACKGROUND: Concentrations of metoprolol in exhaled breath condensate (EBC) have not been investigated. Herein, we aim to determine the metoprolol levels in EBC, plasma, and urine samples. METHODS: Biological samples were collected from 39 patients receiving metoprolol. Metoprolol was determined using liquid chromatography mass spectrometery. The obtained metoprolol levels in biological fluids were investigated for possible inter-correlations. RESULTS: Acceptable linearity was obtained with coefficient of determinations equal to 0.9998, 0.9941, and 0.9963 for EBC, plasma, and urine samples, respectively. The calibration curves were linear in the ranges of 0.6-500, 0.4-500, and 0.7-10,000 µg·L- 1 regarding EBC, plasma, and urine samples, respectively. The detection and quantification limits were (0.18, 0.12, and 0.21 µg·L- 1) and (0.60, 0.40, and 0.70 µg·L- 1) for EBC, plasma, and urine samples, respectively. The relative standard deviations for the intra- and inter-day replications were obtained between 5.2 and 6.1 and 3.3-4.6%, respectively. The obtained mean metoprolol levels in EBC, plasma, and urine samples of 39 patients were 5.35, 70.76, and 1943.1 µg·L- 1. There were correlations between daily dose and plasma and urinary concentrations of metoprolol in the investigated samples, whereas no significant correlation was observed for daily dose and EBC levels. The correlation among plasma-urine levels was significant, however, the non-significant correlation was obtained between plasma and EBC concentrations. CONCLUSION: Metoprolol levels varied widely due to the metabolic pattern of the Azeri population, different dosages received by the patients, formulation effects, age, sex, and interactions with the co-administered drugs. A poor correlation of EBC-plasma concentrations and a significant correlation of plasma-urine concentrations were observed. Further investigations are required to provide the updated services to personalized medicine departments.

A modified quick-easy-cheap-effective-rugged-and-safe method involving carbon nano-onions-based dispersive solid-phase extraction and dispersive liquid-liquid microextraction for pesticides from grapes.

A combination of modified quick easy cheap effective rugged and safe extraction approach with carbon nano-onions-based dispersive solid-phase extraction and dispersive liquid-liquid microextraction was developed for the extraction of several pesticides (diazinon, chlorpyrifos, tebuconazole, deltamethrin, permethrin, haloxyfop-methyl, penconazole, and cyhalothrin) from grape before their analysis by gas chromatography-flame ionization detection. In the extraction approach, an aliquot of grape sample is chopped and after separating its juice, the pesticides that remained in the refuse are extracted by the quick, easy, cheap, effective, rugged, and safe extraction method. The obtained acetonitrile phase is mixed with juice and the analytes are extracted by the carbon nano-onions-based dispersive solid-phase extraction. The analytes are concentrated using the microextraction procedure to obtain high enrichment factors. The results showed low limits of detection (0.5-1.6 ng/g) and quantification (1.8-5.4 ng/g) with satisfactory linearity of the calibration curves (determination coefficient, r2 ≥ 0.994). The precision of the developed method expressed as relative standard deviations was good (≤7.2%). The method provided high enrichment factors (350-410) and extraction recoveries (70-82%). Finally, seven grape samples were analyzed successfully.

pH-induced homogeneous liquid-liquid microextraction method based on new switchable deep eutectic solvent for the extraction of three antiepileptic drugs from breast milk.

Aim: A pH-induced homogeneous liquid-liquid microextraction (HLLME) using a new switchable deep eutectic solvent has been used for the extraction of three antiepileptic drugs from breast milk samples. Methodology: This method is based on phase separation by changing pH. An ammonia solution and a phosphocholine chloride: hexanoic acid: p-aminophenol deep eutectic solvents were used as the phase separation agent and extraction solvent, respectively. Results: Significant factors were studied and the detection limits and enrichment factors were in the ranges of 0.009-0.19 ng ml-1 and 182-212 for the analytes, respectively. Also, linear ranges were wide (0.63-500 ng ml-1) and the method precision was acceptable. Conclusion: The introduced method was successfully applied for the determination of the analyte concentrations in breast milk samples.

Monolithic mixed matrix membrane based on polyethersulfone/functionalized MWCNTs nanocomposite as an SPME fiber: Application to extract chlorophenols from human urine and serum samples followed by GC-ECD.

A monolithic mixed matrix membrane of functionalized multi-walled carbon nanotubes-polyethersulfone (MWCNT/PES) was prepared in a non-covalent approach and employed as an SPME fiber for extraction of chlorophenols (CPs). The proposed extraction method was followed by GC-ECD to determine the analytes. The influencing factors on the extraction efficiency such as pH, ionic strength, extraction and desorption temperature and time were studied. Under the selected conditions, calibration curves were linear over a wide concentration range from 0.005 to 1000 µgL-1 (r2 > 0.9961) for target analytes. In addition, the limits of detection (LOD) of the method were obtained in the range of 0.3-30 ng L-1. The relative standard deviation (RSD) for single fiber repeatability (n = 5) is from 1.4 to 4.6%. Fiber-to-fiber repeatability (n = 3) was also evaluated and the RSD is in the range of 1.3-6.3%. Applications of proposed fiber for extraction of CPs from the headspace of urine and serum samples were successfully investigated. The relative recovery in the biological samples spiked with different levels of CPs were in the range of 91.6-102.5%.

Introduction of coiled solid phase microextraction fiber coated by mesoporous silica/cetyltrimethylammonium bromide for ultra-trace environmental analysis.

In this study, a tiny coiled cupper wire as a novel solid phase microextraction (SPME) fiber was coated with mesoporous silica/cetyltrimethylammonium bromide (MCM-41/CTAB) as an adsorbent by electrochemically assisted self-assembly method and used for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) as model analytes prior to chromatographic determination. Deposition of MCM-41/CTAB on the coiled SPME (C-SPME) fiber resulted in easily controlled and reproducible SPME coatings. Non-calcined MCM-41/CTAB on C-SPME plays a key role in the adsorption of PAHs. Under the optimized experimental conditions, low detection limits (36-1220pgL-1), and wide linear dynamic ranges (R2>0.98) were achieved in the range of 0.25-25,000, 0.12-15,000, 0.56-32,000, 4.1-100,000ngL-1 for phenanthrene, anthracene, fluoranthene and pyrene respectively. The reusability of proposed fiber as well as relative standard deviations for repetitive determination of the target analytes was evaluated. The proposed method was successfully applied for determination of PAHs in several real samples.

Simultaneous derivatization and air-assisted liquid-liquid microextraction of some parabens in personal care products and their determination by GC with flame ionization detection.

A simultaneous derivatization/air-assisted liquid-liquid microextraction technique has been developed for the sample pretreatment of some parabens in aqueous samples. The analytes were derivatized and extracted simultaneously by a fast reaction/extraction with butylchloroformate (derivatization agent/extraction solvent) from the aqueous samples and then analyzed by GC with flame ionization detection. The effect of catalyst type and volume, derivatization agent/extraction solvent volume, ionic strength of aqueous solution, pH, numbers of extraction, aqueous sample volume, etc. on the method efficiency was investigated. Calibration graphs were linear in the range of 2-5000 µg/L with squared correlation coefficients >0.990. Enhancement factors and enrichment factors ranged from 1535 to 1941 and 268 to 343, respectively. Detection limits were obtained in the range of 0.41-0.62 µg/L. The RSDs for the extraction and determination of 250 µg/L of each paraben were <4.9% (n = 6). In this method, the derivatization agent and extraction solvent were the same and there is no need for a dispersive solvent, which is common in a traditional dispersive liquid-liquid microextraction technique. Furthermore, the sample preparation time is very short.