Solid-phase extraction (SPE) coupled with capillary electrophoresis (CE) for the determination of macrolide antibiotics (azithromycin, clarithromycin, roxithromycin, tylosin) and tiamulin in water ...samples was described in this article. These compounds were extracted with different types of sorbents ( Oasis HLB, C18, C8, SDB, and Strata-X) and different masses of sorbents (60 mg, 200 mg, and 500 mg) using different organic solvents (methanol, ethanol, and acetonitrile) and different pH values of water samples (pH 7.00, 8.00, and 9.00). It was found that the highest extraction efficiency of the studied compounds was obtained with 200 mg/3 mL C18 cartridges with methanol as eluent at pH 9.00 of the water sample. The developed SPE-CE method for macrolide antibiotics and tiamulin was validated for linearity, precision, repeatability, the limit of detection (
), the limit of quantification (
), and recovery. Good linearity was obtained in the range of 0.3–30 mg L
depending on the drug, with correlation coefficients higher than 0.9958 in all cases except clarithromycin (0.9873). Expanded measurement uncertainties were calculated for each pharmaceutical, accounting for 20.31 % (azithromycin), 38.33 % (tiamulin), 28.95 % (clarithromycin), 26.99 % (roxithromycin), and 21.09 % (tiamulin). Uncertainties associated with precision and calibration curves contributed the most to the combined measurement uncertainty. The method was successfully applied to the analysis of production waste-water from the pharmaceutical industry.
Albendazole is a broad-spectrum anthelmintic drug effective against gastrointestinal parasites in humans and animals. Despite the fact that it has been detected in environment (water, sediment and ...soil), there is no information on its fate in the environment. So, in order to understand the sorption process of albendazole in environment, the sorption mechanism and kinetic properties were investigated through sorption equilibrium and sorption rate experiments. For that purpose, batch sorption of albendazole on five sediment samples and five soil samples from Croatia's region with different physico-chemical properties was investigated. Except physico-chemical properties of used environmental solid samples, the effects of various parameters such as contact time, initial concentration, ionic strength and pH on the albendazole sorption were studied. The Kd parameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Langmuir sorption models were applied to describe the equilibrium isotherms. The estimated Kd values varied from 29.438 to 104.43 mLg−1 at 0.01 M CaCl2 and for natural pH value of albendazole solution (pH 6.6). Experimental data showed that the best agreement was obtained with the linear model (R2 > 0.99), while the rate of albendazole sorption is the best described with the kinetic model of pseudo-second-order. Obtained results point to a medium or even strong sorption of albendazole for soil or sediment particles, which is particularly dependent on the proportion of organic matter, pH, copper and zinc in them.
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•The sorption of albendazole was studied in five soil and five sediment from Croatia.•Equilibrium data were tested using linear, Freundlich and Langmuir sorption isotherms.•Kd values indicated that albendazole is moderately mobile/immobile in environment.•pH, ionic strength and properties of sediment/soil have great impact on ALBA sorption.
In the development of bioanalytical LC-MS methods for the determination of drugs in plasma samples in a clinical setting, adequate sample preparation is of utmost importance. The main goals are to ...achieve the selective extraction of the analytes of interest and attain thorough matrix removal while retaining acceptable ecological properties, cost-effectiveness, and high throughput. Solid-phase extraction (SPE) offers a versatile range of options, from the selection of an appropriate sorbent to the optimisation of the washing and elution conditions. In this work, the first SPE method for the simultaneous extraction of six anticancer drugs used in novel therapeutic combinations for advanced breast cancer treatment—palbociclib, ribociclib, abemaciclib, anastrozole, letrozole, and fulvestrant—was developed. The following sorbent chemistries were tested: octylsilyl (C8), octadecylsilyl (C18), hydrophilic–lipophilic balance (HLB), mixed-mode cation-exchange (MCX and X-C), and mixed-mode weak cation-exchange (WCX), with different corresponding elution solvents. The samples were analysed using LC-MS/MS, with a phenyl column (150 × 4.6 mm, 2.5 μm). The best extraction recoveries (≥92.3%) of all analytes were obtained with the C8 phase, using methanol as the elution solvent. The optimised method was validated in the clinically relevant ranges, showing adequate precision (inter-day RSD ≤ 14.3%) and accuracy (inter-day bias −12.7–13.5%). Finally, its applicability was successfully proven by the analysis of samples from breast cancer patients.
Ciprofloxacin is a fluoroquinolone antibiotic that is effective in vitro against Gram-positive and Gram-negative microorganisms. Since the ciprofloxacin, along with other pharmaceuticals, can ...influence the environment, the goal of this study was to examine the possibility of ciprofloxacin removal from water using biosorbents, an unconventional and cheaper subclass of adsorbents. For this purpose, the effect of ionic strength, pH, temperature, different mass of the used biosorbent, and physical-chemical characteristics of biosorbents on ciprofloxacin sorption was investigated. Biosorbents, used in this study, are the various waste products like maple leaves (ML), tangerine peel (TP), and tomato waste (TW) (seeds and peel). Sorption parameters of ciprofloxacin were determined by linear, Freundlich, and Dubinin-Radushkevich isotherms. The highest value of the sorption coefficient,
K
d
, shows the maple leaves, while the minimum achieves a sample of tangerine peel. These values correspond to the analysis and distribution of pore size, where the tangerine peel sample has the lowest specific surface area. The obtained results indicated the potential of investigated biosorbents to sorption of ciprofloxacin, which ultimately can contribute to environmental protection and the disposal of waste products.
In this study, equilibrium isotherms, kinetics and thermodynamics of ciprofloxacin on seven sediments in a batch sorption process were examined. The effects of contact time, initial ciprofloxacin ...concentration, temperature and ionic strength on the sorption process were studied. The
K
d
parameter from linear sorption model was determined by linear regression analysis, while the Freundlich and Dubinin–Radushkevich (D–R) sorption models were applied to describe the equilibrium isotherms by linear and nonlinear methods. The estimated
K
d
values varied from 171 to 37,347 mL/g. The obtained values of
E
(free energy estimated from D-R isotherm model) were between 3.51 and 8.64 kJ/mol, which indicated a physical nature of ciprofloxacin sorption on studied sediments. According to obtained
n
values as measure of intensity of sorption estimate from Freundlich isotherm model (from 0.69 to 1.442), ciprofloxacin sorption on sediments can be categorized from poor to moderately difficult sorption characteristics. Kinetics data were best fitted by the pseudo-second-order model (
R
2
> 0.999). Thermodynamic parameters including the Gibbs free energy (Δ
G
°), enthalpy (Δ
H
°) and entropy (
Δ
S°) were calculated to estimate the nature of ciprofloxacin sorption. Results suggested that sorption on sediments was a spontaneous exothermic process.
Memantine is a pharmaceutical used to treat memory loss, one of the main symptoms of dementia and Alzheimer’s disease. The use of memantine is expected to continue to grow due to the increasing ...proportion of the elderly population worldwide. The aim of this work was to conduct a comprehensive study on the behaviour of memantine in the environment and the possibilities of its removal from wastewater. Abiotic elimination processes (hydrolysis, photolysis and sorption) of memantine in the environment were investigated. Results showed that memantine is stable in the environment and easily leached from river sediment. Therefore, further investigation was focused on memantine removal by advanced oxidation processes that would prevent its release into the environment. For photolytic and photocatalytic degradation of memantine, ultraviolet (UV) lamps with the predominant radiation wavelengths of 365 nm (UV-A) and 254/185 nm (UV-C) were used as a source of light. TiO2 in the form of a nanostructured film deposited on the borosilicate glass wall of the reactor was used for photocatalytic experiments. Photodegradation of memantine followed pseudo-first-order kinetics. The half-life of photocatalytic degradation by UV-A light was much higher (46.3 min) than the half-life obtained by UV-C light (3.9 min). Processes degradation efficiencies and evaluation of kinetic constants were based on the results of HPLC-MS/MS analyses, which also enable the identification of memantine oxidation products. The acute toxicity of the reaction mixture during the oxidation was evaluated by monitoring the inhibition of the luminescence of Vibrio fischeri bacteria. The results showed that memantine and its oxidation products were not harmful to Vibrio fischeri.
Sample preparation is a very important and essential step in environmental analysis. This article presents an overview of extraction methods for environmental samples, focusing especially on ...pharmaceuticals as there is great concern about them as pollutants.
The use of powdered activated carbon (PAC) as an absorbent has become a promising option to upgrade wastewater treatment plants (WWTPs) that were not designed to remove pharmaceuticals. However, PAC ...adsorption mechanisms are not yet fully understood, especially with regard to the nature of the wastewater. In this study, we tested the adsorption of three pharmaceuticals, namely diclofenac, sulfamethoxazole and trimethoprim, onto PAC under four different water matrices: ultra-pure water, humic acid solution, effluent and mixed liquor from a real WWTP. The adsorption affinity was defined primarily by the pharmaceutical physicochemical properties (charge and hydrophobicity), with better results obtained for trimethoprim, followed by diclofenac and sulfamethoxazole. In ultra-pure water, the results show that all pharmaceuticals followed pseudo-second order kinetics, and they were limited by a boundary layer effect on the surface of the adsorbent. Depending on the water matrix and compound, the PAC capacity and the adsorption process varied accordingly. The higher adsorption capacity was observed for diclofenac and sulfamethoxazole in humic acid solution (Langmuir isotherm,
> 0.98), whereas better results were obtained for trimethoprim in the WWTP effluent. Adsorption in mixed liquor (Freundlich isotherm,
> 0.94) was limited, presumably due to its complex nature and the presence of suspended solids.
An analytical method for multi-class pharmaceuticals determination in wastewater has been developed and validated. Target compounds were: sulfonamides (sulfadiazine, sulfaguanidine, sulfamethazine, ...sulfamethoxazole), fluoroquinolones (ciprofloxacin, enrofloxacin, norfloxacin), diaminopyrimidine (trimethoprim), anaesthetic (procaine), anthelmintic (praziquantel and febantel), and macrolide (roxithromycin). The method involves pre-concentration and clean-up by solid-phase extraction (SPE) using Strata-X extraction cartridges at pH 4.0. Target analytes were identified and quantitatively determined by liquid chromatography–tandem mass spectrometry using multiple reaction monitoring (MRM). Recoveries were higher than 50% with relative standard deviation (RSD) below 18.3% for three concentrations. Only for sulfaguanidine was low recovery obtained. Matrix effect was evaluated using matrix-matched standards. The method detection limit (MDL) was between 0.5 and 5 ng L
−1
in spiked water samples. The precision of the method, calculated as relative standard deviation, ranged from 0.5 to 2.0% and from 1.4 to 8.3 for intra-day and inter-day analysis, respectively. The described analytical method was used for determination of pharmaceuticals in effluent wastewaters from the pharmaceutical industry.
Tomato waste was studied as a low-cost biosorbent for the removal of five pharmaceuticals (dexamethasone, febantel, procaine, praziquantel, and tylosin) from water. Tomato waste was characterized ...chemically and microstructurally before and after simulated sorption. Sorption performance was interpreted as a function of the initial pharmaceuticals concentration, temperature, and physicochemical properties of the tomato waste. The linear, Freundlich, and Dubinin–Radushkevich (D-R) isotherms were used to describe the experimental results at different temperatures (298, 303, and 308 K). Thermodynamic parameters such as standard free energy (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were determined. Negative values of ΔG° in the temperature range of 298–308 K strongly indicate the spontaneous nature of the biosorption process. In addition, the values of ΔH° for the biosorption of dexamethasone, procaine, praziquantel, and tylosin on tomato waste were negative, indicating exothermic processes, while the positive value for febantel indicated an endothermic process. The kinetic data were analyzed using (i) kinetic models to determine the kinetic parameters (Lagergren’s pseudo-first order and Ho’s pseudo-second order) and (ii) adsorption–diffusion models to the describe transport mechanisms of pharmaceuticals from aqueous solution onto tomato waste as adsorbent (Weber–Morris intraparticle diffusion and Boyd film diffusion models).
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