Determination of Benzophenones in Water and Cosmetics Samples: A Comparison of Solid-Phase Extraction and Microextraction by Packed Sorbent Methods

Benzophenones (BPs) are extensively used in a wide variety of cosmetic products and other materials (e.g., textiles or plastics) to avoid damaging effects of UV radiation. In the present work, we compared two extraction methods for the determination of BPs, namely, 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3) and 2,2-dihydroxy-4-methoxybenzophenone (BP-8), in water and cosmetics samples. The following extraction methods were used for the research: solid-phase extraction (SPE) and microextraction by packed sorbent (MEPS), whereas analysis was performed by gas chromatography with mass spectrometric detection. A comparison between the methods indicates that the MEPS technique(s) can be reliably used for analysis of BPs (sunscreen residue) in water samples and cosmetic samples with satisfactory results. This microextraction technique is cheap, easy, quick to implement, and consumes small amounts of solvents. On the other hand, the main advantage of the SPE method are low detection limits for the determination of BPs in water samples, i.e., from 0.034 to 0.067 µg L−1, while, for the MEPS method, LODs were at the level of 1.8–3.2 µg L−1. For both methods, the recoveries of BPs were 96–107% and 44–70% for water and cosmetics samples, respectively. The presented methods are suitable for use in cosmetics quality control and environmental pollution assessment.

Overcoming challenges associated with the bioanalysis of cysteine-conjugated metabolites in the presence of antibody–drug conjugates

Aim: Investigations have shown that for the antibody–drug conjugate (ADC) belantamab mafodotin, concentrations of the cysteine-conjugated metabolite, Cys-mcMMAF, were overestimated in the presence of the ADC during sample processing when utilizing a historical SPE method. Results: A new assay was developed utilizing an acidic protein precipitation to remove the ADC early in the extraction process, thus eliminating the risk of overestimating Cys-mcMMAF in the presence of belantamab mafodotin. In vitro experiments demonstrated a linear relationship between the concentration of belantamab mafodotin and the release of Cys-mcMMAF. Extensive stability assessments were performed to cover storage of study samples. Conclusion: This work emphasized the critical importance of understanding the performance of a bioanalytical method for free toxic payload in the presence of the ADC.

Purification of Curcuminoids from Natural Deep Eutectic Solvents (NADES) Matrices Using Chromatography-Based Separation Methods

Curcuminoids can be successfully extracted from Curcuma zedoaria using natural deep eutectic solvents (NADES) as extraction solvents. However, a mixture of extracted curcuminoids, NADES, and impurities from C. zedoaria was obtained as a slurry at the end of the extraction process. Therefore, further separation and purification were required to obtain the extracted compound in high purity. Herein, two purification methods based on classical column chromatography (CCC) and solid-phase extraction (SPE), were evaluated for the purification of curcuminoids from NADES matrices after extraction. Choline chloride–malic acid–water (CCMA–H2O) and choline chloride–citric acid–water (CCCA–H2O) in the molar ratio of 1:1:18 were selected as NADES matrices due to their high solubility and stabilization capability for curcuminoids. Ethanol-conditioned silica gel (60–200 µm) was applied as the bed resin for CCC, and a C18 cartridge was used for SPE. Acetonitrile/0.1% acetic acid, water/0.1% acetic acid, and iso-propanol/0.1% acetic acid were used as mobile phases for CCC. For SPE, methanol/0.05% acetic acid and water/0.05% acetic acid were applied in the conditioning step, water/0.05% acetic acid in the washing step, and methanol/acetonitrile (1:1) in the eluting step. The SPE method produced higher recovery of curcuminoids from the CCCA–H2O and CCMA–H2O matrices (75.27% and 73.40%, respectively) compared to CCC (51.9% and 61.0%, respectively). After removing the NADES constituents from the crude extract of curcuminoids, recrystallization was attempted.

Solid Phase Extraction Method for the Determination of Atrazine and Cyanazine in Water Samples

Triazine is one of the herbicides group that is widely used in agriculture that acts as an inhibitor for the growth of unwanted weeds in plants. The use of this herbicide on plants is absorbed by the soil and flows into a nearby water system. This research focused on two types of triazines, namely atrazine and cyanazine. This research aims to extract this type of triazine herbicides and to determine their concentration in water samples. It was quantified by using gas chromatography-electron capture detector (GC-ECD). Solid phase extraction (SPE) method was applied to extract herbicides from water samples. The results indicate that all the samples contained atrazine and cyanazine. Studies in the range of 0.5 - 25 mg/L achieved good linearity with good correlation of determination, r2 value of 0.9922 - 0.9982 mg/L. Relative standard deviations (RSD) for triplicate analysis of the samples were less than 10.0%. The limit of detection (LODs) and limit of quantification (LOQs) of cyanazine and atrazine were found, ranging from 3.33 – 6.67 μg/L and 11.09 – 20.10 μg/L, respectively. The recoveries of the triazine herbicides studied in water samples ranged from 82.5% to 107.6%. The developed method exhibited excellent clean-up capability and was successfully applied for determining triazine herbicide residues in water samples.

Comparison of ozonation removal for PPCPs in secondary treated sewage by microbubble generator and ejector

This study analyzed residues of PPCPs in secondary treated sewage water, and their amount eliminated by ozonation processes. A microbubble nozzle and ejector were used to dissolve ozone. To consider a low concentration of PPCPs, a SPE method was performed on samples prior to the analysis. The concentration of dissolved ozone was 4.00 mg/L in the microbubble and 2.49 mg/L in the ejector. To examine elimination trends, the experiment was also performed at a low concentration of ozone, 1/10 of its original concentration. The maximum elimination rate on average was 93.0% in the ejector, higher than that in the microbubble (90.1%), but 16 PPCPs were found to show a relatively high elimination rate in the microbubble, higher than the ejector. Elimination trends with respect to time were distinguished based on inflection point, and 11 PPCPs were concentrated on the latter half of the microbubble after the inflection point at the low concentration of ozone, which was compared to other cases. In the source water, concentrations of 2 PPCPs were higher than the reference toxic concentration based on the QSAR model, but after treatment, only bezafibrate was over the value when the ejector with low ozone injection concentration was applied.

Digital counting of single semiconducting polymer nanoparticles for the detection of alkaline phosphatase

The single particle enumeration (SPE) method is proposed for the detection of alkaline phosphatase (ALP) based on the fluorescence suppression by polydopamine shell on the surface of semiconducting polymer nanoparticles (SPNs).

Trace carbonyl analysis in water samples by integrating magnetic molecular imprinting and capillary electrophoresis

By integrating MMIPs-SPE method and CE, the enrichment of carbonyls-DNPH derivatives with simultaneous removal of the surplus derivative agent 2,4-DNPH can be achieved.