Sunscreen analysis

Voltammetric determination of organic UV filters by carbon paste electrodes modified with pyridinium-based ionic liquids

The rapid and sensitive voltammetric determination of organic UV filters benzophenone-3 (BP-3) and avobenzone (AVO) was performed by an ionic liquid carbon paste electrode (IL-CPE). Namely, the synthesized pyridinium-based ILs, 1-butyl-3-methylpyridinium chloride ([N-C4-3C1Py]Cl) and 1-ethoxyethyl-3-methylpyridinium chloride ([N-C2OC2-3C1Py]Cl) were compared as bulk CPE modifiers for BP-3 determination. [N-C4-3C1Py]Cl-CPE showed more favorable interactions with the target analyte, and it was tested for AVO determination, too. Cyclic voltammetric (CV) studies suggested that the irreversible electrode reaction is adsorption controlled in the case of both UV filters. Also, the square-wave adsorptive stripping voltammetric (SW-AdSV) method was optimized for quantifying selected UV filters. In the model solutions, the linear calibration curve was obtained by the SW-AdSV method in the concentration range from 0.05 to 0.89 μg mL-1 at pH 3.0 for BP-3 (Eacc = -0.7 V, tacc = 100 s), and from 0.05 to 1.77 μg mL-1 at pH 11.98 for AVO (Eacc = 0.2 V, tacc = 100 s). The evaluated limit of detection (LOD) was 0.015 μg mL-1 in both cases, while the relative standard deviation (RSD) was lower than 1.5%. The affordable IL-based voltammetric sensor fulfills the main requirements for application in real samples due to an adequate selectivity towards selected analytes in the presence of interferents usually found in swimming pool water. Therefore, the BP-3 and AVO were quantified in a swimming pool water matrix with good repeatability and recovery. The obtained results demonstrate an excellent potential of the IL-CPEs, especially of the [N-C4-3C1Py]Cl-CPE, for determining selected UV filters in various real samples.

Exposure to high-performance benzotriazole ultraviolet stabilizers: Advance in toxicological effects, environmental behaviors and remediation mechanism using in-silica methods

Benzotriazole ultraviolet stabilizers (BUVSs), as light stabilizers, have attracted widespread attention because of their easy migration in the environment and their acute toxicity and biological toxicity effects, such as immunotoxicity and hepatotoxicity. Accordingly, the treatment and remediation mechanisms of high-performance, environmentally friendly, and low human health risk BUVS substitutes were analyzed. Firstly, the weights and the comprehensive effect (CE) values of migration and toxicity of BUVSs were determined by Topsis assisted by the coefficient of variation (CV) method. From this, a three-dimensional quantitative structure activity relationship (3D-QSAR) model based on the CE values of the 13 BUVSs was constructed. Secondly, EPI software was used to predict the functionality and environmental friendliness of BUVS substitutes, and a partial least squares regression machine learning (ML-PLSR) model was used to analyze the mechanism. Then, ADMET (absorption, distribution, metabolism, excretion, toxicity), TOPKAT, and exposure dose models were used to evaluate the ecological and human health risks of BUVSs and their substitutes. Finally, the key charge information affecting the UV-326 substitutes was deduced by time dependent density functional theory (TDDFT). Using UV-326 as an example, 15 UV-326 substitutes with reduced CE values were designed (reductions of 2.61%-23.18%). Compared with ML-PLSR models of acute toxicity, immunotoxicity, and hepatotoxicity, it was found that the decrease of DM and Q_yy values and the increase of Q_zz value could further decrease the toxicity of the UV-326 substitutes. Ecological and human health risk assessment showed that the exposure risks of the six UV-326 substitutes were within acceptable limits. TDDFT showed that the change of electron distribution and electron excitation type were the key factors affecting the performance of the UV-326 substitutes, and a charge transfer excitation type was more conducive to obtaining high-performance, environmentally friendly UV-326 substitutes. This study aims to alleviate the toxic damage to the ecological environment and human health caused by BUVS exposure.

Lab-in-Syringe, a Useful Technique for the Analysis and Detection of Pollutants of Emerging Concern in Environmental and Food Samples

Lab-in-syringe is a new approach for the integration of various analytical extraction steps inside a syringe. Fully automated dispersive liquid-liquid microextraction is carried out in-syringe using a very simple instrumental setup. Dispersion is achieved by aspiration of the organic phase and then the watery phase into the syringe as rapidly as possible. After aggregation of the solvent droplets, the organic phase is pushed towards the detector allowing a highly sensitive spectrophotometric or fluorimetric detection. This technique is very useful not only for the preconcentration of analyte, but also for the elimination of their interferences. In this work, its application is described using solvents that are lighter and denser than water. The magnetically assisted variant and its coupling to different instruments has been also described with the aim of increasing the resolution of complex samples, especially useful for the determination of emerging contaminants.

Magnetic Nanoparticle-Based Dispersive Solid-Phase Microextraction of Three UV Blockers Prior to Their Determination by HPLC-DAD

The need for proper handling of environmental samples is significant, owing to their environmental effects on both humans and animals, as well as their immediate surroundings. In the current study, magnetic nanoparticle-based dispersive solid-phase microextraction was combined with high-performance liquid chromatography using a diode array as the detector (HPLC-DAD) for both the separation and determination of three different UV blockers, namely octocrylene, ethylhexyl methoxycinnamate, and avobenzone. The optimum conditions for the extraction were found to be as follows: Stearic acid magnetic nanoparticles (20 mg) as the sorbent, acetonitrile (100 µL) as the eluent, as well as a sample pH of 2.50, adsorption and desorption time of 1.0 min, with a 3.0 mL sample volume. The limits of detection were as low as 0.05 µg mL-1. The coefficient of determination (R2) was above 0.9950, while the percentages of relative recoveries (%RR) were between 81.2 and 112% for the three UV blockers from the environmental water samples and sunscreen products.

Investigating the exposure and impact of chemical UV filters on coral reef ecosystems: Review and research gap prioritization

Coral reefs are among the world's most productive and biologically diverse ecosystems. In recent decades, they have experienced an unparalleled decline resulting from various anthropogenically induced stressors. Ultraviolet (UV) filters found in personal care products, such as sunscreen, are chemical pollutants that are emerging as a growing toxic threat to reef organisms. In this study, a systematic literature review was conducted to (1) determine the current understanding of spatial distribution and the occurrence of UV filters exposed to the marine environment, (2) synthesize current ecotoxicological thresholds of relevant reef organisms under various UV-filter exposures, (3) identify research gaps related to both exposure and toxicity of UV filters in coral reef ecosystems. With gaps identified, a survey was developed and distributed to experts in the field representing academic, governmental, not-for-profit, and industry researchers in order to prioritize research gaps and inform future research efforts. The survey identified the need for better understanding of the impacts of co-stressors, long-term exposure, mixture, and degradation product exposure and realistic environmental conditions. Ultimately, this review will help guide priority research efforts to understand the risks of UV-filter exposure to coral reef ecosystems. Integr Environ Assess Manag 2021;17:967-981. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

[Simultaneous determination of 22 sunscreen agents in cosmetics by ultra-high-performance liquid chromatography using diode array detector]

A fast and simple ultra-high-performance liquid chromatography using diode array detector (UHPLC-DAD) technique has been developed for the simultaneous determination of 22 sunscreen agents (UV filters), viz. phenylbenzimidazole sulfonic acid (PBS), terephthalydene dicamphor sulfonic acid (TDS), benzophenone-4 (BZ4), camphor benzalkonium methosulfate (CBM), benzophenone-2 (BZ2), benzylidene camphor sulfonic acid (BCS), benzophenone-3 (BZ3), 3-benzylidene camphor (3BC), isoamyl p-methoxycinnamate (IMC), 4-methylbenzylidene camphor (MBC), diethylamino hydroxybenzoyl hexyl benzoate (DHHB), octocrylene (OCR), butyl methoxydibenzoyl methane (BDM), ethylhexyl dimethyl PABA (EDP), ethylhexyl methoxycinnamate (EMC), homosalate (HS), ethylhexyl salicylate (ES), diethylhexyl butamido triazone (DBT), ethylhexyl triazone (ET), drometrizole trisiloxane (DRT), methylene bis-benzotriazolyl tetramethylbutylphenol (MBP), and bis-ethylhexyloxyphenol methoxyphenyl triazine (EMT) in cosmetic products. Different parameters, such as column type, oven temperature, mobile phase composition, and detection wavelength, were studied. The best chromatographic separation was obtained under the following conditions: Poroshell 120 EC-C18 (100 mm×4.6 mm, 2.7 μm) column set at 25 ℃ and gradient acetonitrile-isopropanol-water (containing 50 mmol/L ammonium acetate and 0.05% (v/v) formic acid) as the mobile phase, pumped at a flow rate of 0.5 mL/min, with a wavelength of 311 nm. The proposed UHPLC-DAD technique provided separation of the 22 target sunscreen agents within 35 min, with the optimized sample pretreatment procedure below. First, samples were mixed thoroughly by adding 2 mL or 5 mL tetrahydrofuran, followed by vortex and dispersal. If the wax samples were still not homogenized completely, an ultrasonic dispersal protocol with heating to 50 ℃ was adopted. Second, the homogeneous samples were ultrasonically extracted with ethanol containing 0.1% (v/v) formic acid. The developed method showed good linear relationships, with correlation coefficients of no less than 0.998. Two kinds of samples with different matrix types were fortified at three levels. The average spiked recoveries of 22 UV filters ranged from 85.2% to 112.3%, with the relative standard deviations (RSDs) ranging from 0.5% to 6.5%. The limits of detection were between 0.7 and 64 mg/kg, and the limits of quantification ranged from 2.4 mg/kg to 215 mg/kg. Moreover, the stabilities of the mixed standard solutions at the levels of 2, 10, and 50 mg/L were tested. The stability results showed that drometrizole trisiloxane was stable for 12 h, while the others were stable for 36 h. The reliability of the developed method was demonstrated by applying it to 16 commercial sunscreen-containing cosmetic samples obtained from the Chinese market. The levels determined in this study agreed well with those of five commercial samples (such as emulsion and cream). The method developed was remarkably different from the standard method, which is mentioned in the Safety and Technical Standards for Cosmetics (2015 edition), especially in terms of mobile phase composition and extraction solvent. Compared to the standard method, this method bypassed the use of large amounts of corrosive solvents like tetrahydrofuran and perchloric acid, thus improving the extraction efficiency of low-polarity components like drometrizole trisiloxane, methylene bis-benzotriazolyl tetramethylbutylphenol, and bis-ethylhexyloxyphenol methoxyphenyl triazine, and the analytes were well separated with better stability. Benzophenone-2 was added to this method as another detection component. The good analytical features, as well as their environment-friendly characteristics, make the presented method suitable not only for routine analysis in cosmetics industries, but also as a candidate reference method for sunscreen analysis.

Benzophenone-3 degradation via UV/H2O2 and UV/persulfate reactions

The degradation of benzophenone-3 (BP3) in water via the UV/H₂O₂ and UV/persulfate (UV/PS) reactions was investigated. The degradation of BP3 exhibited pseudo-first-order kinetics in both reactions. The degradation efficiency of BP3 was higher in the UV/PS reaction than in the UV/H₂O₂ reaction. In both reactions, the observed rate constants (k_obs) of BP3 degradation were highest at pH 6 and increased linearly with increasing dosage of H₂O₂ and persulfate. The second-order rate constants of BP3 with •OH (k_{•OH_BP3}) and •SO₄^- (k_•SO4-_{_BP3}) were determined to be 1.09 (± 0.05) × 10¹⁰ and 1.67 (± 0.04) × 10⁹ M^-1 s^-1, respectively. The k_obs values of BP3 were affected by water components such as HCO₃^-, NO₃^-, Cl^-, and Br^- ions, as well as humic acid. Based on the identified transformation products (TPs), the degradation pathway of BP3 during both reactions was a hydroxylation reaction. The inhibition of bioluminescence in Vibrio fischeri due to BP3 and its TPs decreased more quickly in the UV/PS reaction than in the UV/H₂O₂ reaction. The results suggest that the UV/PS process is a better alternative to the UV/H₂O₂ process for removing BP3 and its toxicity in water.

Investigation of calcium silicate as a natural clay-based sunblock: Formulation and characterization

BACKGROUND

Sunlight exposure causes several types of health issues to humans, and in particular, it affects especially the skin. Among the most common harmful issues developed by UV exposure are erythema, pigmentation, and lesions in DNA, which may lead to cancer. These long-term effects can be minimized with the use of sunscreen.

OBJECTIVE

The use of commercial UV filters causes severe side effects such as skin allergy and whitening of the skin. Therefore, in this study the effectiveness of Ca₂ SiO₄ , a compound abundantly present in the soils of certain South Asian regions, has been the first time explored as UV filter. This compound leaves a low amount of white residue on the skin and is highly stable.

METHOD

The comparative study of a cosmetic formulation having 5% Ca₂ SiO₄ , and other formulations containing 5% TiO₂ and 5% ZnO as inorganic UV filters, was performed to evaluate the physical and chemical stability.

RESULT

The zeta potential and chemical stability of formulations containing these different UV filters were investigated by using UV-Vis spectroscopy, FTIR-ATR, and X-ray diffraction. Results indicated Ca₂ SiO₄ as a promising innovative UV filter with an SPF value of 37.94. One of the reasons is its low interaction with organic filter, that is, PABA, as compared to commercial ZnO and TiO₂ inorganic UV filters. Biological absorption in organs was studied by ICP-MS on model mice.

CONCLUSION

It also has a low photocatalytic activity; thus, formation of radicals is minimum. Moreover, Ca₂ SiO₄ showed a recognized ability to leave a low amount of white residue on the skin combined with great stability.

Rutile nano-bio-interactions mediate dissimilar intracellular destiny in human skin cells

The use of nanoparticles (NPs) in the healthcare market is growing exponentially, due to their unique physicochemical properties. Titanium dioxide nanoparticles (TiO₂ NPs) are used in the formulation of sunscreens, due to their photoprotective capacity, but interactions of these particles with skin cells on the nanoscale are still unexplored. In the present study we aimed to determine whether the initial nano-biological interactions, namely the formation of a nano-bio-complex (other than the protein corona), can predict rutile internalization and intracellular trafficking in primary human fibroblasts and keratinocytes. Results showed no significant effect of NPs on fibroblast and keratinocyte viability, but cell proliferation was possibly compromised due to nano-bio-interactions. The bio-complex formation is dependent upon the chemistry of the biological media and NPs' physicochemical properties, facilitating NP internalization and triggering autophagy in both cell types. For the first time, we observed that the intracellular traffic of NPs is different when comparing the two skin cell models, and we detected NPs within multivesicular bodies (MVBs) of keratinocytes. These structures grant selected input of molecules involved in the biogenesis of exosomes, responsible for cell communication and, potentially, structural equilibrium in human tissues. Nanoparticle-mediated alterations of exosome quality, quantity and function can be another major source of nanotoxicity.

Miniaturized Matrix Solid-Phase Dispersion for the Analysis of Ultraviolet Filters and Other Cosmetic Ingredients in Personal Care Products

A method based on micro-matrix solid-phase dispersion (μ-MSPD) followed by gas-chromatography tandem mass spectrometry (GC–MS/MS) was developed to analyze UV filters in personal care products. It is the first time that MSPD is employed to extract UV filters from cosmetics samples. This technique provides efficient and low-cost extractions, and allows performing extraction and clean-up in one step, which is one of their main advantages. The amount of sample employed was only 0.1 g and the extraction procedure was performed preparing the sample-sorbent column in a glass Pasteur pipette instead of the classic plastic columns in order to avoid plastizicer contamination. Factors affecting the process such as type of sorbent, and amount and type of elution solvent were studied by a factorial design. The method was validated and extended to other families of cosmetic ingredients such as fragrance allergens, preservatives, plasticizers and synthetic musks, including a total of 78 target analytes. Recovery studies in real sample at several concentration levels were also performed. Finally, the green extraction methodology was applied to the analysis of real cosmetic samples of different nature.

Screening and quantification of emerging contaminants in Periyar River, Kerala (India) by using high-resolution mass spectrometry (LC-Q-ToF-MS)

The presence of emerging contaminants (ECs) in different aquatic systems may contribute to hazardous effects on aquatic organisms and subsequently on human health. In the present work, liquid chromatography coupled to a quadrupole time of flight mass spectrometer (LC-Q-ToF-MS) was used to identify and quantify a series of ECs in Periyar River in Aluva region, Kerala, India. The water samples were pre concentrated using solid-phase extraction (SPE) prior to analysis. The compounds were probed in both positive and negative ionization mode using electro spray ionization (ESI). Method validations were performed for linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision (intraday and inter day). The ECs were quantified using standard calibration curve. The identified nine ECs include pharmaceuticals, personal care products, steroids, surfactants, and phthalate. A relatively high concentration was observed in the case of 2-dodecyl benzene sulfonic acid (1012 ng/l) and low concentration was observed for lignocaine (4.3 ng/l; since this is below LOQ, the value is only approximate). In addition, we have identified another 28 organic compounds using the technique of non-target analysis out of which seven compounds fall in the category of surfactants. Being the first report on ECs in Periyar River, the data is very important as this river is one of the biggest and important rivers of Kerala having several purification units for drinking water in the province.

Electron microscopic investigation and elemental analysis of titanium dioxide in sun lotion

OBJECTIVE

The objective of this research was to determine the size, shape and aggregation of titanium dioxide (TiO₂ ) particles which are used in sun lotion as UV-blocker.

METHODS

Overall, six sunscreens from various suppliers and two reference substances were analysed by electron microscopy (EM) techniques in combination with energy dispersive X-ray spectroscopy (EDS). Because of a high fat content in sun lotion, it was impossible to visualize the TiO₂ particles without previous EM sample preparation. Different defatting methods for TiO₂ from sun screens were tested. A novel sample preparation method was developed which allowed the characterization of TiO₂ particles with the help of EM and EDS.

RESULTS

Aggregates of titanium dioxide with the size of primary particles varying between 15 and 40 nm were observed only in five products. In the sun lotion with the highest SPF, only few small aggregates were found. In the sun screen with the lowest SPF, the largest aggregates of TiO₂ particles were detected with sizes up to 1.6 μm. In one of the sun lotions, neither TiO₂ nor ZnO was found in spite of the labelling. Instead, approx. 500 nm large diamond-shaped particles were observed. These particles are composed of an organic material as only carbon was detected by EDS.

CONCLUSION

A novel defatting method for sample preparation of titanium dioxide nanoparticles used in sun cosmetics was developed. This method was applied to six different sun lotions with SPF between 30 and 50+. TiO₂ particles were found in only five sunscreens. The sizes of the primary particles were below 100 nm and, according to the EU Cosmetic Regulation, have to be listed on the package with the term 'nano'.

A review of organic UV-filters in wastewater treatment plants

UV-filters are a group of compounds which have been massively used in the past years due to the recent concerns with sunburns, premature skin ageing and the risk of developing skin cancer, related to sun exposure. At the moment, these compounds have been identified by the scientific community as emerging pollutants, due to their persistence in the environment, potential to accumulate in biota and potential threat as endocrine disruptors. At some point, the majority of sunscreens will find their way into wastewater (due to bathing and washing activities) and because wastewater treatment plants (WWTPs) are not able to remove and/or degrade them, consequently they find their way into rivers, lakes and ocean, so it is not surprising that UV-filters are found in the environment. Therefore, wastewater treatment plants should be the focus of the scientific community aiming to better understand the fate of the UV-filters and develop new technologies to remove them from wastewater and sludge. This review, aims to provide the current state of the art in the occurrence and fate of UV-filters in wastewater treatment plants and how the technologies that are being used are successfully removing these compounds from both wastewater and sludge.

Are sunscreens a new environmental risk associated with coastal tourism?

The world coastal-zone population and coastal tourism are expected to grow during this century. Associated with that, there will be an increase in the use of sunscreens and cosmetics with UV-filters in their formulation, which will make coastal regions worldwide susceptible to the impact of these cosmetics. Recent investigations indicate that organic and inorganic UV-filters, as well as many other components that are constituents of the sunscreens, reach the marine environment--directly as a consequence of water recreational activities and/or indirectly from wastewater treatment plants (WWTP) effluents. Toxicity of organic and inorganic UV filters has been demonstrated in aquatic organism. UV-filters inhibit growth in marine phytoplankton and tend to bioaccumulate in the food webs. These findings together with coastal tourism data records highlight the potential risk that the increasing use of these cosmetics would have in coastal marine areas. Nevertheless, future investigations into distribution, residence time, aging, partitioning and speciation of their main components and by-products in the water column, persistence, accumulation and toxicity in the trophic chain, are needed to understand the magnitude and real impact of these emerging pollutants in the marine system.

Advances in analytical methods and occurrence of organic UV-filters in the environment--A review

UV-filters are a group of compounds designed mainly to protect skin against UVA and UVB radiation, but they are also included in plastics, furniture, etc., to protect products from light damage. Their massive use in sunscreens for skin protection has been increasing due to the awareness of the chronic and acute effects of UV radiation. Some organic UV-filters have raised significant concerns in the past few years for their continuous usage, persistent input and potential threat to ecological environment and human health. UV-filters end up in wastewater and because wastewater treatment plants are not efficient in removing them, lipophilic compounds tend to sorb onto sludge and hydrophilics end up in river water, contaminating the existing biota. To better understand the risk associated with UV-filters in the environment a thorough review regarding their physicochemical properties, toxicity and environmental degradation, analytical methods and their occurrence was conducted. Higher UV-filter concentrations were found in rivers, reaching 0.3mg/L for the most studied family, the benzophenone derivatives. Concentrations in the ng to μg/L range were also detected for the p-aminobenzoic acid, cinnamate, crylene and benzoyl methane derivatives in lake and sea water. Although at lower levels (few ng/L), UV-filters were also found in tap and groundwater. Swimming pool water is also a sink for UV-filters and its chlorine by-products, at the μg/L range, highlighting the benzophenone and benzimidazole derivatives. Soils and sediments are not frequently studied, but concentrations in the μg/L range have already been found especially for the benzophenone and crylene derivatives. Aquatic biota is frequently studied and UV-filters are found in the ng/g-dw range with higher values for fish and mussels. It has been concluded that more information regarding UV-filter degradation studies both in water and sediments is necessary and environmental occurrences should be monitored more frequently and deeply.

Occurrence of eight UV filters in beaches of Gran Canaria (Canary Islands). An approach to environmental risk assessment

Due to the growing concern about human health effects of ultraviolet (UV) radiation, the use of UV filters has increased in recent decades. Unfortunately, some common UV filters are bioaccumulated in aquatic organisms and show a potential for estrogenic activity. The aim of the present study is to determine the presence of some UV filters in the coastal waters of six beaches around Gran Canaria Island as consequence of recreational seaside activities. Eight commonly used UV filters: benzophenone-3 (BP-3), octocrylene (OC), octyl-dimethyl-PABA (OD-PABA), ethylhexyl methoxy cinnamate (EHMC), homosalate (HMS), butyl methoxydibenzoyl methane (BMDBM), 4-methylbenzylidene camphor (4-MBC) and diethylamino hydroxybenzoyl hexyl benzoate (DHHB), were monitored and, with the exception of OD-PABA, all were detected in the samples collected. 99% of the samples showed some UV filters and concentration levels reached up to 3316.7 ng/L for BP-3. Environmental risk assessment (ERA) approach showed risk quotients (RQ) higher than 10, which means that there is a significant potential for adverse effects, for 4-MBC and EHMC for those samples with highest levels of UV filters.

Fabrication and application of zinc-zinc oxide nanosheets coating on an etched stainless steel wire as a selective solid-phase microextraction fiber

A novel zinc-zinc oxide (Zn-ZnO) nanosheets coating was directly fabricated on an etched stainless steel wire substrate as solid-phase microextraction (SPME) fiber via previous electrodeposition of robust Zn coating. The scanning electron micrograph of the Zn-ZnO nanosheets coated fiber exhibits a flower-like nanostructure with high surface area. The SPME performance of as-fabricated fiber was investigated for the concentration and determination of polycyclic aromatic hydrocarbons, phthalates and ultraviolet (UV) filters coupled to high performance liquid chromatography with UV detection (HPLC-UV). It was found that the Zn-ZnO nanosheets coating exhibited high extraction capability, good selectivity and rapid mass transfer for some UV filters. The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the calibration graphs were linear over the range of 0.1-200μgL(-1). The limits of detection of the proposed method were 0.052-0.084μgL(-1) (S/N=3). The single fiber repeatability varied from 5.18% to 7.56% and the fiber-to-fiber reproducibility ranged from 6.74% to 8.83% for the extraction of spiked water with 50μgL(-1) UV filters (n=5). The established SPME-HPLC-UV method was successfully applied to the selective concentration and sensitive determination of target UV filters from real environmental water samples with recoveries from 85.8% to 105% at the spiking level of 10μgL(-1) and 30μgL(-1). The relative standard deviations were below 9.7%.

Self-assembly of alkyldithiols on a novel dendritic silver nanostructure electrodeposited on a stainless steel wire as a fiber coating for solid-phase microextraction

A facile and efficient electrodeposition approach for the controllable preparation of dendritic silver nanostructure was developed on an etched stainless steel (ESS) wire.

Fabrication of host–guest UV-blocking materials by intercalation of fluorescent anions into layered double hydroxides

A host–guest UV-blocking material was obtained by the intercalation of a fluorescent whitening agent into the layered double hydroxide, which can absorb and convert UV light into visible fluorescence emission instead of thermal radiation.

In situ anodic growth of rod-like TiO2 coating on a Ti wire as a selective solid-phase microextraction fiber

A novel rod-like TiO₂ based SPME coating was directly fabricated by in situ anodization of Ti wire (Fig. 1). It has larger surface area and longer service time for sensitive determination of ultraviolet filters in environmental water samples.

Development and Validation of a Stability Indicating RP-HPLC Method for the Determination of Two Sun Protection Factors (Koptrizon and Tinosorb S) in Topical Pharmaceutical Formulations Using Experimental Designs

A novel, simple, validated stability indicating HPLC method was developed for determination of Koptrizon and Tinosorb S. Stability indicating power of the method was established by forced degradation study. The chromatographic separation was achieved with Waters X Bridge column, by using mobile phase consisting of a mixture of acetonitrile : tetrahydrofuran : water (38 : 38 : 24, v/v/v). The method fulfilled validation criteria and was shown to be sensitive, with limits of detection (LOD) and quantitation (LOQ) of 0.024 and 0.08 μg  for Koptrizon and 0.048 and 0.16 μg  for Tinosorb S, respectively. The developed method is validated for parameters like precision, accuracy, linearity, solution stability, specificity, and ruggedness as per ICH norms. Design expert with ANOVA software with linear model was applied and a 23 full factorial design was employed to estimate the model coefficients and also to check the robustness of the method. Results of the two-level full factorial design, 23 with 10 runs including two-centre-point analysis based on the variance analysis (ANOVA), demonstrated that all three factors, as well as the interactions between retention time of Koptrizon, Tinosorb S, and USP plate count for Koptrizon, are statistically significant.