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An analytical method for the determination of the controversial UV filter 3-(4′-methylbenzylidene)camphor (MBC) and its metabolite 3-(4′-carboxybenzylidene)camphor (CBC) in human semen is presented. The method is based on the simultaneous hydrolysis of phase II conjugates and protein precipitation, followed by solid-phase extraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) detection. The proposed method was validated by analyzing spiked analyte-free human semen samples. Matrix-matched calibration using an analyte-free semen pool was employed. Satisfactory recoveries (92–114%) were obtained using this calibration methodology, thus showing the accuracy of the proposed method. The limits of detection were at the low μg L−1level (1 and 2 μg L−1for MBC and CBC, respectively) and the intra- and inter-day precision, expressed as relative standard deviation, were in the range of 6–9% and 7–14%, respectively, depending on the analyte and the concentration level. The method was finally applied to the analysis of semen samples from two volunteers who topically applied a laboratory-made sunscreen cream containing MBC. Similar kinetic profiles performed during 72 hours were obtained for both volunteers. From this study it can be assumed that more than three days is necessary to completely metabolize or eject this UV filter.

An analytical method for the determination of eight fat-soluble ultraviolet (UV) filters in beach sand samples is presented for the first time. The method is based on a leaching process of the target compounds from sand samples using vortex mixer agitation and further centrifugation, followed by dispersive liquid–liquid microextraction (DLLME) of the supernatant and gas chromatography-mass spectrometry (GC-MS) analysis of the DLLME extract. The variables involved in the leaching and in the DLLME processes were studied to provide the best enrichment factors. In the first case, the leaching solvent type and volume, and the vortex mixer agitation time were studied. In the case of the DLLME, the type and volume of both disperser and extraction solvent and the influence of the pH and the ionic strength of the supporting aqueous solution were studied. Under the selected conditions, the method was successfully validated showing good linearity (R2> 0.995), method limits of detection at the pg g−1level, enrichment factors in the range of 8 to 50 (depending on the analyte) and good intra- and inter-day precision. No significant matrix effects were found, thus external calibration can be used. However, internal calibration was recommended to improve the repeatability in both the DLLME and the GC-injection. Moreover, in order to correct losses during the leaching process, the surrogate was added to the samples before the leaching step. The validated method was successfully applied to the analysis of several beach sand samples of different origin.

The UV filter 3-(4′-methylbenzylidene)camphor (MBC) is a common ingredient in sunscreen cosmetic products. However, different in vitroand in vivostudies suggest that MBC can cause endocrine disrupting effects. This report focuses on the development of an analytical method based on solid-phase extraction (SPE) prior to liquid chromatography tandem mass spectrometry (LC-MS/MS) for the determination of MBC and its main phase I metabolite, named 3-(4′-carboxybenzylidene)camphor (CBC), in urine from users of sunscreen cosmetic products containing MBC. The formation of phase II metabolites (i.e., glucuronide and sulphate conjugates) was also considered by carrying out an enzymatic hydrolysis of the urine samples. The standard addition calibration method was used to quantify the target analytes in order to correct the matrix effects observed. In this way, statistically accurate results were obtained when the developed SPE-LC-MS/MS method was applied to the analysis of fortified analytes-free urine samples. The limits of detection were 6 ± 2 ng mL−1for MBC and 6 ± 1 ng mL−1for CBC, and the intra- and inter-day variability of the method, expressed as relative standard deviation, were in the range of 1.3–2.0% and 4.5–7.7%, respectively, depending on the analyte. The analytical method was satisfactorily applied to the analysis of real urine samples from a volunteer that was subjected to repeated applications of a sunscreen cosmetic containing MBC, showing that the major contribution to the excretion of MBC corresponded to the glucuronide conjugated species of CBC. Furthermore, the second main phase I metabolite of MBC, named 3-(4′-carboxybenzylidene)hydroxycamphor (CBC-OH), which also predominates in its glucuronide conjugate species in urine samples, was identified and detected.

Ascorbic acid (AA), also known as vitamin C, is a very popular skin‐whitening agent used in cosmetics. However, the use of AA (and also its sodium or magnesium salts) in cosmetic products is limited owing to its labile oxidative properties. In order to avoid its early degradation, different derivatives have been designed, such as ascorbyl phosphate (APH; as magnesium or sodium salts) and ascorbyl palmitate (AP), and more recently the ascorbyl glucoside (AG). Bearing in mind that all these chemicals in skin‐whitening cosmetic products must be determined in order to control the efficacy of such products, this paper focuses on developing a wide‐ranging LC analytical method able to determine the above‐mentioned compounds simultaneously in cosmetic products. The chromatographic variables were studied and selected in order to achieve the total separation and subsequent determination of all the analytes involved. Thus, an octadecylsilica (C18) stationary phase and a mobile phase gradient of ethanol: 50 mM phosphate buffer at different pHs (containing 0.1 M NaCl) were used. Detection was carried out with a UV/visible spectrometry detector set at different wavelengths. The LOD ranged from 2 to 6 μg/mL depending on the analyte. The proposed method was validated by analysing a laboratory‐made and six commercial skin‐whitening cosmetic samples. The method allows any mixture of the four skin‐whitening agents studied to be both separated at good resolution and determined without interferences from samples, and moreover it does not require the use of either highly toxic organic solvents or hazardous chemicals.

Near‐critical carbon dioxide extraction of four UV filters used as sunscreens in lipsticks and makeup formulations is reported. Extraction parameters were optimized. Efficient recoveries were obtained after 15 min of dynamic extraction with a 80:20 CO2/ethanol mixture at 300 atm and 54°C, using a 1.8 mL/min flow rate. Extracts were collected in ethanol, and appropriately diluted with ethanol and 1% acetic acid to obtain a 70:30 v/v ethanol/1% acetic acid solution. The four UV filters were determined by LC with gradient elution using ethanol/1% acetic acid as mobile phase. The accuracy of the analytical procedure was estimated by comparing the results with those obtained by methods based on classical extraction. The proposed method only requires the use of CO2, ethanol and acetic acid avoiding the use of more toxic organic solvents, thus it could be considered as both operator and environment friendly.

The polyphenols determined are: (+)‐catechin, (–)‐epicatechin, rutin, quercetin andtrans‐resveratrol. Suitable conditions of supercritical fluid extraction were established using ethanol as a modifier of the polarity solvent (supercritical carbon dioxide). Final extraction conditions were: 20% v/v ethanol, 60°C, 250 bars and flow rate 2 mL/min. Static step time and dynamic step time were established using a selected grape skin sample. The extract was collected in water; the more polar polyphenols ((+)‐catechin and (–)‐epicatechin) remain in solution but rutin, quercetin and trans‐resveratrol precipitate in this medium, thereby the solution of the extracted polyphenols was filtered. (+)‐Catechin and (–)‐epicatechin were determined in the liquid fraction, while the solid fraction, containing rutin, quercetin andtrans‐resveratrol, was solved with ethanol/H2O (40:60). HPLC determination was carried out at C18 stationary phase, with ethanol/water/acetic acid as mobile phases and UV‐visible diode array detection. Due to the significant differences between the polarity of the polyphenols, two different mobile phases were used. An ethanol/water/acetic acid (5:93:2) mobile phase was used to determine (+)‐catechin (280 nm) and (–)‐epicatechin (280 nm). On the other hand, rutin (254 nm), quercetin (254 nm) andtrans‐resveratrol (306 nm) were resolved using ethanol/water/acetic acid (40:58:2) as mobile phase. Instrumental parameters were optimised and analytical parameters obtained. The analytical method was validated and applied to five different varieties of Vitis viniferafrom the geographical area of Valencia.

Abstract. A sequential injection method is proposed for spectrophotometric determination of p-aminobenzoic acid (PABA) in cosmetic formulations. The method is based on diazotization of the analyte, coupling with 8-hydroxyquinoline, and the subsequent formation of a colored product. The experimental conditions used (coupling reagent, sandwich arrangement, volumes aspirated, propulsion flow rate, reaction coil length) were studied. Response of the sequential injection method were linearly dependent on concentrations up to 25 µg mL^-1 and the detection limit was 2 µg mL^-1. Throughput was 51 measurements per hour and a complete cycle, including three measurement per sample and a washing step, resulted in a sample throughput of 13.8 h^-1. Sunscreen formulations containing PABA were analyzed by the proposed method and validated by use of an HPLC procedure. The two methods gave comparable results. Yields ranged between 97-103% and good precision (RSD between 2 and 6%) was obtained. The accuracy, speed, and selectivity of the method make it suitable for safe application for quality-control of final products.

An inductively coupled plasma mass spectrometry (ICP-MS) procedure has been developed for the determination of major elements, such as Mg, Na, K, Ca and Fe, minor elements, such as Al, Cr, Mn, Cu, Zn, Se, Sr, Br and Rb, and trace elements, such as Li, Ti, Ni, As, I, Ba, Pb, Sc, V, Co, Y, Zr, Mo, Sn, Cs, Ga, Nb, Pd, Cd, Sb, Hf, W, Hg, Tl, Th and U, in wines. The results obtained for Na, Mg, Al, Mn, Fe, Co, Zn, Rb and Cs were compared with those found by neutron activation analysis (NAA). Two ICP-MS calibration methodologies were used and results evaluated from spike recovery studies from which an average recovery of 102±20% was found for quantitative mode measurements. Multi-determination, using Be, Ge, In and Bi for the calibration of the ICP-MS sensitivity in the whole mass range and Rh as the internal standard, provided fast and accurate results, whereas the quantitative mode, using a series of external standard solutions, needs more time and consumes more reagent.

A procedure was developed for the spectrophotometric determination of cholestanol in sediments based on its extraction with chloroform–methanol (2 + 1 v/v), dissolution of the extracts, after preconcentration, in pH 7.0 buffer-saturated toluene containing 10–3Mp-anisidine and enzymatic determination in non-aqueous media using a bienzymic reactor consisting of 1 mg of cholesterol oxidase and 1 mg of horseradish peroxidase non-covalently co-immobilized on controlled pore glass beads. A limit of detection of 2.0 × 10–6M was obtained under the optimum experimental conditions and recoveries of 95–118% were obtained in the analysis of water and beach sediment samples spiked with cholestanol at concentration levels of 0.4–1.0 mg g–1. This method can also be employed for the determination of cholesterol in sediment extracts, the analytical sensitivity for cholestanol being half that for cholesterol, and studies were carried out in order to determine accurately both compounds in the same sample.

The literature on the application of the slurry technique to biological materials is reviewed. It is obvious from the various applications that the most frequently employed atomization method for slurry analysis in biological materials is electrothermal atomization using either graphite tube or platform atomizers. The slurry technique is particularly useful when certified reference materials are not available and when the standard addition method is to be avoided. The literature survey revealed that this technique compares favourably with other methods for the determination of trace metals in biological materials.

Abstract: The applications of supercritical fluid chromatography to the analysis of drugs have been carefully revised from the literature compiled in the Analytical Abstracts until March 1994. Easy-to-read tables provide useful information about the state-of-the-art and possibilities offered by SFC in pharmaceutical analysis. The tables comprise extensive data about samples analyzed, pharmaceutical principles determined, solvents used and sample quantity injected, supercritical fluids and modifiers employed, injection system, instrumentation, experimental conditions for chromatographic separations (density, pressure, flow, temperature), characteristics of columns employed (type, support, length, diameter, particle film thickness, stationary phase), detectors, type of restrictors, and also some analytical features of the methods developed (such as retention time, resolution, sensitivity, limit of detection and relative standard deviation).

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