Determination of Alkylphenols Originated from Alkylphenol Ethoxylates by Cleavage Treatment Combined with GC-MS

A chemical cleavage technique was developed for the determination of alkylphenol ethoxylates (APEOs) in environmental samples involving the conversion of APEOs to alkylphenols (APs). Aluminum triiodide (AlI₃) and trimethylsilyl iodide were selected as cleavage reagents and the former was found to be highly reactive and suitable. With AlI₃ as cleavage reagent, nonylphenol ethoxylates (NPEOs) and octylphenol ethoxylates (OPEOs) were equivalently converted to the corresponding origins—nonylphenol (NP) and octylphenol (OP), which were detected by gas chromatography—mass spectrometry (GC-MS). The cleavage process was completed under refluxing condition. Water and methanol influenced the cleavage reaction significantly and should be removed prior to the cleavage reaction. The analytical approach was applied for the estimation of APEOs contents in wastewater by normalizing to APs and presented satisfactory recovery and reproducibility. This cleavage technique provides a common and reliable means to assess the environmental significance of samples contaminated by APEOs based on the presence of APs.     

Determination of chlormequat and mepiquat in pear,tomato, and wheat flour using on-line solid-phase extraction (Prospekt) coupled with liquid chromatography-electrospray ionization tandem mass spectrometry

A new methodology based on pressurized liquid extraction (PLE) followed by LC-MS is presented for the simultaneous and unequivocal determination of alkylphenol ethoxylates (APEOs) and their degradation products, alkylphenols (APs) and alkylphenoxy carboxylates (APECs), in sediment samples. The protocol, applicable to a full range of APEO oligomers and degradation products, permits the sensitive and selective determination of APEOs (nEO = 1-15), APECs (nEO = 0-1) and APs at low ppb levels (LODs = 1-5 microg/kg) in sediment samples. Optimization of the operational parameters of PLE clearly demonstrates that significant thermal losses of APs occur during extraction at elevated temperatures. The loss of octylphenol (OP) at 100 degrees C was 61.2% and of nonylphenol (NP) 40.0%, whereas other compounds were completely recovered. Thus, to avoid losses due to the volatility of alkylphenols, a low extraction temperature should be applied. The conditions that gave the best results for all target compounds were as follows: extraction solvent mixture, methanol-acetone (1:1, v/v); temperature, 50 degrees C; pressure, 1500 p.s.i.; two static cycles. Using PLE and a subsequent clean-up with solid-phase extraction (SPE), the simultaneous extraction of APEOs, APs and APECs from sediment samples was achieved yielding recoveries >70% and producing low MS background noise. The developed methodology was applied on a routine basis to the analysis of alkylphenolic compounds in sediment samples. APEOs and their persistent degradation products were detected in significant concentrations in sediments from Portuguese rivers, especially at sites situated in the proximity of industrial plants (mainly the textile industry). The total concentration of alkylphenolic compounds (APEOs+APs+APECs) ranged from 155 to 2400 microg/kg. Of all the alkylphenolic compounds, NP comprised 40 to 50% with concentrations up to 1172 microg/kg.     

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.     

超高效液相色谱-线性离子阱/静电场轨道阱高分辨质谱快速筛查化妆品中的24种激素

建立了超高效液相色谱-线性离子阱/静电场轨道阱组合式高分辨质谱联用（UPLC-LTQ/Orbitrap MS）快速筛查、定性识别化妆品中24种激素的分析方法。不同剂型的化妆品样品经甲醇超声提取,用Waters ACQUITY UPLC BEH C18色谱柱（50 mm×2.1 mm,1.7 μm）分离,以乙腈和0.1%（v/v）甲酸水溶液为流动相进行梯度洗脱。通过静电场轨道阱全扫描得到激素化合物的准分子离子的精确质量数,实现对化妆品中激素的快速筛查;再以保留时间和数据依赖扫描（data dependent scan）模式获得的子离子质谱图进行定性确证。24种激素化合物的质量准确度误差小于3×10^-6（3 ppm）;线性良好,相关系数大于0.99;检出限≤10 μg/kg（S/N=3）,能满足实际化妆品样品的分析要求。应用该方法对不同剂型的50余种化妆品样品进行筛查分析,结果良好。该方法是化妆品中激素快速筛查、定性识别的有效方法。     

Nitro musks in cosmetic products—determination by headspace solid-phase microextraction and gas chromatography with atomic-emission detection

Summary The combination of headspace solid-phase microextraction with atomic-emission detection enables highly selective and sensitive determination of itro musk compounds in cosmetic products. Sample preparation is considerably simplified; there is no solvent extraction step. Enrichment is influenced by the type and amount of cosmetic product investigated. The lowest amount giving well detectable peaks is 1 mg musk compound per kg sample. Calibration curves obtained from spiked solutions of selected reference cosmetics in water show very good linearity. Relative standard deviations of peak areas from repeated measurements are usually <10%. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

Determination of Phenolic Endocrine Disruptors in Cosmetics by High-Performance Liquid Chromatography Mass Spectrometry

An analytical method for the simultaneous determination of bisphenol A, 4-t-octylphenol, 4-n-octylphenol, and 4-n-nonylphenol in cosmetic samples has been developed. These compounds have toxic effects on human health as they have shown to produce endocrine disrupting properties. Therefore, their presence in cosmetics should be avoided according to the current European Regulations on cosmetic products. The method is based on high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS) detection. Standard addition calibration was used to avoid matrix effects. The limits of detection values ranged between 7 and 15?ng?mL^?1 (threefold of the residual standard deviation of regression lines). The proposed method was validated, and good recovery (90–106%) and repeatability values (2.7–8.2%) were obtained. Finally, the method was successfully applied to ten commercially available cosmetic samples. The good analytical features of the proposed method make it useful to carry out the quality control of cosmetic products and raw materials to assure the safety of users.     

Development of a solid-phase microextraction gas chromatography with microelectron-capture detection method for the determination of 5-bromo-5-nitro-1,3-dioxane in rinse-off cosmetics

5-Bromo-5-nitro-1,3-dioxane (bronidox) is a bromine-containing preservative often used in rinse-off cosmetics but also subjected to several restrictions according to the European Cosmetic Products Regulation. Thus, as a part of a quality control procedure, analytical methods for the determination of this compound in different types of cosmetics are required. In the present work, a solvent-free and simple methodology based on solid-phase microextraction (SPME) followed by gas chromatography with microelectron capture detection (GC-μECD) has been developed and validated for the determination of bronidox in cosmetic samples such as shampoos, body cleansers or facial exfoliants. As far as we know, this is the first application of SPME to this preservative. Negative matrix effects due to the complexity of the studied samples were reduced by dilution with ultrapure water. The influence of several factors on the SPME procedure such as fiber coating, extraction temperature, salt addition (NaCl) and sampling mode has been assessed by performing a 2⁴-factorial design. After optimization, the recommended procedure was established as follows: direct solid-phase microextraction (DSPME), using a PDMS/DVB coating, of 10 mL of diluted cosmetic with 20% NaCl, at room temperature, under stirring for 30 min. Using these suggested extraction conditions, linear calibration could be achieved, with limits of detection (LOD) and quantification (LOQ) well below the maximum authorized concentration (0.1%) established by the European legislation. Relative standard deviations (RSD) lower than 10% were obtained for both within a day and among days precision. The method was applied to diverse types of formulations spiked with bronidox at different concentration levels (0.008–0.10%); these samples were quantified by external calibration and satisfactory recoveries (≥70%) were obtained in all cases. Finally, the SPME–GC-μECD methodology was applied to the analysis of several cosmetics labeled or not as containing bronidox. The presence of this preservative in some of these samples was confirmed by GC–MS.     

Determination of alkylphenols and alkylphenol polyethoxylates by reversed-phase high-performance liquid chromatography and solid-phase extraction

A simple, accurate and reproducible reversed-phase high-performance liquid chromatography (HPLC) method was developed for the separation and characterisation of alkylphenols (APs) and alkylphenol polyethoxylates (APEOs), using a C18 octadecyl silica (ODS) column. APs and each APEO oligomer were separated successfully within a reasonable time without gradient elution. An excellent resolution was obtained, even for mixtures of APs and low EO number APEOs, which are otherwise difficult to separate using conventional normal-phase HPLC methods. This method, combined with solid-phase extraction, was highly applicable for the simultaneous determination of alkylphenols and alkylphenol ethoxylates in real samples.     

凝胶渗透色谱净化-气相色谱-串联质谱法同时测定不同配方体系化妆品中7种二甲基环硅氧烷

鉴于当前化妆品中二甲基环硅氧烷的添加乱象,以及关于二甲基环硅氧烷在化妆品中安全风险评价的研究也未有实质性进展,因此建立适合不同配方体系化妆品中二甲基环硅氧烷的测定方法具有一定的理论和现实意义。基于此,建立了凝胶渗透色谱净化结合气相色谱-串联质谱测定不同配方体系化妆品中7种二甲基环硅氧烷的方法。方法采用乙酸乙酯-环己烷(1∶1, v/v)提取,凝胶渗透色谱净化,通过DB-5ms色谱柱(30.0 m×0.25 mm×0.25 μm)分离和气相色谱-串联质谱选择反应监测(SRM)模式进行确证和检测,以正十六烷为内标物内标法定量。分别对内标物、提取溶剂和净化方式的选择进行了优化。在最终确立的条件下,7种二甲基环硅氧烷在0.05~1.0 mg/L范围内线性良好,相关系数为0.994~0.998;方法的检出限(LOD, S/N=3)和定量限(LOQ, S/N=10)分别为0.04~0.08 mg/kg和0.12~0.24 mg/kg;针对不同配方体系的化妆品基质,进行了低、中、高3个添加水平的加标回收试验,目标物的加标回收率为85.3%~108.8%,相对标准偏差(RSD)为3.1%~9.4%。该方法操作简便,灵敏度高,重复性好,能够满足不同配方体系化妆品中7种二甲基环硅氧烷的测定要求。采用所建立的方法对市面上的化妆品进行检测,八甲基环四硅氧烷(D4)和十甲基环五硅氧烷(D5)均有不同程度的检出。该方法的建立将为我国化妆品中二甲基环硅氧烷的质量监督检查提供技术依据,有利于保障化妆品的安全,同时也为后续化妆品中二甲基环硅氧烷的健康安全风险评价提供了技术支撑。     

Direct determination of mercury in cosmetic samples by isotope dilution inductively coupled plasma mass spectrometry after dissolution with formic acid

A new method was proposed for the accurate determination of mercury in cosmetic samples based on isotopic dilution (ID)-photochemical vapor generation (PVG)-inductively coupled plasma mass spectrometry (ICP MS) measurement. Cosmetic samples were directly dissolved in formic acid solution and subsequently subjected to PVG for the reduction of mercury into vapor species following by ICP MS detection. Therefore, the risks of analyte contamination and loss were avoided. Highly enriched ²⁰¹Hg isotopic spike is added to cosmetics and the isotope ratios of ²⁰¹Hg/²⁰²Hg were measured for the quantitation of mercury. With ID calibration, the influences originating from sample matrixes for the determination of mercury in cosmetic samples have been efficiently eliminated. The effects of several experimental parameters, such as the concentration of the formic acid, and the flow rates of carrier gas and sample were investigated. The method provided good reproducibility and the detection limits were found to be 0.6 pg mL⁻¹. Finally, the developed method was successfully applied for the determination of mercury in six cosmetic samples and a spike test was performed to verify the accuracy of the method.     

Environmentally friendly LC for the simultaneous determination of ascorbic acid and its derivatives in skin-whitening cosmetics

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 (C(18)) 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 microg/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.     

Determination of Tandospirone and its Impurities in Drug Formulations by LC-UV and LC-MS

This work describes the determination of tandospirone in bulk drug substance and formulated products by a reversed-phase liquid chromatographic method with UV detection. Chromatographic separation was performed on a C₁₈ column with a mobile phase of a binary mixture of methanol and water (70:30, v/v) delivered at a flow rate of 0.5 mL min^–1 and detection was performed at 243 nm. The proposed LC method is selective, precise and accurate for the determination of tandospirone in the presence of its manufacturing impurities with a limit of quantitation of 0.54 g mL^–1. A preliminary study for the identification of the major manufacturing impurities was made by liquid chromatography-mass spectrometry with electrospray ionization source operated in a positive ion mode.     

超高效液相色谱-四极杆-飞行时间质谱法测定防脱发化妆品中19种非法添加化学成分

建立了超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF-MS)法,结合高分辨质谱数据库,用于快速筛查及定量分析防脱发化妆品中19种非法添加化学成分.实验比较了提取溶剂的影响,优化了色谱条件和质谱条件.采用ACQUITY UPLC BEH C18色谱柱(100 mm×2.1 mm,1.7μm)进行色谱分离,以乙...     

高效液相色谱法测定化妆品中的泛酸及D-泛醇

建立了对不同基质化妆品(膏霜、乳液、水剂化妆品、油剂化妆品、蜡基化妆品、指甲油等)中泛酸(维生素B5)及D-泛醇(维生素原B5)的富集方法及同时测定的高效液相色谱(HPLC)法。利用水和与水不互溶的有机溶剂组成的双液相体系,首先将泛酸及D-泛醇与化妆品中油溶性成分及表面活性剂等基质成分初步分离,然后用亚铁氰化钾-乙酸锌共沉淀剂去除提取液中的水溶性成分,继而在酸性条件下将泛酸和D-泛醇富集于C18固相萃取填料上,脱除其他水溶性干扰物后,用40%甲醇水溶液洗脱,用HPLC分离,紫外检测器检测,外标法定量。该方法在泛酸和D-泛醇的含量为0.1～10 μg/g范围内有很好的线性,线性相关系数分别为0.9989和0.9996。不同化妆品基质中目标成分的方法回收率均在90%以上。对泛酸及D-泛醇的检出限均为30 μg/g,定量限均为100 μg/g。实验表明该方法可用于化妆品中泛酸及D-泛醇的同时测定,结果准确可靠。     

Determination of Dexamethasone in Cosmetics by MEKC

A rapid and reliable method based on micellar electrokinetic capillary chromatography has been developed for the determination of dexamethasone in cosmetics. Effects of buffer composition, concentration and pH, the detection wavelength, separation voltage, and injection time were systematically investigated. The optimum conditions were: 30 mM borax buffer containing 20 mM sodium dodecyl sulfate at pH 9.0, detection at 254 nm, injection time 10 s at a height of 10 cm, and a separation voltage of 15 kV. Under these conditions, the analysis of dexamethasone in cosmetics was carried out within 6 min. The method was validated for stability, precision, linearity and accuracy. Excellent linearity was obtained in the range of 50–1,000 μg mL⁻¹, and acceptable precision, in intra-day and inter-day analysis, was also obtained with relative standard deviation in the range of 0.19–0.86 and 2.50–4.90% for migration time and peak area ratio, respectively. The method was used to analyse eight cosmetic samples purchased locally.     

A reliable and environmentally-friendly liquid-chromatographic method for multi-class determination of fat-soluble UV filters in cosmetic products

An environmentally-friendly analytical method for the simultaneous determination of 15 fat-soluble ultraviolet (UV) filters currently authorized by the European Union regulation on cosmetic products has been developed. The determination was performed by liquid chromatography with UV spectrophotometric detection. Different parameters, such as type of column, oven temperature, mobile phase composition and flow rate were studied. The best chromatographic separation was obtained under the following conditions: C18 column set at 60 °C and gradient ethanol:water (containing 1% formic acid and 20 mM of 2-hydroxypropyl-β-cyclodextrin) as mobile phase pumped at 1 mL min⁻¹. 2-Hydroxypropyl-β-cyclodextrin was added as mobile phase modifier to achieve the complete resolution of some of the chromatographic peaks. The 15 target compounds were separated in less than 30 min. The method was satisfactorily validated by analyzing three laboratory-made cosmetic samples besides of eleven commercially available cosmetic products containing different combination of the target UV filters. Good accordance of the found levels compared with those of the laboratory-made samples and those of the commercial samples (when available) was achieved. Moreover, excellent recoveries (97–104%) and good intra-day and inter-day precision values at different concentration levels, besides limits of detection values below the μg mL⁻¹ level, were obtained. These good analytical features, as well as their environmentally-friendly characteristics, make the presented method suitable not only for routine analysis in cosmetics industries, but also as candidate reference method for sunscreen analysis.     

Multiresidue analysis of 59 nonallowed substances and other contaminants in cosmetics

A method was developed for the determination of 59 glucocorticoids, sex hormones, nonsteroidal anti‐inflammatory drugs, antibiotics, and other contaminants in cosmetics simultaneously by ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Acetonitrile was used to extract the sample, and the mixed sorbents were dispersed for purification. With the optimal conditions, the optimized pretreatment processes led to no significant interference on analysis from an extremely complicated sample matrix, and the linear ranges of 59 analytes were 0–480.0 μg/kg with the correlation coefficients above 0.99 and the limits of quantification (S/N≥10) were 5–40 μg/kg. Statistical evaluation revealed that the average recoveries were in the range of 61.2–131.2%, and relative standard deviations were in the range of 2.0–22.8%, meanwhile the interday precision ranged from 3.8 to 21.8%. This method is simple, fast, and credible, and it can be applied to simultaneous screening and determination of various classes of substances under investigations illegally presented in cosmetic products, covering a wide diversity of polarities, and pK_a values.     

Simultaneous determination of tartrazine and sunset yellow in cosmetic products by first-derivative spectrophotometry

A spectrophotometric method for the simultaneous determination of Tartrazine (TT) and Sunset Yellow (SY) in cosmetic products has been developed. An extraction process was carried out using methylene chloride and the colouring matters were measured in the aqueous phase formed, the other components of the sample remaining in the organic phase. The applicable concentration ranges were 0.5–10 ug/ml TT and 0.5–12 g/ml SY. The detection limits were 26 and 11 ng/ml and the relative standard deviations were 1.0 and 0.9% for TT and SY, respectively. The method was applied to the determination of both compounds in cosmetics.     

Analysis of multi-class preservatives in leave-on and rinse-off cosmetics by matrix solid-phase dispersion

Matrix solid-phase extraction has been successfully applied for the determination of multi-class preservatives in a wide variety of cosmetic samples including rinse-off and leave-on products. After extraction, derivatization with acetic anhydride, and gas chromatography–mass spectrometry analysis were performed. Optimization studies were done on real non-spiked and spiked leave-on and rinse-off cosmetic samples. The selection of the most suitable extraction conditions was made using statistical tools such as ANOVA, as well as factorial experimental designs. The final optimized conditions were common for both groups of cosmetics and included the dispersion of the sample with Florisil (1:4), and the elution of the MSPD column with 5 mL of hexane/acetone (1:1). After derivatization, the extract was analyzed without any further clean-up or concentration step. Accuracy, precision, linearity and detection limits were evaluated to assess the performance of the proposed method. The recovery studies on leave-on and rinse-off cosmetics gave satisfactory values (>78% for all analytes in all the samples) with an average relative standard deviation value of 4.2%. The quantification limits were well below those set by the international cosmetic regulations, making this multi-component analytical method suitable for routine control. The analysis of a broad range of cosmetics including body milk, moisturizing creams, anti-stretch marks creams, hand creams, deodorant, shampoos, liquid soaps, makeup, sun milk, hand soaps, among others, demonstrated the high use of most of the target preservatives, especially butylated hydroxytoluene, methylparaben, propylparaben, and butylparaben.     

Neutral desorption extractive electrospray ionization mass spectrometry for fast screening sunscreen agents in cream cosmetic products

High throughput analysis of sunscreen agents present in cream cosmetic has been demonstrated, typically 2 samples per minute, using neutral desorption extractive electrospray ionization mass spectrometry (ND-EESI-MS) without sample pretreatment. For the targeted compounds such as 4-Aminobenzoic acid and oxybenzone, ND-EESI-MS method provided linear signal responses in the range of 1-100 ppb. Limits of detection (LOD) of the method were estimated at sub-ppb levels for the analytes tested. Reasonable relative standard deviation (RSD = 8.4-16.0%) was obtained as a result of 10 independent measurements for commercial cosmetics samples spiked with each individual sunscreen agents at 1-10 ppb. Acceptable recoveries were achieved in the range of 87-116% for direct analysis of commercial cream cosmetic samples. The experimental data demonstrate that ND-EESI-MS is a useful tool for high throughput screening of sunscreen agents in highly viscous cream cosmetic products, with the capability to obtain quantitative information of the analytes.