排序方式: 共有35条查询结果,搜索用时 15 毫秒
31.
建立了同时测定防晒类化妆品中帕地马酯A和帕地马酯O的高效液相色谱分析方法及质谱确证方法。化妆品样品以甲醇为提取溶剂进行超声提取,提取液离心处理,取上清液经微孔滤膜过滤后测定。采用XTerra MS C18柱(250×4.6mm,5μm)分离,外标法定量。结果表明防晒类化妆品中帕地马酯A和帕地马酯O的方法定量限均为0.5mg/kg,在低、中、高3个添加水平范围内平均回收率为89.1%~112.5%,相对标准偏差为2.0%~7.7%。对于疑似阳性样品,进一步采用液相色谱-串联质谱法进行确证分析。该方法准确、快速、灵敏度高,适用于防晒类化妆品的实际检验工作。 相似文献
32.
No previous publications about percutaneous absorption of polyethylene glycol 25 p-aminobenzoic acid (PEG-25 PABA) have been found in the literature and the expected levels to be found in human urine after sunscreens use are unknown. The method proposed here is suitable to determine PEG-25 PABA in the urine of sunscreens users in order to carry out studies on body accumulation/excretion. It is based on solid-phase extraction (SPE) with size-exclusion liquid chromatography determination. Solid-phase extraction allows the analyte to be retained and subsequently eluted for a clean-up, using a silica-based cartridge. The size-exclusion liquid chromatography of the eluted allows the rest of matrix interferences to be avoided. Fluorescence intensity was measured at λem = 350 nm (λexc = 300 nm). The sensitivity of the proposed method is in the order of 450 ± 5 mL ng−1 and the detection limit (3 Sy/x/b) in the measured solutions is in the order of 13 ng mL−1, that is 2.6 ng mL−1 in urine samples. The method enables PEG-25 PABA to be determined in both, spiked and unspiked human urine samples. Results obtained for spiked human urine samples (11-100 ng mL−1) demonstrated the accuracy of the method. The mean relative standard deviation of the results was in the order of 3-10%. Three volunteers applied a sunscreen lotion containing a 8% PEG-25 PABA sunscreen cream and their urinary excretion was controlled from the moment of application until the excreted amounts were no longer detectable. 相似文献
33.
用线性扫描极谱法系统研究了2,2′,4,4′-四羟基二苯甲酮(简称BP-2)在不同缓冲体系中的极谱行为.实验表明,在pH=2.25的B-R缓冲溶液中,BP-2的一阶导数峰电位为-1.12 V,其峰电流与浓度在5.0×10-6~9.0×10-5mol/L范围内的对数值有良好的线性关系,线性方程为ip′(nA/s)=11 457 2 133×lgc(mol/L),相关系数为0.9998.BP-2的微分循环伏安研究表明,该极谱波为不可逆还原波;初步讨论了电极反应机理. 相似文献
34.
Alessio Becheri Maximilian Dürr Pierandrea Lo Nostro Piero Baglioni 《Journal of nanoparticle research》2008,10(4):679-689
We report the synthesis and characterization of nanosized zinc oxide particles and their application on cotton and wool fabrics
for UV shielding. The nanoparticles were produced in different conditions of temperature (90 or 150 °C) and reacting medium
(water or 1,2-ethanediol). A high temperature was necessary to obtain small monodispersed particles. Fourier transformed infrared
spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray powder diffractometry (XRD) were used to characterize
the nanoparticles composition, their shape, size and crystallinity. The specific surface area of the dry powders was also
determined. ZnO nanoparticles were then applied to cotton and wool samples to impart sunscreen activity to the treated textiles.
The effectiveness of the treatment was assessed through UV–Vis spectrophotometry and the calculation of the ultraviolet protection
factor (UPF). Physical tests (tensile strength and elongation) were performed on the fabrics before and after the treatment
with ZnO nanoparticles. 相似文献
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