Akihiko Kawauchi

Measurement of Titanium Dioxide in Cosmetic Products with X-Ray Fluorescence Spectrometry

Abstract This paper reports the development of a simple method for measuring titanium dioxide in cosmetic products using X-ray fluorescence. A sample is prepared by stirring in a dispersion medium and then filtering with a 0.1 μm pore size membrane filter. The titanium dioxide particles trapped on the dried membrane filter are then measured with a wave-length dispersive X-ray fluorescence spectrometer. This sample preparation procedure was investigated using scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDX) mapping, inductively coupled plasma atomic emission spectrometry (ICP-AES) and turbidimetry. Interferences can be separated from the titanium dioxide layer on the membrane filter with this preparation procedure. The relative standard deviation for the analysis is less than 0.4%, the recovery is more than 99.0%, and the calibration curve gives a correlation coefficient of R = 1.000. The detection limit for titanium dioxide using this procedure is 0.02% by weight in product. ...

Quick identification of polymeric dye transfer inhibitors in laundry detergents by pyrolysis-gas chromatography/mass spectrometry

Abstract This report summarizes method development for the simultaneous identification of dye transfer inhibitors (DTIs) using pyrolysis-gas chromatography with mass detection (Py-GC/MS). Ground detergent products are directly pyrolyzed and pyrolysis fragments introduced into a GC column. Key fragments separated via GC are detected by selected ion monitoring (SIM) to achieve the high sensitivity and selectivity necessary to measure markers of DTIs in the presence of high levels of surfactant by products. Trace levels of DTIs, poly- N -vinylpyrrolidone (PVP), copolymer of N -vinylpyrrolidone and N -vinylimidazole (PVPVI), and poly-4-vinylpyridine- N -oxide (PVNO) in laundry detergent products were quickly identified. Detection limits were 0.05% for PVP and 0.1% for PVPVI and PVNO.

Quick identification of polycarboxylates in laundry detergents by in situ pyrolysis-methylation gas chromatography/mass spectrometry

Abstract This report summarizes method development for the identification of polycarboxylates using in situ pyrolysis-methylation gas chromatography (GC) with mass detection. Ground detergent products are dissolved in water together with a methylation reagent, tetramethylammonium hydroxide. The solution is centrifuged and an aliquot of supernatant is pyrolyzed after water is evaporated. Key fragments separated via GC are detected with a mass selective detector. Polycarboxylates in laundry detergent products are quickly identified. Detection limit is for polyacrylate and polymaleate is 1.0% by weight in product.

Measurement of zeolite, silicate, and phosphate in laundry detergent products by inductively coupled plasma atomic emission spectrometry

This paper reports the development of a method for simultaneously measuring zeolite, silicate, and phosphate in laundry detergent products by inductively coupled plasma atomic emission spectrometry. A sample is decomposed under alkaline oxidative conditions to decompose zeolite, silicate, phosphate, and organic substances. Then hydrochloric acid is added to the decomposed solution to dissolve aluminum hydroxide precipitate before analysis. This sample preparation procedure was investigated by using a total organic carbon analyzer and was confirmed to be applicable to simultaneous measurements of zeolite, silicate, and phosphate. Relative standard deviation for the analysis is less than 2.1%, recovery is more than 99.0%, and the calibration curve gives a correlation coefficient ofR=1.000. The detection limit of this method for aluminum and silicon is 0.1%, and for phosphorus, 0.2% by weight in the product. This method is applicable to various laundry detergent products that contain zeolite, silicate, or phosphate and is five times faster than the three wet chemical methods.

X-ray Fluorescence Analysis: Investigation of Microdroplet Sample Preparation

Abstract This paper reports the investigation of microdroplet sample preparation for phosphate, strontium and rubidium using X-ray fluorescence. Sample filter papers were prepared by drying under several different conditions and the front and the back sides of the filter papers were measured using X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron-probe microanalysis (EPMA). It was reported by Murata and Murokado that the elemental distribution difference between the front and the back sides after drying the filter paper led to erratic data.1 It has been found that the intensity difference between the front and the back sides was due to the condensation of the material of interest on the surface of the filter papers and the amount of the condensed material on the filter paper was related to the temperature at which the filter paper was dried. Optimum temperature at which a filter paper is dried and an appropriate internal standard are essential to reproduci...