C. T. Yap

X-ray Total Reflection Fluorescence Analysis of Iron, Copper, Zinc, and Bromine in Human Serum

The method of total reflection fluorescence analysis was used to obtain concentrations of iron, copper, zinc, and bromine in human sera. It was first applied to the commercial control-serum preparation known as Seronorm, and the results obtained were in good agreement with quoted values. The method was then used to determine the concentrations of iron, copper, zinc, and bromine in a random sampling of 62 individuals in an essentially Chinese population. The results are discussed. We feel that this is a suitable method for trace-element analysis of blood in an average laboratory. It is rapid, simple, and economical, besides being multielemental and nondestructive and requiring very small quantities—which seems to be a must in pediatrics.

A Rapid EDXRF Method of Simultaneous Quantitative Elemental Analysis Using an Annular Cd-109 Source

Recent EDXRF studies of Chinese ceramics of the Ming (1368–1644) and Qing (1644–1911) dynasties, the Republic period (1912–1939), and the modern period (after World War II) have given encouraging results for the identification of modern fake reproductions and the attribution and dating of Chinese porcelains. However, quantitative elemental determination requires tedious calibration procedures. In general, a separate calibration curve is required for each element to be determined, and, when one is using Cd-109 sources, quantitative elemental determination (say from Mn to Nb) would be rather time-consuming.

Calibration of the Radioisotope-Excited X-Ray Spectrometer with Thick Standards

Calibration of the energy-dispersive x-ray fluorescence spectrometer with Cd-109 annular excitation source is discussed. Experiments were performed to calibrate such a spectrometer using both thick standards and one type of commercially available, thin, single-element standard. It was found that the use of thick standards in such calibrations is reliable and accurate, in addition to being inexpensive and readily available.

Raw Materials for Making Jingdezhen Porcelain from the Five Dynasties to the Qing Dynasty

This is a study of 66 pieces of Jingdezhen porcelain bodies and their relation to 13 raw materials, three of which are kaolin and the rest porcelain stones from Jingdezhen. For Jingdezhen porcelains, the results show that the alumina content increases and silica content decreases as a function of time, except during the Yuan and Ming Dynasties, when this trend was reversed. For raw materials, although kaolin could never be used alone for porcelain production, four of the porcelain stones could be used alone for this purpose during the Five Dynasties and part of the Song Dynasty. However, all porcelains made thereafter have varying amounts of kaolin added to the porcelain stone. Except for a reversal during the Yuan and Ming Dynasties, we found that the amount of kaolin added was a function of time, reaching as high as about 60% during the Qing Dynasty.

TXRF spectrometric analysis of major elements in mineral sands

The major elements of mineral sands such as rutile and ilmenite vary widely in their concentrations. A method is developed with the use of thin-film samples and the total reflection x-ray fluorescence technique to obtain quantitative concentrations of such samples. The method was tested with the use of the GSJ (Geological Survey of Japan) rock reference JB-3, and agreement with quoted values was good. The advantages of the method are the simplicity of sample preparation, including easy removal of samples from the reflector; the low background contribution from the substrate; and the small quantity of the sample that is required.

Constancy in Elemental Composition of Identical and Symmetrical Ceramic Pairs

Recently much work has been done on Chinese porcelains with the use of the EDXRF technique; the results have been encouraging. In general, quantitative elemental determination requires tedious calibration procedures. In this study, we shall use a simplified, rapid EDXRF method to obtain quantitative values of trace elements of rubidium, strontium, yttrium, zirconium, and niobium. Briefly, the method makes use of the calibration curve on a plot of ln[intensity (cps)/concentration (%)] vs. ln[energy (keV)] for the elements Rb to Nb. Using such a calibration curve, we were able to obtain quantitative values of the concentration of the element by simply measuring its intensity under the same geometrical conditions.

A Method for Quantitative Multielemental Analysis of Specimens of Low-Z Matrix by Photon-Excited X-Ray Fluorescence

A method is described for obtaining the concentrations of trace elements in samples of low-Z matrix by measuring the intensities and transmittances of such samples of intermediate thickness in pellet form. This method has been applied to the determination of the minor and trace elements of Certified Reference Material IAEA/V-10 hay powder, and the results are in good agreement with quoted values.

Theoretical Studies in EDXRF on a New Linear Relation: In(Fluorescent Intensity Ratio of Analyte to Pure Analyte/Concentration of Analyte) versus In(Fluorescent Energy)

The inaccuracies and validity of the approximate linear relation between In(fluorescent intensity/concentration) and In(fluorescent energy) are presented and discussed. We then present the derivation of a new linear relation between In(fluorescent intensity ratio of analyte to pure analyte/concentration of analyte) and In(fluorescent energy) which is valid for all elements that can be excited by radiation sources, whether by tube x-ray or by radioisotope sources.

Principal Component Analysis of Trace Elements from EDXRF Studies

With the use of the EDXRF technique, the concentrations of 14 trace elements (Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Y, Zr, Nb, and Mo) of Japanese pottery samples from three different regions were measured. Principal component analysis shows the possibility of discriminating between the various trace elements in terms of their being either useful or not useful variables by which Japanese pottery samples could be grouped according to their geographical origin.

Experimental Studies in EDXRF on a New Linear Relationship for Fluorescence

An experiment was carried out to verify a previously described linear relationship between ln(fluorescent intensity ratio of analyte to pure analyte/concentration of analyte) and ln(fluorescent energy) or, mathematically, ln(Ii/ciIi0 = a ln(Ei) + b. The best fit to our experimental data for elements from manganese to molybdenum for porcelain matrix is given by ln(Ii/ciIi0) = 2.401 ln(Ei) – 8.701 with a value of the gradient in agreement with the theoretical prediction.