F10 Measuring Some Environmentally Sensitive Elements Using Wavelength Dispersive X-ray Spectrometry

Anti-HIV-1 Activity of Poly(mandelic acid) Derivatives

“…The resulting electromagnetic radiation is characterized either by its wavelength (λ) or by its energy ( E ). , When the electron is ejected from the 1s orbital, the electromagnetic radiation is termed the X-ray k-series, and the wavelength of the emitted photons is given by 1/λ = K × [ Z − α], where K is a grouping of fundamental constants, Z is the atomic number of the element, and α is the electron density screening constant for the element. The wavelengths of the characteristic K-series X-rays emitted by each of the elements are well-known. , The measured intensity for the k α photons of the peak for element Z , I ( Z ), is related to the abundance, C z , of that element in a sample by: where Q is the instrumental calibration constant, M is the matrix effect of the entire sample, and P represents specimen effects. , The product Q × M × P may be eliminated by selection of a series of “standard mixtures”, which contain both the analyte Z and the other elements in the sample(s) to be analyzed. , Thus, C z * = I *( Z ) × [ C °( Z )/ I °( Z ), where C °( Z )/ I °( Z ) is the relationship between the abundance of analyte Z in reference samples of known composition and the measured analyte intensity from the WDXRS of each reference. Because each is composed predominantly of carbon and hydrogen and each contains a small amount of sulfur, PMDA and poly(sodium 4-styrenesulfonate) fit this relationship.…”

“…27,28 The product Q × M × P may be eliminated by selection of a series of "standard mixtures", which contain both the analyte Z and the other elements in the sample(s) to be analyzed. 29,30 Thus, C z * ) I*(Z) × [C°(Z)/I°(Z), where C°(Z)/ I°(Z) is the relationship between the abundance of analyte Z in reference samples of known composition and the measured analyte intensity from the WDXRS of each reference. Because each is composed predominantly of carbon and hydrogen and each contains a small amount of sulfur, PMDA and poly(sodium 4-styrenesulfonate) fit this relationship.…”