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Environmental Science and Technology | Progress Report 233

met showing the way for total conformity and other unwanted species of contaminated
assessment. liquid effluents. This is especially interest-
ing when low-cost effective remediation
Analytical chemistry for is required. A Ca / P molar ratio of 1.667 is
environmental diagnosis consistent with the theoretical Ca / P ratio

for calcium hydroxyapatite with a composi-
The Laboratories of Chemistry and Envi- tional formula of Ca10(PO4)6(OH)2, whose
ronmental Diagnosis Center – CQMA have properties are well discussed in the literature.
established methodologies for evaluation of The aim of this work was implementing and
physical-chemical, chemical and toxicolog- validating a methodology for simultaneous
ical parameters to support several research determination of major and minor constit-
projects in development for environmental uents in the hydroxyapatite (HA) as well as
diagnosis. All methodologies adopted are providing the Ca / P molar ratio. To accomplish
established in the standard methods (ASTM, these achievements, wavelength dispersive
EPA) or specified by the clients. The classic x-ray fluorescence spectroscopy (WDXRF)
methods and instrumental techniques anal- was applied. This is a non-destructive tech-
ysis such as atomic absorption spectrometry nique that requires no chemical treatment,
(AAS), inductively coupled plasma emission enabling fast chemical analysis in a wide
spectrometry (ICP-OES), ion chromatography variety of samples, with no hazardous waste
(IC), gas chromatography (GC), gas chroma- being generated as a result of the process of
tography mass spectrometry (GCMS), high determination. A standard reference mate-
performance liquid chromatography (HPLC;), rial from NIST (SRM 1400 –Bone Ash) was
X-ray fluorescence (WD-XRFS) have been used. used to validate the methodology for the
The Center has been participating in several determination of magnesium, phosphorus,
international and national interlaboratory potassium, calcium, iron, zinc, strontium and
programs sponsored by: IAEA (International the Ca / P ratio in HA samples by WDXRF. The
Atomic Energy Agency), INTI (Instituto Na- Z-score test was applied as a statistical tool
cional de Tecnologia Industrial, Argentina), and showed that the calculated values were
SENAC (Brasil), ABACC (The Brazilian-Argen- of less than 1.8 for all the measured analytes.
tine Agency for Accounting and Control of
Nuclear Materials), SABESP. (Basic Sanitation X-Ray Fluorescence Techniques
Company of the State of São Paulo, Brasil) and applied to environmental, geological
Rede Metrológica Rio Grande do Sul (Brasil). and biological studies Chemical
characterization of nuclear and non-
Determination of a Ca/P Molar nuclear materials R&D activities
Ratio in Hydroxyapatite (HA) by
X-Ray Fluorescence Technique The X-Ray Fluorescence Laboratory (LFX) has

worked in environmental, biological and
Hydroxyapatite (HA) is a mineral composed of nuclear areas, establishing new analytical
calcium phosphate employed for endodontics, methodologies using the X-ray fluorescence
restorative dentistry and other applications spectrometry (WDXRF, EDXRF). Different
in orthopedics and prosthesis. Additionally, matrices, such as soils, sediments, lubricat-
this biomaterial is an inexpensive but efficient ing oils, treated wood, metal environmental
adsorbent for the removal of heavy metals pollution monitoring trees, organic fluids