EM - IUEM - Técnicas Laboratoriais Forenses
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- Influence of temperature on L-aspartic acid racemization : a forensic dentistry approachPublication . Naceva, Ana; Noronha, João Paulo; Pereira, Cristiana PalmelaForensic age estimation is a branch of forensic medicine that aims to estimate the chronological age of a person involved in criminal or legal proceedings. Different methods for age estimation have been developed over the years. Among them the method of aspartic acid racemization has imposed itself as one with very high accuracy rate. There are several limitations to this method and all of them are closely related to the influence of environmental conditions on aspartic acid racemization. Understanding the influence of environmental conditions on AAR is highy important as it leads to improvement of the method itself. Standards of L-Asp were placed in solutions with pH 3, 5 and 9 and exposed to temperatures in the range of 22 °C to 110 °C for 72 hours. The results were measured by a circular dichroism spectropolarimetry and revealed an increase of D-Asp with the increase of temperature in all samples. Quantitative and qualitative analysis of amino acids in human dentin was performed using extraction method previously described in literature. BSTFA was used as a derivatization agent. The profile of amino acids detected concurs with results found in literature, with a minor discrepancy that maybe due to difference in operating conditions. Moreover, preliminary studies on several derivatization techniques were explored for separation of aspartic acid enantiomers in human dentin. A “cold” derivatization technique using alkyl chlorformates coupled with SPME extraction provided successful derivatization of DL-Asp and DL-Nor. The compounds were latter eluted on an achiral column in GC-MS.