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Lamentablemente no disponemos de información para satisfacer su inquietud. Le
envío copia de esta respuesta al Dr. Federico Contreras quien siempre colabora
con nosotros en la parte analítica. Si el tiene información seguramente se la
proporcionará.
POSTERIORMENTE
Le adjunto la respuesta del Dr Federico Contreras con la información
solicitada por Udes.
"La N Acetil 2 Hidroxietil Cisteína se menciona efectivamente en la última
edición del libro de Albiano como una sustancia en estudio para el monitoreo de
exposición al óxido de etileno, aunque no se mencionan valores (sí existen
máximos de óxido de etileno de 0.5 mg/m3 en aire espirado y 0.8 microgramos/dl
en sangre durante la exposición). Les adjunto un abstract de JAT sobre el tema
donde se menciona la metodología y trataré de averiguar si alguien lo está
haciendo por acá, lo que por el instrumental parecería bastante improbable.
".
Publicado en el Journal of Analytical Toxicology, Volume 22, Number 2,
March/April 1998, pp. 96-104.
A Rapid, Sensitive Method for the Quantitation
of N-Acetyl-S-(2-Hydroxyethyl)-L-Cysteine in Human Urine Using Isotope-Dilution
HPLC-MS-MS
D.B. Barr and D.L. Ashley
Because of increasing concern about
exposure to carcinogens and other toxicants, reliable methods for biological
monitoring of potentially exposed populations must be developed. For biological
monitoring to be useful, appropriate biomarkers of exposures to xenobiotics must
be identified, and sensitive, specific methods for quantifying the targeted
biomarker must be developed. We have developed a sensitive and selective method
for the analysis of N-acetyl-S-(2-hydroxyethyl)-L-cysteine (HEMA), a urinary
metabolite of at least three different known human carcinogens (vinyl chloride,
ethylene oxide, and ethylene dibromide). The method uses strong anion-exchange
solid-phase extraction and isotope-dilution high-performance liquid
chromatography-tandem mass spectrometry. Our method is simple and is not labor
intensive; the preparation time per sample is less than 10 min. Because urine
samples vary in both their concentration and ion strength, intersample
variability in HEMA recovery during the extraction is large. To overcome this
inherent limitation, we use the isotope-dilution technique, which allows a
complete correction for the extraction recovery for each sample. The limit of
detection of the method is 0.68 µg/L in a 1-mL urine sample with a coefficient
of variation of 22% (determined by replicate analyses at both 4 and 11 µg/L) and
an accuracy indistinguishable from 100%. Preliminary analyses of urine from a
population with no known overt exposure to the parent toxicants show a frequency
of detection of approximately 75%, which indicates that this method has the
sensitivity to detect urinary HEMA derived from environmental exposure. We are
currently using this method to establish a reference range of background
exposure to these toxicants in the U.S. population. |
