High-performance liquid chromatography of methotrexate for environmental monitoring of surface contamination in hospital departments and assessment of occupational exposure
L. Floridia et al., High-performance liquid chromatography of methotrexate for environmental monitoring of surface contamination in hospital departments and assessment of occupational exposure, J CHROMAT B, 726(1-2), 1999, pp. 95-103
In the frame of applicative research in occupational hygiene of hospital wo
rkplaces, we investigate hospital indoor contamination as a consequence of
the use of antineoplastic drugs (ANDs), with the purpose of assessing expos
ure of medical and nursing personnel to potentially harmful doses of ANDs,
and ultimately of yielding advice on safe operating procedures for manipula
tion of ANDs in hospitals and in house-care of cancer patients. Among the l
arge number of currently employed ANDs, methotrexate (MTX) has been selecte
d as a tracer of surface contamination, on the basis of its wide use in the
rapy, its ease of measurement and of its chemical properties relevant to pe
rsistence and transport in the indoor environment, MTX is a polyelectrolyte
, with a high water, but lower organic solvent solubility, a negligible vap
our pressure and a high chemical robustness to environmental stress, thus a
llowing to measure surface-to-surface carryover (e.g. from spillage or glov
e fingerprint) and indoor contamination due to aerosol transport (e.g. from
syringe manipulation procedures). Monitoring of MTX in environmental sampl
es such as swab washings of surfaces and objects requires an analytical met
hod with characteristics of sensitivity, reproducibility, precision, analyt
ical speed, ease of automation and robustness. We have therefore developed
an analytical procedure which employs simple short-column RP-HPLC with UV d
etection, automated sample injection and a close analogue internal standard
for improved precision and solid-phase extraction (SPE) for sample concent
ration. Our method has proven suitable for detecting traces of MTX on a wid
e variety of surfaces and objects, with a limit of quantification in the ra
nge of 50 mu g/dm(3) for direct injection of unconcentrated washings, corre
sponding to the possible detection of surface contamination as low as 1 mu
g/m(3) and a limit of detection in the range of 10 ng/m(2) for samples as l
arge as 100 dm(3) concentrated by SPE. We present preliminary results from
a recent hospital case-study, assessing the contamination level of furnitur
e and equipment in drug preparation areas. Spillage fractions as high as 5%
of the employed mass (70-260 mg/day) are measured on the polythene-backed
paper disposable hood cover sheet; traces of MTX in the microgram range can
also be measured on floor surfaces, furniture and handles, even at a dista
nce from the preparation hoods. (C) 1999 Published by Elsevier Science BN.
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