Bio-VOC Brochure0 pages

Mi BBIOV
Background
Volatile organic chemicals (VOCs) are used extensively in
industry and are present in the ambient environment in low
concentrations. Primary routes of exposure for humans
include skin absorption, ingestion and inhalation. Biological
monitoring, ie measuring the body burden of VOCs, is a way
of assessing total exposure by all routes. It also provides vital
information on the potentially harmful build-up of chemicals in
the body – particularly in fatty tissues - after prolonged lowlevel
exposure.
Conventional biological monitoring methods measure the
target compounds or their metabolites directly in blood or
urine. Blood concentrations are judged to be the best guide to
overall levels of chemicals in the body. However, methods to
sample blood from individuals who may be at risk are
invasive, unpopular with those being tested and require
specially trained staff. This has made it expensive and
practically difficult in the past to undertake large scale surveys
of biological exposure, either at the workplace or of the
general public, on a routine basis. As a result, occupational
and environmental scientists have had to content themselves
with standard tests of chemical concentrations in the
atmosphere and ignore or calculate potential additional
exposure via skin absorption and ingestion.
The Bio-VOC Sampler
The development of the Bio-VOC sampler for exhaled air has
dramatically changed this situation. Based on pioneering
work carried out at the UK Health and Safety Laboratory, the
Bio-VOC sampler (figures 1 & 2) from Markes International
Limited provides, for the first time, a non-invasive and lowcost
solution to large scale biological monitoring.
The breakthrough came as scientists at the UK Health and
Safety Laboratory (HSL) in Sheffield decided to harness the
close relationship between chemical concentrations in the
blood and the air deep down in the lungs – so-called ‘endtidal’
air1. There is a rapid, almost instantaneous, exchange
betweeen volatile organics in the blood and air across the thin
membranes surrounding the alveolar portion of the lungs. In
fact the concentration of organics in alveolar air responds so
rapidly to changes in blood concentration that the organics in
the end-tidal air can be considered to be in constant
equilibrium with those in the blood. As the human body
provides a very well controlled environment for this
equilibrium, chemical concentrations in the blood can be
accurately derived from those in the breath. Measurement of
the VOC concentration in end-tidal air – the last portion of the
exhaled breath – was therefore proposed as an alternative,
non-invasive, method for biological monitoring.
The Bio-VOC Sampler was designed by staff at the HSL, and
their collaborators TCM Associates. It collects a
representative sample of end-tidal air, without contamination
or dilution with breath from the bronchial tubes or mouth, and
subsequently transfers it to a concentrating (sorbent) trap or
direct read-out instrument. The Sampler is now commercially
available from Markes International Ltd.
Application
Constructed of safe, non-emitting plastic the Bio-VOC
Sampler may be operated with minimal training and without
medically qualified staff in attendance. In field trials, the
sampler has been well received both by industrial health and
hygiene professionals and shopfloor workers.
An adult, exhaling deeply, typically breathes out over 4L of air.
Only the last 100 ml of this, all from the alveolar portion of the
lungs, is retained by the Bio-VOC Sampler. Once the breath
The Bio-VOCTM Sampler
Award-Winning Device for Non-Invasive Measurement of the Body Burden
of Volatile Chemical Pollutants
Figure 1. The Bio-VOC Sampler being used
Figure 2. The Bio-VOC sampler with capped sorbent tube,
CapLok tool and cardboard mouthpiece
Markes International Ltd
Unit D3, Llantrisant Business Park, Pontyclun, RCT, CF72 8YW, UK
Tel: +44 1443 230935 Fax: +44 1443 231531 email: enquiries@markes.com http://www.markes.com