I NDOOR A IR To evaluate the population exposure to pesticides from indoor air, some monitoring

10.2.4 I NDOOR A IR To evaluate the population exposure to pesticides from indoor air, some monitoring

studies are needed. These studies used mainly the same techniques that were used for outdoor air but adapted to confined atmosphere.

10.2.4.1 Sampling of Pesticides for Indoor Air Studies Stout and Mason 30 for their study on the distribution of chlorpyrifos following a

crack and crevice type application in the framework of the US EPA Indoor Air Quality Research House program used commercially available sampling tubes. These tubes consist of polyurethane foam open faced tube with no particle cutoff inlet (76 3 20 mm PUF plug in glass filter housing) and of OSHA versatile sampler or OVS tubes (SKC Inc., Eighty-Four, PA). The OVS tube consisted of a 74 3 13 mm glass housing containing a quartz filter and two 140 and 270 mg beds of XAD-2 sandwiched between PUF partitions.

The two types of tubes were suspended at 100 cm above the floor in the living room and sampling was done for 24 h at a flow rate of 3.8 and 1.0 L min 1 for PUF

and OVS, respectively, by using an SKC Universal XR sample pump. The sample inlets were directed towards the floor. Samples were collected prior to the application and at 1, 3, 7, 14, and 21 days postapplication. Following sample collection, the PUF and OVS tubes were capped with aluminium foil and individu- ally sealed in plastic bags. The tubes were put in ice chests at reduced temperatures for transport.

Bouvier et al. 31 for their comparison of the pesticide exposure of nonoccupa- tionally exposed subjects and some occupational exposure used a MiniPartisol air sampler 2100 (Rupprecht and Patashnik, East Greenbush, NY, USA) and a glass cartridge containing a polyurethane foam (PUF), (SKC, Blandford Forum, UK) for the collection of aerosols and a QM-A 1851 quartz fiber filter (Whatman, Maidstone, UK) for the collection of particulate matters. The MiniPartisol was placed on a table or working furniture at a height of approximately 1.60 m, in the main room of the workplace or in the living-room of the residences. Flow rate of the pumps was checked before and after each sampling with a mini-Buck Calibrator debitmeter (A.P. Buck, Orlando, FL, USA). The sampling lasted for 24 h without interruption at

1 a flow rate of 5 L min 3 ; the mean volume sampled was 7.1 m =24 h. Sampling was performed during a working day and this sampling method was based upon the

ASTM D 4861 –00 standard. Barro et al. 32 for the analysis of pyrethroids as well as other components of frequently used domestic insecticide preparations in indoor air used a vacuum pump working at 100 L min 1 (Telstar model S-8, Tarrasa, Spain). A known volume of air

278 Analysis of Pesticides in Food and Environmental Samples was pumped through a glass tube containing 25 mg of an adsorbent; Tenax TA of

mesh size 60 –80 (Supelco) and Florisil (activated overnight at 1058C) of 60–100 mesh size (Aldrich, Steinheim, Germany).

Teflon (PTFE) tubing was used for all connections. This method of sampling was previously used for polychlorobiphenyls. 32 Yoshida et al. 66 used quartz fiber filter disk (type 2500 QAT-UP, 47 mm diameter, ~0.64 mm thickness, Tokyo Dylec, Tokyo, Japan) and an Empore disk (type C18FF, 47 mm diameter, ~0.50 mm thickness, 3 M, MN, USA) connected to a small suction pump for 24 h at a flow rate of 5.0 L min 1 resulting in a total volume

of air passed through the adsorbents of 7.2 m 3 .

Prior to the sampling of airborne pesticides and other semivolatile organic compounds (SVOCs), the Empore disks were subjected to ultrasonic cleaning five times for 10 min each by 10 mL of acetone per disk, and the quartz fiber filter disks were heated at 4008C for 4 h.

The sampler was fixed using a tripod in the center of the target room at a height of 1.2 –1.5 m from the floor. SPME was also used for the analysis of pesticides in confined atmosphere, in 67 particular on greenhouses. Dichlorvos, an organophosphate pesticide, was first studied followed by an extension to 10 pesticides (bioallethrin, chlorpyriphos-methyl, folpet, malathion, procymidone, quintozene, chlorothalonil, fonofos, penconazole, and tri-

methacarb). 68 Sampling was performed by using polydimethylsiloxane –solid-phase microextraction (PDMS –SPME) fibers immersed in a 250 mL sampling flask through which air samples were dynamically pumped from the analyzed atmosphere (Figure 10.5). After a 40 min sampling duration, samples were analyzed by GC=MS.

Calibration was performed from a vapor-saturated air sample (Figure 10.6). The linearity of the observed signal versus pesticide concentration in the vapor phase was proved from spiked liquid samples whose headspace concentrations were measured by the proposed method (Figure 10.7).

The same all experiments, as those used for extraction of pesticides by SPME from water samples, were performed.

10.2.4.2 Extraction of Pesticides for Indoor Air Studies Classical methods using Soxhlet or an ultrasonic bath were used. Bouvier et al. 31

used Soxhlet extraction with 150 mL of dichloromethane Pestanal for 16 h for the

P SPME fiber

Septum

Air sample Pump

Stainless steel pipe Glass flask

FIGURE 10.5 Assembly used in greenhouse for SPME samplings. (From Ferrari, F. et al., Anal. Bioanal. Chem. , 379, 476, 2004.)

Sampling and Analysis of Pesticides in the Atmosphere 279

Pump

Stainless steel pipes

Septum

SPME fiber

Air saturated by pesticides vapor

Glass flask

2.5 L Flask

Pure pesticides FIGURE 10.6 Laboratory assembly used for calibration of SPME samplings of pesticides

vapors. (From Ferrari, F. et al., Anal. Bioanal. Chem., 379, 476, 2004.) extraction of pesticides from PUF plugs and quartz fiber filters. Barro et al. 32 for their

study on pyrethrenoids pesticides in indoor atmosphere used an ultrasonic bath for a few minutes. They put traps on a 22 mL glass vial and analytes were extracted into an appropriate volume of organic solvent (n-hexane or ethyl acetate).

SPME magnifold SPME fiber

Pesticides in air Glass vial

Pesticides in solution Stirring bar

Thermostatic bath

Heater-stirrer FIGURE 10.7 Assembly used for studying the linearity of HS–SPME samplings. (From

Ferrari, F. et al., Anal. Bioanal. Chem., 379, 476, 2004.)

280 Analysis of Pesticides in Food and Environmental Samples Yoshida et al. 66 used also 15 min ultrasonic bath for the extraction of pesticides

from glass fiber filters and Empore disks followed by shaking for 10 min. For this, they add 8.0 mL of acetone to a 10 mL centrifuge tube containing the two absorbents.

As mentioned in the paragraph of sampling of pesticides for indoor studies, the extraction of pesticides after sampling is made by direct exposure of the fiber in the split –splitless injector of the gas chromatograph.