At the end of the collection, the hopcalite tubes were sealed at their ends and packed in a foam-lined metal case to ensure the integrity of the sample until laboratory analysis.
The adsorbent contained in the hopcalite tube was transferred to a 25 mL volumetric flask, adding 2.5 mL of HN[O.sub.3] and 2.5 mL of HCl, both analytical grade concentrated reagents (Merck), without any previous treatment.
The limit of detection (LOD) and limit of quantification (LOQ) were determined by multiplying by 3 and 10, respectively, the standard deviation (SD) of the mean of seven independent preparations of the blank of the hopcalite tube sample, where LOD = 0.06 and LOQ = 0.22 [micro]g x [L.sup.-1].
It's filter will transform cabon monoxide to carbon dioxide with the hopcalite that is in the filter," Allali says.
The masks use hopcalite, a manga-nese/copper oxide filter to convert carbon monoxide into carbon dioxide.
All samples were collected, with personal air samplers, for analysis of mercury concentrations by solid sorbent tube (hopcalite in single section, 200mg, SKCInc., PA, USA) (Gilian,Gilair-5RPAir Sampler).
Quantitatively transferred the hopcalite sorbent and the front glass wool plug from each sampler tube into a 100mL volumetric flask.
EPA has found that one AAS analyzer, the Lumex RA915, is comparable in sensitivity and accuracy with
Hopcalite tubes.
The passive dosimeters used
hopcalite as the solid sorbent, which was digested with nitric and hydrochloric acid.
Four months after the children took the [Hg.sup.0], airborne [Hg.sup.0] levels in the home measured with Hopcalite (SKC, Inc., Eighty Four, PA) tubes were very high--110 [micro]g/[m.sup.3] in the living room and 140 [micro]g/[m.sup.3] in the basement family room.
Air sampling with Hopcalite absorbent tubes and sampling pumps can be done for clearance sampling after a cleanup has been performed, but they require laboratory analysis.