Correction

Anal. Chem. 1997, 69, 801

Coupled Subcritical Water Extraction withSolid-Phase Microextraction forDetermining Semivolatile Organics inEnvironmental Solids

Kimberly J. Hageman, Laurent Mazeas,Carol B. Grabanski, David J. Miller, andSteven B. Hawthorne*(Anal. Chem. 1996, 68, 3892-3898)

We wish to clarify the assembly of the extraction cell andemphasize a related safety issue. The cell was constructed witha stainless steel pipe fitted with threaded (npt) caps. One endwas capped, the sample was added, and then water was added toa volume of 3.5 mL including 2.5 mL for the pipe fitting and anadditional 1.0 mL for the end cap. The filled cell was then sealedwith a second cap, thus creating a 1-mL headspace (for a totalcell volume of 4.5 mL). This headspace is absolutely required sothat the maximum pressure does not exceed the steam/waterequilibrium pressure. Although it was not possible to fill thedescribed cell completely (and thus the pressure safety marginwas maintained by the steam/water equilibrium), this procedureshould NEVER be used with a cell design that does not includea suitable headspace volume because heating a completely filledcell could result in pressures exceeding several thousand bar.1

(0) Haar, L.; Gallagher, J. S.; Kell, G. S. National Bureau of Standards/National Research Council Steam Tables; Hemisphere Publishing Corp.:Bristol, PA, 1984.

AC9613951

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