Sampling and Laboratory Analysis for Solvent Stabilizers - Environmental Investigation and Remediation - page 221

provider, where a whole-volume standard with a value similar to concentrations found at a
i eld site is prepared and i lled in the container and then express-shipped back to the labora-
tory client. The client then labels the sample with a i ctitious name similar to names of other
samples in the set and ships it in a cooler with other i eld samples from a sampling event.
Laboratory results are then compared with the value of the whole-volume standard given
by the standards provider. Laboratory performance can then be gauged to coni rm that the
laboratory's in-house quality control tests are accurate. Because there is analytical error asso-
ciated with both the whole-volume standard and the subject laboratory's analysis, the com-
bined error range can be larger than the errors of the individual analyses. Nevertheless, the
laboratory client can use double-blind standards to independently verify the reasonableness
of reported results.
Standards for 1,4-dioxane and 1,4-dioxane-d 8 can be purchased from laboratory stan-
dards providers. If desired, the whole-volume standard can be prepared by using the same
matrix as other samples in the set—for example, groundwater from a monitoring well that
has consistently tested nondetect for 1,4-dioxane—and then analyzing a second sample from
a whole-volume split of that groundwater to coni rm absence of 1,4-dioxane. Matrix-matched
double-blind standards prepared in this manner are less obvious to laboratory analysts, who
might otherwise recognize a double-blind standard by its low electrical conductivity and use
extra care when conducting the analysis.
4.5.7 E NVIRONMENTAL P ROTECTION A GENCY M ETHOD 522—S OLID -P HASE E XTRACTION AND
G AS C HROMATOGRAPHY -M ASS S PECTROSCOPY WITH S ELECTIVE I ON M ONITORING
USEPA's National Exposure Research Laboratory is developing a new method for measuring 1,4-
dioxane and other water-soluble solvent-stabilizer compounds in drinking water. The method applies
SPE, using coconut charcoal as the solid sorbent and dichloromethane as the eluent, to extract and
concentrate hydrophilic volatile organic chemicals from water matrices. Extracts are analyzed by
GC-MS with large-volume injection. Preliminary trials achieved recovery of 1,4-dioxane from
both reagent and tap water at 89.5% and 95.3%, respectively, with RSDs of less than 6.3% (Munch,
2006). Preliminary data for four other solvent stabilizers—1,2-butylene oxide, 1,3-dioxolane,
t -butanol, and epichlorohydrin—demonstrate 92.5-114% recovery with RSDs of less than 5.1%
(Munch, 2006). USEPA is developing this method as EPA Method 522, which has been drafted and
is undergoing evaluation (personal communication with Andrew Eaton, Vice President, MWH
Laboratories, Monrovia, California, June 2008).
4.6 LABORATORY SAFETY FOR 1,4-DIOXANE HANDLING AND
INSTRUMENT CLEANING
1,4-Dioxane can react with oxygen to form explosive peroxides. Discovery of old bottles of full-
strength ethers can lead to expensive removal by demolition experts, or worse, accidental detonation.
The peroxide crystals often form around the threads of the bottle top and explode when compressed
if an unsuspecting laboratory chemist attempts to open the bottle. This problem is more likely to
occur at facilities using pure 1,4-dioxane such as histology laboratories, liquid scintillation counters,
and research chemistry laboratories. Several news stories have proi led incidents in which old cans or
bottles of dioxane have been discovered, including a hospital in Fort Lauderdale, Florida, a laser
facility in Santa Clara, California, and a college laboratory in Salisbury, North Carolina. In each
case, these discoveries caused facility shutdown and a bomb squad response to remove the container
of 1,4-dioxane to a remote location for detonation. Once peroxides form, controlled detonation is the
safest method to remove the hazard. The explosive power of a gallon of peroxidized 1,4-dioxane is