1998-03-23_REVISION - M1977348 - Laserfiche WebLink

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.' 3.0 INTERFERENCES I ' 3.1 Potential interferences that may be encountered during ~malysis are ~: , discussed in the individual analytical methods. ~ 4.0 APPARATUS AND MATERIALS ;~ 4.1 Agitation apparatus: The agitation apparatus must be capable of rotating the extraction vessel in an end-over-end fashion (see Figure 1) at 30 ± 2 rpm. Suitable devices known to EPA are identified in Table 2. ' =. 4.2 Extraction Vessels ', 4.2.1 Zero Headspace Extraction Vessel (ZHE). This device is for use only when the sample is being tested for the mobility of volatile analytes (i_e., those listed in Table 1). The ZHE (depicted in Figure 2) allows for liquid/solid separation within the device and effectively precludes headspace. This type of vessel allows for initial liquid/solid separation, extraction, and final extract filtration without opening the vessel (see Step 4.3.1). These vessels shall have an internal volume of ' 500-600 ml and be equipped to accommodate a 90-110 mm filter. 'Fhe devices contain VITON°~ 0-rings which should be replaced frequently. Suitable ZHE devices known to EPA are identified in Table 3. I For the ZHE to be acceptable for use, the piston within the ZHE should be able to be moved with approximately 15 psi or less. :[f it takes more pressure to move the piston, the 0-rings in the device should be replaced. If this does not solve the problem, the ZHE is unacceptable for 1312 analyses and the manufacturer should be contacted. t The ZHE should be checked for leaks after every extracti~m. If the device contains a built-in pressure gauge, pressurize the de~~ice to 50 psi, allow it to stand unattended for 1 hour, and recheck the pressure. If the device does not have a built-in pressure gauge, pressurize the ' device to 50 psi, submerge it in water, and check for the presence of air bubbles escaping from any of the fittings. If pressure is lost, check all fittings and inspect and replace 0-rings, if necessary. Retest the device. If leakage problems cannot be solved, the manufacturer should be contacted. Some ZHEs use gas pressure to actuate the ZHE piston, while others '' use mechanical pressure (see Table 3). Whereas the volatiles procedure (see Step 7.3) refers to pounds-per-square-inch (psi), for the mechanically actuated piston, the pressure applied is measured in torque- ' inch-pounds. Refer to the manufacturer's instructions as to the proper conversion. 4.2.2 Bottle Extraction Vessel. When the sample is being evaluated using the nonvolatile extraction, a jar with sufficient capacity to hold the sample and the extraction fluid is needed. Headspace is allowed in this vessel. ' ~VITON® is a trademark of Du Pont. 1312 - 2 Revision 0 November 1990