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Improved SPE Cartridges for Massachusetts EPH Analysis
Monitoring Environmental Petroleum Hydrocarbons by SPE/GC
By Lydia Nolan, Innovations Chemist
• New MassachusettsTPHSPE cartridges reduce ext ractable contaminants and assure mo re reliable fractionation.
• Large un ifo rm lots of silica reduce frequ ency of verifying fract iona tion results.
New packaging reduces coextractables, provides better protection from humidity.
Concern about the effects of mat erials from leaking underground petroleum storage tanks has grown over the last ten years. In addi
tion to the US Environmental Prot ection Agency and international groups , several US states, including Massachusetts! and Texas>,
have developed methods for analyzing samples from their geograp hical areas. Because of the broad and thorough nature of the quan
titative information generated by the Massachusetts Department of Environmental Protection method', many site managers and
engineering firms outside of Massachusetts request this method for their samples.
Most frustrating for labs using this method has been the uniformity of commercial silica gel-con taining solid phase extraction (SPE)
cartridges used to prepare the samples for analysis. The activity level and capacity of the silica, the uniformity of the bed, and the
quality of the cartridge components and packaging are critical toward good results. Slight variations in the silica mat erial, or in
humidity levels during manufacture of the cartridges, can have a dramatic effect on the hexane fraction ation results. The volume of
hexane required to fractionate the aliphatic portion of the sample, without allowing any aromatic analytes to break thr ough into the
hexane fraction , can vary,typically from 17mL to 20mL
±
O.5mL, and must be determined for every lot of cartridges. Trace levels of
phthalates and other contaminants from cartridges, frits, and packaging are easily extract ed with the desired analytes, complicating
Figure 1 Low levels of background ext ractables in new Restek Massachusetts TPH SPE cart ridges.
40
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1.
o-terphenyl (20ng on column)
2. 1-chlorooctadecane (20ng on column)
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(A) Blank (no extraction)
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(B) Massachusetts TPH SPE cartridge
from current production process
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Massachusetts TPH SPEcartridge
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from former production process
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40 min.
GC_EV00816
Column:
Rtx~-5
30m, 0.32mm
!D,
0.251lm
(cat. #10224)
Sample:
50J-lLdiluted MAEPHSurrogate SpikeMix (cat.# 31479)(dilutedto400J-lg/ mL)
Inj.:
O.5J-lLsplitless(hold0.75min.), Precision" split inlet liner with wool (cat.# 21027)
Inj. temp.:
290°C
Inj. press. proq.: pressure pulseto 50cm/sec.
@
-0.71min. pressure to 35cm/ sec.
@
0.8min.
Carrier gas:
helium
Linear velocity: 35cm/ sec., constant velocity
Oventernp.:
40°C(hold 1 min.) to 310°C
@
15°C/ min.
Det.:
PerkinElmer AutoSYS'· GC-FID
@
330°C
2006
vol.
1
• 4 •
Website :
www.chromtech.net.auE-mail :
info@chromatech.net.auTelNo : 03 9762 2034 . . . in AUSTRALIA