Transcript SOLID PHASE EXTRACTION

ENVIRONMENTAL
ANALYSIS
I. Solid Phase Extraction
sorbent configurations –
layered phases
Sorbent Configurations
to Enhance Selectivity

Stacked phases

Layered phases

Mixed phases
Role of Layered Phases

Extending the range

Enhancing the selectivity

Separate cartridges not required
Layered Phases (Loading)
Small,
polar
C2
ENV+
Large, nonpolar
C2
ENV+
Broad Range
C2
ENV+
Layered Phases (Eluting)
Large, nonpolar
Small,
polar
ENV+
C2
ENV+
Broad Range
C2
ENV+
OC Pesticides from Water
Extraction on Layered Phases
ISOLUTE® C2 / C18(EC)
Sample pre-treatment
Column solvation
Column equilibration
Sample application
Interference elution
Analyte elution
HCl to pH=2,
Methanol, 0.5%
5 mL Methanol
10 mL reagent water
One liter in 1/2 hour
10 mL water, 10 min N2
Two x 2 mL THF
OC Pesticides from Water
Percent Recovery
Pesticides
C18(EC)
C2
C18(EC)
SUM
Aldrin
73
85
0
85
4,4’-DDE
62
86
5
91
Endosulfan II
78
65
37
102
AVG
88
54
43
97
17 pesticides
Interference Removal
Analyte
+
Interferences
Organic Elution Solvent
Interferences
(e.g., Humic Acids)
Interferences
Retained
NH2
NH2
ENV+
ENV+
Analytes
(e.g..., PAHs)
Analytes
Eluted
Extraction of PAHs from
Natural Waters
Extraction of analytes such as
PAHs from natural waters, can be
problematic due to co-extracted
humic and fulvic substances that
can interfere with the final analysis
technique.
PAHs and Humic Acids
[ R - CH - C OO ]
n
“Humic Acid”
Naphthalene
Benzo[a]pyrene
ISOLUTE PAH
ISOLUTE PAH is designed to alleviate
this problem. It consists of a layer of
NH2 sorbent above a layer of C18.
The NH2 layer (positively charged at
neutral pHs) retains the acidic
interferences,
while
PAHs
are
retained by and eluted from the C18
layer.
ISOLUTE PAH
Analyte
+
Interferences
Organic Elution Solvent
Interferences
(Humic Acids)
Interferences Retained
NH2
NH2
C18
C18
Analytes
( PAHs)
Analytes
Eluted
SPE Conditions
ISOLUTE PAH Column (NH2/C18)
10% IPA
1.
2.
3.
4.
5.
6.
Sample pre-treatment
Column solvation
Column equilibration
Sample application
Interference elution
Analyte elution
5 mL IPA
(AN 1025)
2 x 3 mL THF:nC6 (1:1)
5 mL 2% IPA in water
One liter in 30 to 60 min.
Bottle wash required.
5 mL water/IPA 9:1
15-30 min drying
HPLC Conditions
Column
HiChrom PAH2 (150x4.6mmx5m)
Mobile phase
A= ACN/Water (30/70, v/v)
B= 100% ACN
Gradient
100% A to 100% B in 35 mins.
100% B for 3 mins
Flow rate
1 ml / min
Detection
UV, 254 nm
20 l sample injected
HPLC chromatogram of blank river
water with a high humic acid
content extracted using C18 only
HPLC chromatogram of blank river
water with a high humic acid content
extracted using ISOLUTE PAH
HPLC Chromatogram of 16 PAHs extracted
from river water with a high humic acid
content using ISOLUTE PAH
PAH
Recoveries
Naphthalene
62 (13.8)
Acenaphthylene
73 (9.5)
Acenaphthene
98 (2.1)
Fluorene
82 (3.6)
Phenanthrene
94 (1.6)
Fluoranthene
84 (2.8)
Anthracene
101 (2.0)
Pyrene
92 (3.1)
Benzo(a)anthracene 99 (3.5)
Chrysene
100 (3.6)
Benzo(b)fluoranthene 94 (4.1)
Benzo(k)fluoranthene 95 (4.4)
Benzo(a)pyrene
96 (3.5)
Indeno(123-cd)pyrene 98 (1.2)
Dibenz(ah)anthracene 92 (2.7)
Benzo(ghi)perylene
92 (3.1)
Average: 91 (4.0)
ISOLUTE PAH HC



clean-up of HEXANE extracts of
oil contaminated soil
designed to separate the
aromatic PAHs from hydrocarbon
interference (up to C30)
clean baseline in GC analysis
PAH Method (IST AN 1070A)
SPE clean-up using ISOLUTE PAH HC, 1g / 3ml
Action
Method
Column conditioning /
equilibration
Condition columns with hexane
(8ml) at 2ml / min
Sample loading
Load 0.5ml of sample in apolar
solvent (hexane, i-octane)
Interference elution
Rinse column with pentane
(3ml) at 0.5ml / min
PAH elution
Elute PAHs with 2-propanol
(isopropanol) / hexane (3.4 ml
in 100ml, v/v), 6ml at 1ml / min
ISOLUTE EPH Column

fractionate pentane or hexane extract
of oil contaminated soil

designed to separate the C10-C22
aromatics from C8-C40 aliphatics

proprietary blend of silica / alumina

based on MADEP procedure
PAH Method (IST TN 142)
SPE clean-up using ISOLUTE EPH-M, 5g / 20ml
Action
Method
Column conditioning /
equilibration
Condition columns with hexane
(20ml) under gravity flow
Sample loading
Load (max) 1ml of sample in
heptane or hexane
Aliphatic elution
Elute aliphatics with 12ml of
hexane
PAH elution
Elute aromatics with 20ml of
DCM