ADV06-15_1-412

15 / 413

Feedback? E-mail 13
Recondensed
solvent
Liquid
sample
Glass
wool
Solvent
vapors
Bottom of
the liner
High ow
Rxi® retention gap
Carrier gas
Sky® inlet liner
Analytical column
Figure 1: How it Works: The CSR-LVSI Setup.
1. Clean, interference-free extracts from samples are produced using
Resprep® SPE cartridges.
2. A fast autosampler injection with liquid band formation is used to make
large volume injections.
3. The liquid sample enters a 4 mm Sky® inlet liner containing deactivated
quartz glass wool at the bottom. The wool is critical since it acts as a
“solvent reservoir.” It also enhances vaporization and improves
injection-to-injection reproducibility.
4. Rapid solvent evaporation occurs in the hot inlet, causing a pressure surge
and a high rate of flow onto an Rxi® retention gap (precolumn), which is
attached to the analytical column using a press-fit connector.
5. Because the starting oven temperature is below the boiling point of the
solvent, solvent recondensation occurs in the retention gap at the same
rate that evaporation occurs in the inlet, driving the rapid transfer of
material to the column and preventing backflash.
6. Higher boiling point solutes transfer to the retention gap after the solvent
transfer, and are trapped by the recondensed solvent film.
7. After total sample transfer to the retention gap, the oven temperature ramp
evaporates the solvent, focusing the analytes into a narrow band prior to
analysis on the analytical column.
Starting Parameters for
Dichloromethane Injection Volumes
Injection Vol.
(µL)
Precolumn
(m x mm ID)
Wool in liner
(mg)
≤ 12.5 5 x 0.25b 5a
≤ 25 5 x 0.53 5
≤ 50 10 x 0.53 10
250 30 x 0.53c 10
aStandard single taper liner with wool, ban Integra-Guard®
column may be suitable, c30 m segments of guard columns
may require a custom order
Table I: Starting points for CSR-LVSI
method optimization.
Figure 2: While large volume injections extend analysis times, using CSR-LVSI
for drinking water contaminant analysis provides good sensitivity without the
expense of a PTV inlet.
References
[1] P. Magni, T. Porzano,Concurrent Solvent Recondensation
Large Sample Volume Splitless Injection, J. Sep. Sci. 26
(2003) 1491.
[2] Patent No: US 6,955,709 B2.
[3] J. Cochran,The Solvent Effect in Concurrent Solvent
Recondensation Large Volume Splitless Injection with
Methylene Chloride – EPA Method 8270 Semivolatiles,
ChromaBLOGraphy, Restek Corporation, 2011
(accessed March 2, 2012).
[4] M. Misselwitz, J. Cochran,Large Volume Splitless Injection
Using an Unmodified Split/Splitless Inlet and GC-TOFMS
for Pesticides and Brominated Flame Retardants,
Application Note EVAN1331-UNV, Restek Corporation, 2011.
[5] C. Rattray, J. Cochran, C. English, Lowering Detection Limits
for 1,4-Dioxane in Drinking Water Using Large Volume
Injection in an Unmodified Splitless GC Inlet,Application
Note EVAN1548-UNV, Restek Corporation, 2012.
[6] C. Rattray, J. Cochran, Combined Determination of
1,4-Dioxane and Nitrosamine Contaminants in Drinking
Water Using a Single SPE Cartridge and Concurrent Solvent
Recondensation–Large Volume Splitless Injection
(CSR-LVSI) With EI GC-MS, Application Note
EVAN1922A-UNV, Restek Corporation, 2014.
10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00 18.00
50 µL injection, 5 ng on-column
Time (min)
1
2
3
4
5
6
7
8
9
GC_EV1342
5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00
1
2
3
4
5
6
7
8
9
Time (min)
10 µL injection, 5 ng on-column
GC_EV1345
Peaks
1. Tetrahydrofuran
2. 1,4-Dioxane
3. N-Nitrosodimethylamine
4. N-Nitrosomethylethylamine
5. N-Nitrosodiethylamine
6. N-Nitrosopyrrolidine
7. N-Nitrosodi- n-propylamine
8. N-Nitrosopiperidine
9. N-Nitrosodi-n-butylamine
Column: Rxi®-5Sil MS, 30 m, 0.25 mm ID, 1.00 µm (cat.# 13653) using Rxi® guard column 10 m, 0.53 mm ID (cat.# 10073) with BGB P/N:
2553LD; Sample:1,4-Dioxane (cat.# 30287), Nitrosamine calibration mix, Method 521 (cat.# 31898), Tetrahydrofuran (THF) (cat.# 30414);
Diluent: Dichloromethane; Liner (for CSR-LVSI): Custom Sky® single taper with 15 mg quartz wool; Liner (for standard injection): 4 mm Sky®
single taper w/wool (cat.# 23303.5); Inj. Temp.: 275 °C; Purge Flow: 100 mL/min;Oven: (for CSR-LVSI): 35 °C (hold 1.5 min) to 50 °C at 50 °C/
min (hold 7.1 min) to 320 °C at 11.12 °C/min (hold 1.5 min); Oven: (for standard injection): 35 °C (hold 1.5 min) to 50 °C at 50 °C/min (hold 2.02
min) to 320 °C at 11.12 °C/min (hold 1.5 min);Carrier Gas: He, constant flow; Flow Rate: 5.08 mL/min; Detector: MS; Mode: SIM; Transfer
Line Temp.: 320 °C; Analyzer Type: Quadrupole; Source Temp.: 230 °C; Quad Temp.: 150 °C; Ionization Mode: EI;Instrument: Agilent 7890A
GC & 5975C MSD. Notes: For SIM program and other conditions, visit and enter GC_EV1342 and GC_EV1345 in the search.
*Toluene contaminant
*
*