Waters Sep-Pak DNPH-Silica Cartridges - Manual (Page 8)

[ Care and Use ManUal ]
Waters Sep-Pak DNPH-Silica Cartridge
8
4. Arnts, R.R. and Tejada, S. B., “2,4-Dinitrophenylhydrazine-
Coated Silica Gen Cartridge Method for Determination of
Formaldehyde in Air: Identification of an Ozone Interference”,
Environ. Sci. Technol. 1989, 23, 1428-1430.
5. Guide to Successful Operation of Your LC System; Millipore
Corporation, Waters Chromatography Division: Milford, MA
1991. See Appendix E to order.
6. ASTM Method E411; Standard Test Method for Trace Quantities
of Carbonyl Compounds with 2,4-Dinitrophenylhydrazine.
VIII. orderInG InForMAtIon
Waters Sep-Pak DNPH-Silica cartridges are shipped in boxes of 20
individually-packaged cartridges. Pouches are supplied for storage
after sampling.
Table 6: Ordering Information
IX. APPendICes
Appendix A: Measuring Acetonitrile Purity
HPLC-grade acetonitrile may contain traces of aldehydes and
ketones, especially acetone. 10 µg/L of an aldehyde or ketone
in the acetonitrile adds 0.1 µg DNPH derivative per cartridge to
background values.
If your acetonitrile is unacceptable for your application, contact your
solvent supplier, or purify the acetonitrile. To purify acetonitrile,
distill it from an acidified DNPH solution using a procedure
analogous to the one described in ASTM Method E411 for the
purification of methanol
6 .
To measure acetonitrile purity:
1. Clean all glassware by rinsing with acetonitrile and heating in a
60 °C vacuum oven for at least 30 minutes.
2. Elute a fresh cartridge with 3 mL acetonitrile.
3. Within 3 minutes, inject the eluate onto the HPLC system to
measure the concentration of DNPH derivatives.
4. Add 1 drop of concentrated HCl to the eluate and allow it to
react at room temperature for 30 minutes.
Derivative Concentration (µg/mL)
Formaldehyde-DNPH 0.08
Acetaldehyde-DNPH 0.12
Acetone-DNPH 0.40
All other hydrazones <0.05
Derivative Concentration (µg/mL)
Formaldehyde-DNPH 0.09
Acetaldehyde-DNPH 0.14
Acetone-DNPH 2.00
All other hydrazones <0.05
Derivative Concentration
after Reaction
with Acid
Minus
Concentration in
Blank
Equals
Contribution from
Acetonitrile
Formaldehyde-
DNPH 0.09 µg/mL - 0.08 µg/mL = 0.01 µg/mL
Acetaldehyde-
DNPH 0.14 µg/mL - 0.12 µg/mL = 0.02 µg/mL
Acetone-DNPH 2.00 µg/mL - 0.40 µg/mL = 1.60 µg/mL
Derivative Contribution
from
Acetonitrile
Divided by
Background
Value
Times 100 Equals Percent
Relative to
Background
Formaldehyde-
DNPH 0.01 ч ч 0.08 x 100 = 12%
Acetaldehyde-
DNPH 0.02 ч ч 0.12 x 100 = 17%
Acetone-DNPH 1.60 ч ч 0.40 x 100 =
400%
Product Part Number
Sep-Pak DNPH-Silica Cartridges, 20/
box WAT037500
Sep-Pak DNPH-Silica Long Body
Cartridges, 20/box WAT039550
Nova-Pak C
18
Column, 3.9 x 75 mm WAT011670
Nova-Pak C
18
Column, 3.9 x 150 mm WAT086344
In-line Pre-Column Filter (0.5µm) 600000180
HVLP Mobile Phase Filter, 100/pkg WAT200530
Beginners Guide to Liquid
Chromatography 715001531
Ozone Scrubber Cartridge, 20/box WAT54420