Recommendation:
Store mobile phases in borosilicate glass reservoirs type 1,
class A
2
or type 3.3
3
. Use brown-stained glassware, to inhibit microbial growth. Use
aluminum foil or Waters caps to cover the reservoirs.
B.1.4 Water
Use water only from a high-quality water purification system. If the water system
does not deliver filtered water, filter the water through a 0.2-μm membrane filter.
Notice:
Using 100% water can cause microbial growth. Waters
recommends changing 100% water solutions daily. Adding a small amount
of an organic solvent (~10%) prevents microbial growth.
B.1.4.1 Using buffers
Adjust the pH of aqueous buffers. Filter them, to remove insoluble material, and then
blend them with appropriate organic modifiers. After you use a buffer, flush it from
the pump by wet priming using at least five system volumes of HPLC-grade distilled
or deionized water. When using a buffer, choose good quality reagents, filtering
them through a 0.2-μm membrane filter.
For shutdowns of more than a day's duration, flush the pump with a 20% methanol/
water solution, to prevent microbial growth.
Notice:
Some buffers can be incompatible with mass spectrometers.
Consult the documentation that accompanies your instrument for compatible
buffers.
See also:
For an explanation about how to prevent contamination, refer to
Controlling Contamination in Ultra Performance LC/MS and HPLC/MS Systems (part
number 715001307) on the Waters Web site. Visit www.waters.com.
B.2 Common solvent properties
The following table lists the properties for some common chromatographic solvents.
Table B–1: Properties of common solvents
Solvent
Vapor pressure mm Hg
(Torr)
Boiling
point (°C)
Flash
point (°C)
Acetone
184.5 at 20 °C
56.29
-20
Acetonitrile
88.8 at 25 °C
81.6
6
n-butyl acetate
7.8 at 20 °C
126.11
22
June 12, 2015, 715004747 Rev. A
Page 70