Waters XSelect CSH130 C18 3.5 μm and 5 μm Columns - Manual (Page 4)

[ CARE AND USE MANUAL ]
XSelect CSH130 C
18
Columns 4
d. Solvents
To maintain maximum column performance, use high quality chromatography
grade solvents. Filter all aqueous buffers prior to use. Pall Gelman Laboratory
Acrodisc
® filters are recommended. Solvents containing suspended particulate
materials will generally clog the outside surface of the inlet distribution frit of
the column. This will result in higher operating pressure and poor performance.
e. Pressure
XSelect CSH130 C
18
columns can tolerate pressures of up to 6,000 psi
(400 bar or 40 Mpa) although pressures greater than 4,000 – 5,000 psi
should be avoided in order to maximize column and system lifetimes.
f. Temperature
Temperatures up to 80 ˚C are recommended for operating XSelect CSH130
C
18
columns in order to enhance selectivity, lower solvent viscosity and
increase mass transfer rates. However, any temperature above ambient will
have a negative effect on lifetime which will vary depending on the pH and
buffer conditions used.
Table 2: Buffer Recommendations for Using XSelect CSH130 C
18
Columns from pH 1 to 11
Additive/Buffer pKa Buffer range Volatility
(±1 pH unit) Used for
Mass Spec Comments
TFA 0.3 Volatile Yes Ion pair additive, can suppress MS signal, used in the 0.02-0.1% range.
Acetic Acid 4.76 Volatile Yes Maximum buffering obtained when used with ammonium acetate salt. Used in 0.1-1.0% range.
Formic Acid 3.75 Volatile Yes Maximum buffering obtained when used with ammonium formate salt. Used in 0.1-1.0% range.
Acetate (NH
4
CH
2
COOH) 4.76 3.76 – 5.76 Volatile Yes Used in the 1-10 mM range. Note that sodium or potassium salts are not volatile.
Formate (NH
4
COOH) 3.75 2.75 – 4.75 Volatile Yes Used in the 1-10 mM range. Note that sodium or potassium salts are not volatile.
Phosphate 1 2.15 1.15 – 3.15 Non-volatile No Traditional low pH buffer, good UV transparency.
Phosphate 2 7.2 6.20 – 8.20 Non-volatile No Above pH 7, reduce temperature/concentration and use a guard column to maximize lifetime.
Phosphate 3 12.3 11.3 - 13.3 Non-volatile No Above pH 7, reduce temperature/concentration and use a guard column to maximize lifetime.
4-Methylmorpholine ~8.4 7.4 – 9.4 Volatile Yes Generally used at 10 mM or less.
Ammonia (NH
4
OH) 9.2 8.2 – 10.2 Volatile Yes Keep concentration below 10 mM and temperatures below 30 ˚C.
Ammonium Bicarbonate 10.3 (HCO
3 -
)
9.2 (NH
4 +
)
8.2 – 11.3 Volatile Yes Used in the 5-10 mM range (for MS work keep source >150 ˚C ). Adjust pH with
ammonium hydroxide or acetic acid. Good buffering capacity at pH 10
Note: use ammonium bicarbonate (NH
4
HCO
3
), not ammonium carbonate ((NH
4
)
2
CO
3
).
Ammonium (Acetate) 9.2 8.2 – 10.2 Volatile Yes Used in the 1-10 mM range.
Ammonium (Formate) 9.2 8.2 – 10.2 Volatile Yes Used in the 1-10 mM range.
Borate 9.2 8.2 – 10.2 Non-Volatile No Reduce temperature/concentration and use a guard column to maximize lifetime.
CAPSO 9.7 8.7 – 10.7 Non-Volatile No Zwitterionic buffer, compatible with acetonitrile, used in the 1-10 mM range. Low odor.
Glycine 2.4, 9.8 8.8 – 10.8 Non-Volatile No Zwitterionic buffer, can give longer lifetimes than borate buffer.
1-Methylpiperidine 10.2 9.3 – 11.3 Volatile Yes Used in the 1-10 mM range.
CAPS 10.4 9.5 – 11.5 Non-Volatile No Zwitterionic buffer, compatible with acetonitrile, used in the 1-10 mM range. Low odor.
Triethylamine
(as acetate salt) 10.7 9.7 – 11.7 Volatile Yes Used in the 0.1-1.0% range. Volatile only when titrated with acetic acid (not hydrochloric or phosphoric).
Used as ion-pair for DNA analysis at pH 7-9