Waters XBridge Peptide BEH C18 130A and 300A Columns - Manual (Page 4)

Table 2: Buffer Recommendations for Using XBridge Peptide BEH C
18
, 130Å and 300Å Columns from pH 1 to 12
Additive/Buffer pK
a
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
Pyrrolidine 11.3 10.3 – 12.3 Volatile Yes Mild buffer, gives long lifetime.
4
[ CARE AND USE MANUAL ]
XBridge Peptide BEH C
18
, 130Å and 300Å Columns