Antec Leyden has developed integrated system solutions for the
analysis of (di-) sulfides such as (di-)glutathione, cystine/cysteine,
homocystine/homocysteine. An ALEXYS system has been used with
a DECADE II with dual cell control and a reactor cell for reduction
of disulfides to thiols. In the second cell thiols are detected
by oxidative amperometric detection.
R’-S-S-R” + 2 H+ + 2 e- --> R’SH + R”SH
Thiols as well as the oxidised free disulfides can be quantified
this way, which is not possible when a pre-column reduction
of disulfides is applied.Disulfides
- Both mono- and disulfides in one run
- Detection limit 20 fmol on column (10 nM/2µL)
Fig. 1. Analysis of 1 µM cystine (CSSC), cysteine
(CSH), glutathione (GSH), homocysteine (HCSH) and di-glutathione
(GSSG) standards (2 µL injection). Disulfides CSSC and GSSG
are not visible when switching off the pre-reduction cell
(blue trace).
Table 1. System Solutions for Disulfides
|
Part no.
|
Description |
|
180.0068A |
ALEXYS Disulfides 1 for RED-OX of (di-)sulfides |
For the analysis of disulfides we selected the Flexcell electrochemical
cell. This cell has an exchangeable working electrode which
is particularly useful in this application. The electrode material
tends to vanish over the years, in the process of amperometric
detection of thiols. Exchanging an electrode disc only
takes a few minutes. The HyREF is completely maintenance free!
The ALEXYS system comprises the following parts:
- AS 100 autosampler, cool
- LC 110 HPLC pump
- OR 110 organiser rack
- Clarity data acquisition software
- DECADE II electrochemical detector with DCC
- Flexcell with Au WE, HyREF
- Reactor with GC WE, HyREF
ALEXYS Disulfides II for homocysteine uses a standard HPLC
system, and a Flexcell with gold working electrode.
Table 2. Column for Disulfides
|
Part no.
|
Description |
| 250.1114 |
ALF-115, 150x1.0 mm ID,
3 µm, C18 (disulfides) |
| 250.1122 |
ALF-515, 150x4.6mm, 3um,
C18 (Homocysteine) |
- 211-004
- Analysis of glutathione and other (di-)sulfides
- 211-003
- Homocysteine in plasma
|
ALEXYS Disulfides 1
The system
uses 2 Flexcells in series for reduction of disulfides before
oxidative detection of monomers in the second cell.
|
