Introduction - Determination of Anions in Natural and Treated Waters - page 45

performance liquid chromatography instruments, the greatest sensitivity is obtained using
the Alpha Plus instrument with ion exchange separation and post-column derivatisation
with OPA reagent (108µg) or the high performance liquid chromatography instrument
using reversed-phase chromatography and pre-column derivatisation with OPA, or
fluorenyl methoxycarbonyl chloride reagents (30-33ng).
One leading supplier, LKB, is discussed below. LKB supply two instruments, the LKP
4150 Alpha HPLC, and for analysis requiring higher sensitivity and faster run times the
LKB 4151 Alpha Plus.
LKB 4150 Alpha
This system is a reversed-column chromatograph equipped for pre-column derivatisation.
The column is made of glass and has solid-state heating. The detection system
compromises a dual-channel photometer with a high-temperature reaction coil. A single
low-volume long-pathlength flow cell is employed. A fluorescence detector is available
to
Fig. 1.4 Chromatogram of amino acid mixture: sample physiological fluid
amino acid standard, 10nmol amino acid in 40µL column—LKB
4418-550 high-resolution column, 270×4.6mm packed with lithium
from exchange resin; buffers—physiological fluid buffer system (five
lithium buffers); flow rate—20mol h −1 ninhydrin; detection—vis.
570nm and 440nm, 1.0AUFS
Source: Own files
provide an approximately 10-fold increase in sensitivity over ninhydrin detection.
Refrigerated sample capsule loading is supplied. Powerful programming capability
permits the storage of up to 200 methods. Storage facilities for six buffers is supplied.
LKB 4151 Alpha Plus
Alpha Plus is a fully automated and dedicated analyser. This turnkey system has been
carefully designed to give a truly robust chromatography. Stepwise elution with up to five
buffers plus flexible temperature control guarantees optimal separations from even the
most complex samples. The versatile programmer monitors and controls all instrument
functions and a complete fault-detection system assures absolutely safe operation while