DOC-Labor
Dr. Stefan Huber
Specifications

Energy consumption
0.4 kWh
Environment temperature
18 - 30 °C (stable temperature 1 °C is required for high-sensitivity)
DOCOX/DONOX reactor
2 x 900 V / 40 mA (one transformator)
Thin film reactor
990 V / 160 mA
Carrier gas
Nitrogen 4.0 or 5.0, about 12 L/h
Mobile phase
Phosphate buffer STD = 28 mmol, pH 6.58, about 2 L in 24 hrs
Acidification solution
Phosphoric Acid pH 1.5, about 0.8 L in 24 hrs
Measuring range DOC (bypass)
<1 - 5000 ppb
Measuring range LC-OCD
>1 - 5000 ppb
Detection limit LC-OCD
<1 - 50 ppb (compund-specific)
Smaller footprint. (60x60 cm)
Organic Nitrogen Detector (OND) is now an integral part of the system
Less components (e.g. 1 HPLC-pump instead of 3 pumps is required)
Reduced analysis time (from 3 hrs to 2 hrs or less = 12 samples/day instead of 8 samples/day)
Autosampler with 36 positions for uninterrupted 5-day operatio
10 L mobile phase flask allows unattended operation of systems for 5 days (120 hrs)
System may be used as process instrument for quasi-continous on-line monitoring
Much more simple operation of system ("One-Button-Instrument")
40% higher sensitivity for OCS (detection limit < 1 ppb)
40% less consumption of electricity (only 350 VA)
30% less consumption of nitrogen carrier gas (only 200 scm/min).
A 50-L bottle lasts for about 5 weeks
Manual injection device for ”quick” TOC-measurements during standard operation
Software for data acquisition and autosampler is now custom-made by Doc-Labor on LabView basis
Except for Windows Office no additional software is required
External ports for additional detectors (e.g. fluorescence) and fraction collector
Last not least: The new system looks much better than its precursors
New Model 8 LC-OCD-OND System

Pros and Cons to older systems


The new system, called "LC-OCD Model 8" has the following advantages:
The only disadvantage of ”Model 8”:

The ”TOC”-parameter is not anymore measured during standard operation. Only ”DOC” is measured.

Why?? Mainly out of 3 reasons:






Nevertheless, there is still the option to measure TOC manually.
For correct analysis of POC (Particulate Organic Carbon) samples have to be homogenised immediately prior to injection. For automated operation this would require stirring bars and magnetic stirrers for each vial port. Such a feature would be extremely costly to realise.
The UV-detector (254 nm) has a built-in narrow capillary which may get blocked.
our UV-based oxidation process may not be able to oxidise POC fully (for particles the UV-exposure time of 3 min in the thin film reactor may not be sufficient).