Water is the prerequisite for life on our planet. In times of
growing environmental problems the measurement of the
water quality as well as for solids such as soils are vital.
The measurement of all organic pollutants by means of their
content of organically bound carbon (TOC) serves as the
analysis method for fast and highly sensitive determination
of the total pollution load.
Crucial advantages compared to the classical wet chemical
Chemical Oxygen Demand (COD) procedures are:
Decrease of the analysis time from hours to minutes
Omission of pollutants like Cr
Completely safe and automatic operation
No measuring result falsification by inorganic
Additional possibility to measure bound nitrogen
) instead of the also environmentally problem
atic Kjeldahl method
As the successor of Heraeus, Elementar has a more than
100 years tradition in developing and manufacturing analy
zers for the “organic“ elements such as carbon and nitrogen
by means of high temperature digestion.
This concept was already used in 1976 in the first fully auto
matic TOC analyzer. The vario TOC cube is the very latest
development of TOC/TN
analyzers by Elementar. This top
advanced water analysis with the elemental analysis of sol
ids based on the special experience of Elementar for both
these areas of instrumental analysis.
Liqui TOC 1976 (Heraeus)
Clean analysis for a clean environment
digestion of the sample in an air/O
stream at 850°C. For
temperatures of permanently up to 1200°C or temporarily
1800°C can be achieved. Totally bound carbon is converted
which is quantitatively determined by means of a
NDIR detector. The advantage of this method as opposed
to the wet chemical UV/persulfate digestion is the absolute
assurance that even stable compounds, particles or salt
containing solutions will be completely detected. Addition
ally the high temperature method makes the determination
of bound nitrogen (TN
directly injected into the combustion tube where cata
lytic oxidation takes place. Alternatively, solid samples are
inserted via a ball valve. Water vapor is removed in a 3stage
drying process, “rock steady” flow rate is maintained in the
presence of varying pressure conditions by a digital mass
flow controller, resulting in the most accurate measure
ment of the total carbon (TC) content by NDIR detection.
A connected PC calculates the carbon content from the
sample volume and/or weight and the detector signal based
on a calibration curve.
Inorganic carbon (carbonate), may be automatically deter
mined as TIC after acidification and purging in the sparger.
The TOC is calculated from TCTIC. A direct non purgable
organic carbon (NPOC) determination is also possible after
external TIC removal (typically in the sample carousel). The
sparger may also be used for direct determination of pur
gable or volatile carbon compounds (VOC or POC). Thus, all
relevant parameters of TOC analysis are accessible with one
instrument and without extensive modifications.
The use of NO specific detectors extends the application
area to the TN
analysis of bound nitrogen. The total con
a minimum number of valves. This results in shorter analysis
times, lower detection limit as well as the ability for measure
ment of particle and salt containing samples.
The basic concept decides
samples. Quartz ash crucibles are used for the separation
and collection of combustion residues. The combustion
takes place in the crucible, and non volatile or incombustible
materials, such as salts, remain behind. This is the first use
of ash crucibles for matrix separation in TOC determinations
(patent applied for). Thus, contamination of the catalyst can
be prevented and the residues can be easily removed from
the crucible. Therefore it is possible to work above the melt
ing point of NaCl.
Long term stability and high sample throughput are impera
tive if TOC analysers are to be effectively used for screen
ing purposes. The vario TOC sets new standards in this
regard. Even with large injection volumes the highly effective
3stage drying system is working almost maintenance free.
Fluctuations in the gas stream caused by sample injection
and evaporation are controlled with a flow regulation device
(FRC). The ability to separate sample matrices from analyzed
gases results in long uninterrupted measuring periods even
for highly contaminated samples.
NDIR detection of the next generation
A completely new high performance detector for CO
persive infrared (NDIR) principle means a minimization of
spectral interferences and a vastly lownoise characteristic.
A dynamic detection range for TOC from ppb into the per
centage range is achieved by the 24 bit digital resolution of
the measuring signal without the need for measuring range
gain adjustments. Unique is the possibility to also measure
The vario TOC has the capability for integrated automatic
sample feeding of liquids, particulate containing liquids,
semisolids and even solid samples. For liquid samples the
well proven digitally controlled syringe aspirates all aliquots
of sample required for the number of replicates from the
sampler vial all at once. The transfer tubing is rinsed with the
sample itself, and then each aliquot is sequentially injected
into the combustion tube. This procedure eliminates repli
cate variability due to atmospheric CO
after the septum is
multipoint calibrations from just one calibration solution
over a very large dynamic range. Analyses of particulate
containing samples benefit from a single ceramic manifold
valve and short tubing paths.
For solid sampling, Elementar has incorporated its well
proven solid sampling technology utilized in organic elemen
tal analysis. The samples are weighed into tin capsules and
automatically transferred to the combustion tube via the pat
ented ball valve of Heraeus. This allows for virtually any type
of sample to be analyzed, from just a few µl of a liquid, large
particulate containing samples, semisolids to actual solid
samples. Automatic sample feeding of up to 120 samples is
possible, with analysis times of only 23 minutes.
A high combustion temperature is vital for a quantitative oxi
dation of bound carbon to CO
and a precondition for the
cube can be operated at a permanent furnace temperature
of up to 1200°C. In solids mode the combustion enthalpy of
the tin capsules results in a temporary temperature increase
Superior – the sum of the Good
conditions of the analyzer in both numerical and graphical
forms, easy and efficient input of run information with auto
mated functions, cut and paste data to or from Excel, as well
as statistical analysis options.
The system is designed for intuitive operation, but content
sensitive help is just a click away. Automatic optimization
of parameters, monitoring of maintenance intervals and ser
vice messages, LIMS data transfer are all integrated into the
system. Graphical leak checking with pictorial guides for
each step are a new favorite feature of users.
We also feature our unique browser based 3D pictorial parts
list, with drill down operation and exploded component
Data safety and validity can be assured with the available
21 CFR Part 11 compliant option.
The vario TOC cube design utilizes the latest micro elec
tronic technology in which all instrument functions are digi
tally controlled and monitored. This results in completely
new possibilities in automatic operation, optimization as well
as remote control and diagnosis over the internet.
The basis for this is the use of a new micro processor gen
eration with 24 bit signal processing and electronic sensors
for all gas flows and pressures.
The vario TOC cube‘s firmware (internal software of the
analyzer) is stored on flash EPROMS, which can be easily
updated via PC or the internet. The critically important fast
signal communication between components in the analyzer
(such as the detector signal) is handled by the failsafe CAN
A commercial PC or laptop serves as the user interface for
control and evaluation. Our software runs under the Win
dows operating system and offers features and capabilities
too numerous for a complete listing here.
Design and operation of the Windows based software is a key
component of our whole system. The vario TOC cube soft
ware is written and developed at our own premises by our
own personnel according to strict ISO 9001 requirements.
Micro electronics as the decisive factor
River particulate (Elbe)
Soil standard 1 (3.5% C)
Langbeinite with additive
Brine (36 % NaCl / 1:1)
Nitric acid (approx. 5%)
Standard (100 ppb)
matrix separator. A special TIC only mode is very useful for
sea water analysis.
Highly concentrated solutions
Brine is a saturated (36%) salt solution from processes like
chlorine alkaline electrolysis. After a 1:1 dilution it is possible
to measure 200 samples in series and to determine safely
even 1 ppm TOC. Natural brine with 9.5% dissolved mineral
content is one of the most concentrated in Germany and has
a natural high turbidity. Even diluted mineral acids can be
safely measured with vario TOC cube.
The integrated sampler in connection with the high temper
ature combustion allows TC analyses with tin capsules of
up to 120 samples. Samples can range from true solids to
heavy slurries to pasty semisolids. This technique can also
be used for liquid samples in which only a limited quantity
exists (even several µl’s). Carbon can even be determined
from thermally stable carbide ceramics with a decomposi
tion temperature of 1800°C with a 100% recovery.
vario TOC makes it possible to determine the chemically
bound nitrogen (TN
) which is gaining more interest in water
There are 3 detectors available for the detection of the
formed NO. Using a NDIR detector, for example, a standard
deviation of 13 ppb at 100 ppb as well as a large concentra
tion range up to more than 50,000 ppm can be attained.
In connection with an injection volume of 2 ml the highly
sensitive NDIR detector allows the analysis of water quali
ties for pharmaceutical applications. A standard deviation
of 6 ppb (3 ppb trace) for a concentration of 70 ppb signifi
cantly exceeds the requirements of the Pharmacopoeia.
Even with high carbonate contents a very low TOC value
is precisely measurable after acidification and purging of
the TIC. Comparable conditions can also be found for well
Water from rivers and lakes do not represent any difficul
ties for the vario TOC cube. Particles and suspended solids
which are commonly present in these samples can be mea
sured directly without any problems.
The large dynamic measuring range offers advantages for
strongly fluctuating TOC concentrations in municipal waste
water. Even waste water from circuit board processing with
high electrolyte contents such as sulphates are measured
correctly due to the matrix separation and interferencefree
The salt content of the oceans is approx. 3.5% whereas the
TOC content lies in the lower ppm range. The vario TOC
cube is able to peform over 100 precise TOC measurements
Even if it gets really tough
vario TOC cube represents a complete line of TOC analyz
ers which can be configured for the individual user require
ments. The modular system is based on a basic instrument
which already includes the main functions:
Automatic dosing and distribution of liquid samples
Sparger for stripping of TIC as CO
TC/NPOC or POC (VOC) to CO
Measuring gas drying and gas flow regulation
detection in the carrier gas stream
Instrument operation, control and measuring value
processing is done via a connected PC or laptop
In connection with the basic instrument there are a variety of
modules available to achieve various applications.
Selection of liquid sample feeding
Different modules allow the measurement of liquids either
in single mode or with an automatic sample feeder for either
32, 50 or 80 samples. The sampler for 32 samples is espe
cially suitable for 40 ml septum vials according to EPA. The
sample can be stirred in each of the operation modes. Air
purging for stripping TIC or POC (VOC) is also possible. All
types of samplers will be integrated in the instrument and
do not require any additional footprint. Random access to
selected sample positions is also a feature of vario TOC auto
Selection of solid sample feeding
Different modules enable the measurement of samples in tin
foils or capsules, either in single mode or with an automatic
sampler for 80 or 120 samples. This is suitable for solid
samples but can also be used for heavy particulate contain
ing samples, viscous liquids, semisolids or liquid samples
of very small quantity. Sample as large as 300 mg can be
accomondated in the 120 position sampler, and up to 1 g in
the 80 position sampler.
The user can easily and quickly reconfigure the vario TOC
cube between liquids or solid sampling.
Selection of the detections
Three different NDIR detectors are available for carbon
A standard wide range NDIR detector is suitable for
almost all applications
A trace version NDIR with double cuvette length is
available for lowest detection limits.
For very high carbon concentrations e.g. in solids, a
special optional detector is available
The content of bound nitrogen (TN
) can be optionally mea
Electrochemical cell (EC) as the most economic
Chemiluminescence detector (CLD) according to
DIN 38409 H27
Non dispersive IR detector for largest concentration
range from 0.05 to more than 50,000 ppm.
vario TOC cube – literally variable
Catalytic high temperature combustion at 850°950°C (max. 1200°C)
Oxidation from C to CO
which is quantitatively determined with a NDIR
TC, TOC, DOC, NPOC, TIC, POC, optional TN
Norms and standards:
European Pharmacopoeia 6.0, vol.1 (20244) 2008, p. 71,
U.S.PharmacopoeiaNF, USP 30 (643) 2007; DIN 38409
CE, IEC 1010, EMV
6 µg/l (ppb)
(3 µg/l (ppb) for trace version)
0,02 mg/l (ppm)
at > 5 mg/l C
34 min per parameter
exceeds the requirements EN 1484 for 100 µm cellulose standard,
with capsule technique no upper limit
Specifications vario TOC cube
Automatic multi point calibration
liquid samples manual
solid sample manual
automatic sampler for liquid samples with
32 (40 ml), 50 (12 ml) or 80 (6 ml) positions
all positions can be stirred
automatic sampler for solid or particles containing samples
with 120 or 80 positions depending on sample size
Operation and control via PC under Windows®;
All instrument functions are digitally controllable, the comprehensive operation
software includes e.g. automatic leak test, extensive error diagnosis, monitor
ing of the maintenance cycles, sleep/wake up function, statistical evaluation
and almost unlimited memory capacity for analysis data incl. graphics.
Integration in data networks like LIMS and the possibility of
In full compliance with 21 CFR Part 11 (option).
Synthetic air (hydrocarbon and CO
free) or oxygen (4.5), 200 ml/min
100/110/200/230 VAC, 50/60 Hz, 1.8 kW
48 × 55 × 57 cm (w × d × h)
approx. 60 kg
Isotope ratio analysis (IRMS), ceramics, etc.
Pure water, surface water, drinking water, well water, brine, etc.
Industrial and municipal waste water, sewage sludge, solid waste, etc.
Injection water, cleaning validation, process water, etc.
Sediments, suspended particles, sea water, glacier water, carbonate rock
Galvanic baths, brine, Bayer Liquor, salt, etc.