Good to know, that it‘s going to be a good harvest next year

---

rapid N cube

---

Good to know, that it‘s going to be a good harvest next year.

2

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Die Kunst der Elementaranalyse

rapid N 1970 (Heraeus)

Nitrogen is one of the building blocks for proteins and 

therefore our basis for life. The precise nitrogen analysis is 

of vital importance not only for the determination of raw 

protein in food and feed but also in connected areas like 

soil fertility, fertilisers as well as biological and industrial 

materials. The superior reference method for the total ni-

trogen determination nowadays is the modified combus-

tion method according to Dumas which is applied in the 

rapid N cube. 

Compared to the traditional wet chemical method  

according to Kjeldahl there are remarkable advantages:

•  Decrease of the analysis time from hours to  

minutes

•  Completely safe and fully automatic operation

•  Omission of caustic and environment polluting  

chemicals

•  Low installation requirements and operating costs

•  100 % nitrogen recovery independent from the  

type of chemical bond

Elementar is the successor of the technology company 

 

Heraeus. With its more than 100 years of tradition in CHN 

analysis it was also the first manufacturer worldwide who 

made use of the Dumas method for macro samples up to the 

gram range. The ability to analyse large samples was essen-

tial for the use of the Dumas method for routine N/protein 

determination of every day samples.

The rapid N cube is the product coming from decades of 

experience. It incorporates modern micro mechanics, elec-

tronics and user oriented software.

The result is the most compact high performance instru-

ment for the Dumas nitrogen analysis, particularly suitable 

for cost efficient long term operation with minimum main-

tenance.

The analysis of sulfur is also possible as an option, another 

key element in biological systems.

Nitrogen analysis is elementary

Good to know, that it‘s going to be a good harvest next year.

3

---

The concept is impressively simple

Extreme lifetime optimises our instrument  

for the use in agrarian analysis.

4

---

The principle of the Dumas method for nitrogen determina-

tion is based on the quantitative combustion digestion of 

the sample at approx. 960°C in excess oxygen. The bound 

nitrogen is transferred into molecular nitrogen and nitric 

oxides. The analysis gases are transferred with CO

2

 as carrier 

gas via a catalytic post combustion zone onto a reduction 

zone. At this point, the conversion of the nitric oxides into 

nitrogen at hot tungsten takes place. Furthermore, the ex-

cess oxygen is bound. After a two stage drying phase, the 

gas mixture flows to the thermoconductivity detector (TCD) 

via an electronic flow controller. A connected PC calculates 

the nitrogen concentration in the sample from the TCD sig-

nal of the N

2

 in the CO

2

 and from the sample weight.

The design of the rapid N cube results in a very short flow 

path, minimal number of valves, moving parts and seal-

ings. This allows for a trouble-free long time operation. The 

measurement of all the analyte gas, without further sam-

pling or splitting, has several benefits. Errors due to com-

plicated aliquot valves are eliminated, there is no reduction 

in sensitivity due to a smaller amount of measured analyte, 

and there is no loss of analyte in the case of slowly com-

busting samples. The whole gas analysis further serves for 

automatic optimization of the analysis run and the oxygen 

consumption.

Using CO

2

 as carrier gas eliminates the need to absorb the 

CO

2

 generated from the combustion of the sample.

For the conversion to sulfur determination, the use of an 

optional high performance IR–detector allows the quick 

and precise analysis of sulfur as SO

2

 in the combustion 

gas. Since the furnace is already designed for the required 

1150°C, only the change from steel to a quartz glass combus-

tion tube is necessary.

The clear concept results in simple handling, cost-efficient 

operation and lowest installation requirements. The main-

tenance tasks are kept to a minimum.

Combustion

CO

2

O

2

Drying

Detection

CO

2

Ref.

5

---

Handling of macro samples

Up to 1 g solid sample material is wrapped in tin foil or  

paper and pressed into pellets. For liquids and suspensions, 

up to 0.5 ml (1 ml with special measures) is filled in tin cap-

sules and sealed gas tight with our optional liquid sampling 

press. This allows for the analysis of even inhomogeneous 

samples without extensive grinding or other pretreatment. 

Even up to 1 g of organic samples can be analysed!

High capacity autosampler

The wrapped samples are loaded into a carousel with 60 

positions. For samples up to approx. 300 mg weight there 

is also a carousel with 120 positions available. Reloading 

during operation is possible at any time. Carousel stacking 

which interferes with the reliability and inhibits continu-

ous loading while analysing, is not required. The samples 

are individually transferred to the combustion tube via the 

well proven ball valve. A new sealing technology has been  

employed. The system also incorporates a magnetically 

controlled shield to protect the ball value during the ener-

getic combustion process. 

The proven further improved

Optimal sample digestion

The 3-tube furnace is controllable up to 1200°C and there-

fore can be used not only for N analysis but also for the 

analysis of sulfur. The combustion for N analysis is done 

in the robust stainless steel combustion tube. A large and 

easy to change crucible collects the ash residues. Catalytic 

post combustion and reduction both take place in separate 

and voluminous reactors. Oxygen jet injection directly at the 

place of combustion serves for a 100 % oxygen dosing to the 

sample – even with strong combustion gas evolution. 

 

 

This results in minimal use of high purity oxygen together 

with more effective combustion. The patented use of tung-

sten for the reduction allows 2 to 3 times higher sample 

capacity in comparison to copper. This results in long un-

interrupted operation times. The furnace is designed to 

use low voltage, providing higher safety and also allows a 

10 year furnace warranty. Special attention has been paid 

to the air flow in the furnace compartment to avoid over  

heating damage even in the event of loss of cooling fans 

due to a power failure.

 

6

---

Stable gas control and high  

measuring dynamics

When combusting large sample weights, large pressure 

fluctuations and amounts of humidity may occur. Therefore, 

the analysis gases are led through an effective 2–stage gas 

drying and electronic gas flow control directly before the 

detector. The gas paths are reduced to an absolute mini-

mum and are made of non-corrosive material. 

 

The TCD has a large dynamic range for measurements ex-

tending from the ppm level to 100 %. The TCD is based on 

thermistor technology, is impervious to damage from oxy-

gen intrusion, and stands out for particularly high stability 

and measuring dynamics. Measurements below 20 ppm are 

possible and instrument calibrations are stable for months 

and even years.

0,00

0

107317.10

peak area (x)

µg N (y)

0

8000

7000

6000

5000

4000

3000

2000

1000

0

40

80

120

160

200

t[s]

TCD-Signal

75299.0

Peakgrafik glutamic acid

N calibration entire range

7

---

Measuring automatically correct

For the first time all instrument functions of a Dumas 

analyser are digitally controlled and monitored.

8

---

rapid N cube sets new bench marks

For the first time all instrument functions of a Dumas ana-

lyser are digitally controlled and monitored. This results in 

completely new possibilities of automatic operation, opti-

misation as well as remote control and diagnosis over the 

internet.

The basis for this is the use of the new micro processor gen-

eration with 24-bit signal processing as well as electronic 

sensors for gas flows and pressures.

The complete combustion process is monitored and con-

trolled by the system. The operator just has to select the 

sample type from the methods library.  All instrument pa-

rameters are then set. Oxygen dosing is controlled via a dig-

ital controller with feedback control based on the detector. 

This assures complete combustion with the minimal amount 

of oxygen consumption. The time of analysis is optimised by 

the system automatically. This results in the shortest time, 

but also allows for the complete combustion of even slow 

burning samples. Easy and correct operation by operators of 

different experience levels is achieved.

A commercial PC or laptop serves as control and evaluation 

unit which allows the fast change to the latest computer 

generation.

The design and operation of the Windows based software is 

a key component of our whole system. Our software is writ-

ten and developed in our own premises by our own person-

nel according to strict ISO 9001 requirements. The software 

allows for a continuous monitoring of real time conditions 

of the analyser in both numerical and graphical forms, easy 

and efficient input of run information with automated 

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 optimisation 

of parameters, monitoring of maintenance intervals and 

service messages, LIMS data transfer are all integrated into 

the system. Graphical leak checking with pictorial guides 

for each step is a new favorite feature of users. We also fea-

ture our unique browser based pictorial parts list, with drill 

down operation and exploded component diagrams.

Data safety and validity can be assured with the available 21 

CFR Part 11 compliant option

Main window operation surface instrument software

Leak test

9

---

* Element contents in [%] incl. standard deviation in [%]

Starch

Measurements 6

Weight 500 mg

Glutamic acid

Measurements 6

Weight 300 mg

Soya grist

Measurements 6

Weight 500 mg

EDTA

Measurements 6

Weight 250 mg

Flour

Measurements 9

Weight 500 mg

Inorganic fertilizer, solid

Measurements 6

Weight 150 mg

Malt

Measurements 9

Weight 500 mg

Soil

Measurements 6

Weight 1000 mg

Animal feed w. fish meal

Measurements 6

Weight 300 mg

Mixed provender

Measurements 4

Weight 300mg

Sulfanilic acid

Measurements 6

Weight 1 mg

Sunflower seeds

Measurements 6

Weight 150 mg

Flour

Measurements 6

Weight 30 mg

Milk powder

Measurements 6

Weight 1000 mg

Soil

Measurements 6

Weight 50 mg

Soya sauce

Measurements 6

Weight 500 mg

Alfalfa

Measurements 6

Weight 30 mg

Protein *

Nitrogen*

 0.214 ± 0.018

 9.517 ± 0.021

 46.05 ± 0.45

 9.589 ± 0.004

 12.237 ± 0.012

 21.104 ± 0.026

 9.246 ± 0.030

 0.0215 ± 0.0006

 32.985 ± 0.054

 19.85 ± 0.16

 18.53 ± 0.09

 22.13 ± 0.31

 0.1162 ± 0.0012

 3.335 ± 0.012

 0.0061 ± 0.0003

 9.08 ± 0.45

 0.283 ± 0.003

Sulfur*

10

---

Unlimited applications

Precise results within minutes

All organic and the majority of inorganic samples, liquid or 

solid, can be analysed. As a real macro analyser, the rapid 

N cube stands out due to the fact that the weight of organic 

samples may be up to the gram range without incomplete 

combustion and without forming tar or methane which 

may lead to false analysis results. This is possible due to the 

use of a lance injection of the oxygen directly at the place 

of combustion, a particularly effective catalytic post com-

bustion in a separate tube furnace, as well as the superior 

control of large combustion gas quantities. This is advanta-

geous e. g. for samples with a high fat content such as oil 

seeds or meat products.

The large sample amount allows the direct analysis also of 

inhomogeneous samples without extensive pre-treatment. 

Together with the highly sensitive TCD and the extreme sta-

bility of the gas flow, the high sample weight also allows 

low detection limits of below 20 ppm. This is important e.g. 

for samples with a very low nitrogen content such as ”lean 

soil“ or starch.

For samples with a high mineral content, like soil, the large 

ash crucible in the combustion tube is of advantage for the 

uninterrupted number of samples. The emptying of the ash 

crucible is easy and possible within a few minutes. Where 

required, the large measuring dynamics makes reliable an-

alytical results possible – also for samples of only a few mil-

ligrams. The efficient two-stage gas drying allows the serial 

analysis of aqueous sample material up to 1 ml volume. This 

applies also for difficult matrices or low concentrations like 

soy sauce, milk or beer. The correlation of the Dumas analy-

sis results with the Kjeldahl method is officially secured by 

a number of round robin tests and is the basis of national 

and international standards.

A great advantage is that a large number of applications 

only require one basic calibration which can be used for 

months or even years. Only an adjustment of the instru-

ment by 2–3 standard measurements to the instrument sta-

tus and the atmospheric pressure at the beginning of the 

measuring day is required. The repeated measurement of 

calibration standards or blanks within a day and/or within 

large measuring series is not necessary.

The rapid N cube can be easily and quickly modified to the 

fully automatic analysis of sulfur (option). Soil samples with 

a concentration of less than 100 ppm, plant material with 

0.1 % or even chemicals with up to 100 % sulfur can be de-

termined without problems.

For the simultaneous analysis of CNS in macro samples the 

additional instrument lines vario MAX cube and vario MACRO 

cube of the Elementar portfolio are available.

11

---

12

---

On behalf of your budget

rapid N cube is designed for the cost-

effective analysis of large sample series

Low purchase and installation costs

A complete operating system consists of the basic instru-

ment, PC/laptop and a 0.1 mg analytical balance. Approxi-

mately 1 m of standard width laboratory bench, power con-

nection (100 V–230 V) and two gases (CO

2

, O

2

) are required 

for the operation. A hand press for solid samples is included 

in the initial outfit. A special mechanical pellet press is also 

available. For liquid samples we recommend our economi-

cally priced press with cold weld sealing of the capsules. 

Provisions like air conditioning, special power lines, exhaust 

hoods, compressed air or cooling water are not required.

 

High long time stability

rapid N cube‘s design stands out for its minimum of valves, 

sealings and wires/tubes. The detector and the air condens-

er are almost maintenance-free. The instrument calibration 

can be used for months and years and the 3–tube furnace 

has a 10 years warranty. This results in a very long and trou-

ble-free operation time. 

Up to 120 samples can be analysed fully automatically also 

unattended and over night

Low costs per analysis

The reasons for the minimal operational costs are the ex-

tremely low oxygen consumption and the long operation 

times of the employed components.

The robust stainless steel combustion tube and the other 

consumables can be used for a large number of analyses. 

The analytically superior reduction of all operation gases by 

the patented use of tungsten instead of copper has further 

increased the capacity by a factor of 2-3.

Compared to the Kjeldahl method there are no additional 

costs for storage and disposal of chemicals and installations 

for acid digestion. There are also no time consuming man-

ual steps during operation.

Easy and safe operation 

The analyser does not require special skills for chemical 

analysis or the software. The automatic optimisation of 

the operating parameters by the special sensor technology 

and computing technology makes it possible to also attain 

correct analytical results with semi-skilled personnel. High 

safety standards of operation and the omission of toxic or 

caustic chemicals are also important.

Availability also in the future

As for all instruments of Elementar, the use of the rapid N 

cube is supported for more than 10 years. This applies to the 

availability of spare parts, the support by our worldwide 

service and the advice of our application specialists.

13

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Analysis method: 

Combustion method according to Dumas for nitrogen determination. 

 

Combustion of the sample, drying, cleaning and reduction of the combustion gases and  

 

detection of the nitrogen with a TCD

Operating modes: 

 N/protein as standard with TCD 

Optional S with IR detection

Digestion temperatures: 

 960°C for N determination 

1150°C for S determination 

Safety standards: 

CE-label, EN 61010-1, EMV low voltage directives 73/23/EEC

Analysis standards: 

 AOAC 990.03,AOAC 968.06, AOAC 993.13, AOAC 992.15, AOAC 992.23, ASBC, AACC, FGIS, AOCS, CGC 

(for fertilizer, meat, meat produce, cereals, oil seed, brewing grain, flour, animal feed), DIN/

EN/ISO 14891 (milk and milk products), DIN/ISO 13878 (soil), LUFA, MEBAK (brewing), ICC 167

Detection range*: 

 0 – 100% N  (or 500 mg N  absolute) 

 

0 – 100% S   (or    20 mg S  absolute)

Detection limit*: 

 < 20 ppm N  

< 10 ppm S

Standard deviation*: 

< 0.05 % abs.  (approx. 250 mg glutamic acid)

* depending on sample type, analysis mode and options

14

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Specifications rapid N cube

Calibration: 

Multi point calibration, regression linear to the 4

th

 order,  

 

stable over months.

Sample weight*: 

up to 1 g or 1 ml sample volume

Analysis time*: 

 approx. 4 min

Autosampler: 

 60 positions in a magazine as standard for samples up to approx. 1 g 

reloadable any time during operation 

or 120 positions to approx. 300 mg, optional

Gases: O

2

  99.995 % purity, approx. 0.4 l/analysis 

 CO

2

  99.995 % purity, approx. 4 l/analysis

Instrument control: 

 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, monitoring of the maintenance 

cycles, sleep-/wake up function, statistical evaluation and almost unlimited memory ca-

pacity for analysis data incl. graphics.  

Integration in data networks like LIMS and the possibility of remote control and diagnosis 

via the internet.  

In full compliance with 21 CFR Part 11 (option).

Electrical connections: 

100/110/200/230 V, 50/60 Hz, 1,8 kW

Dimensions: 

42 × 55 × 55 cm (B × T × H)

Weight: 

ca. 65 kg

* depending on sample type, analysis mode and options

15

---

Agrarian

Analysis

Chemical

Analysis

Fuel

Analysis

Water and  

Environmental  

Analysis

Consumables

Service

Isotope

Analysis

Elementar

Analysensysteme GmbH

Donaustraße 7

63452 Hanau (Germany)

Phone: 

[phone]

Fax: 

[phone]

Mail: [e-mail]

Web: www.elementar.de