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ARACUS advanced Amino Acid Analyzer

Extended configuration of the ARACUS Classic


Dr. Sonja LöfflerState Forestry, Forestry Competence Centre Eberswalde, Germany
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"We have been determining the free amino acids in plant samples with the ARACUS amino acid analyzer since 2010. From the beginning, we were won over by the very good service provided by the team from membraPure. The high accuracy and reproducibility of the measurement results should be emphasized, which is an advantage for long-term monitoring studies. The system works reliably and the provision of ready-made solutions and standards means that the amino acid analyzer is extremely user-friendly. Due to the fully automatic and time-efficient operation of the device, the determination of the amino acids is also very suitable for numerically extensive sample series."
Hongkeun YooLG Chem, Korea
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"Recently, there has been an issue where retention time has been different when measuring the same standard, an equipment inspection is currently in progress. I am satisfied that the person in charge is solving the problem prompt."
Dr. Leslie WillisDayton Children´s Hospital, USA
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Excellent system. Software is manageable. Support is outstanding. We use the instrument in a clinical diagnostic laboratory and have found it to be very reliable, requiring little maintenance. We do have some issues getting consumables into the US."
Inga MewisHumboldt-Universität zu Berlin, Germany
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"The ARACUS system is great for easy analysis of amino acids in different tissues (physiological analysis). The machine is running very reliably. Using the physiological standards provided, easy identification and quantification can be performed. It is very important to perform a deproteinization step using the sample preparation kit from membraPure before analysis and filtration of samples through 0.22 µm filter. Great separation of amino acids in extracts can be obtained from different freeze dried material of plants, insects, and fish. The analysis of amino acids with ARACUS is easier and more convenient compared to the ninhydrin pre-column derivatization. Furthermore, though we haven’t had any problems, the service has been very helpful, and we found the company very understanding of the needs of the scientific community."
Hyeran ChoAjinomoto Genexine, Korea
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"It's so convenient and user-friendly. I really like to use this equipment. The results fit well with our recipes."
Mohammed Wedyan The Hashemite University
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"The amino acid analyzer ARACUS has been in operation since 2016 and fits perfectly with our needs. We analyze free amino acids in water. The analyzes are carried out routinely and fully automatically. The results are reproducible. We are supported by MembraPure experts in evaluating the methods."


Most efficient analysis results with two pumps

  • The ARACUS „advanced“ is an extended configuration of the ARACUS „classic“ by an additional second pump drive.
  • The system allows the continous analysis of 96 samples in a cooled autosampler.
  • The upgraded pump configurations allows the independent operation of two fluidic lines (eluent side and reactive side).
  • The use of two pump drives results in an improved signal-to-noise ratio of the chromatogram.
  • The freely adjustable parameters between the eluent and the reagent pump drives also provide the possibility of using the reagent OPA (o-phthalaldehyde) for detection of primary amines with a fluorescence detector.
  • The addition of ninhydrin provides a quantitative analysis statement
  • washing routine of the injection valve and syringe pump avoids cross contaminations.

Main technical specifications of the system​


The chart shows the structure of the advanced setup:

  • The upgraded pump configurations allows the independent
    operation of two fluidic lines
    (eluent side and reactive side).
  • The use of two pump drives results in an improved signal-to-noise
    of the chromatogram.
  • The system is equipped with an autosampler with 100 µL loop.
Flowchart: ARACUS advanced
Options: Manual injection Aracus

Manual injection port

Upon request each system can be supplied as manual configuration.

Options: Purge valve Aracus

Prime and purge valves

High pressure side prime and purge valves in eluent and reagent flow.

Options: IQQ Documents Aquinity P10

IQ/OQ/PQ documents

Validation documents IQ/OQ and PQ for ARACUS.

Options: Detector Aracus

Fluorescence detector

For sensitive fluorescence detection of 1° amines with o-phatalaldehyde (OPA) we are providing the suitable fluorescence detector.

Options: Inert gas Aracus

Inert gas

It supplies the main unit and eluent box with a protective gas atmosphere by reducing the presence of atmospheric oxygen to enhance the signal to noise ratio.

Options: Levelsensor Aracus

Level control

Active control of fluid volume by weight cell of each bottle. (only available with software aminoPeak).

Options: IVD Kit Aracus

InVitro diagnostic kit IVDD 98/79 EC

IVD kit for the qualitative and quantitative determination of amino acids in physiological fluids like human blood and urine for medical diagnostics in combination with the ARACUS IVD advanced.

Options: Software Aracus

Software 21 CFR Part 11 compliance

Manual and automatic peak integration with integrated IQ/OQ procedure for software (only available with software Clarity).

Technical Specifications
methodpost column derivatization with Ninhydrin or OPA
autosampler2 racks, each of them with space for 48 vials, sample cooling dosage in 3 different injection modes: full loop (100 μL), partial loop (5 - 50 μL), microliter pickup (1 - 35 μL)
columnstainless steel, cation exchange resin reproducibility of retention time < 1 % RSD, reproducibility of peak area < 3.0 % RSD
column oven20 - 100 °C, accuracy 0.1 %
reactor temperature20 - 140 °C
spectroscopic detectionmeasuring range: high, low LED photometers (440 nm + 570 nm), 8 years warranty, flow cell: 10 μL volume, 3 years warranty
detection limit< 40 pmol / 20 µL with Ninhydrin, < 4 pmol / 20 µL with OPA
quantification limit> 100 pmol / 20 µL with Ninhydrin, > 10 pmol / 20 µL with OPA
pump systemdual pump reproducibility of low rate: 0.1 % RSD at 100 μL/min, max. pressure: 400 bar | flow rate: 0.01 - 10.00 mL/min
maximum operating pressure120 bar
ready to use kitskits including eluents, reagent and additional dilution buffer, ammonia adsorber and separation columns for 500 - 1000 runs
columns & eluentsCompatible with all columns, operating with all eluents based on different ionic strength (Li, Na, K)
control software & data aquisitionClarity (21 CFR part 11 compliant) or AminoPeak
dimensions, weight, power1000 x 680 x 360 mm*, 60 kg, 110 - 230 V
*800 mm with opened main unit


Chromatographic separation of the amino acids is performed by ion-exchange chromatography, followed by post-column derivatization with ninhydrin (Stein & Moore) and photometric determination by LED. Alternatively, derivatization with o-phthaldialdehyde and detection of the concentration with a fluorescence detector can be performed.

All applications dealing with amino acid analysis can be covered. These include the analysis of food and feed, the analysis of clinical samples such as blood plasma, urine or spinal fluid as well as research questions.

The ARACUS is the only system in the series that is a 2-pump system. One pump independently regulates the flow of reagents and one pump regulates the flow of eluents. The use of a 2-pump system also provides a better baseline. In addition, post-column derivatization with o-phthaldialdehyde and a fluorescence detector allows the customer to detect amino acids and biogenic amines at a lower concentration.

The autosampler includes 2x 48 sample vials, which have a capacity of 1.5 mL. For small sample volumes, inlets can be used for the sample vials to ensure proper sample collection.

If the system is operated with the Clarity software, this option is possible. Contact us.

The system has an alarm system with three different levels. At "yellow" the user is informed about a situation that is not critical, at "orange" a controlled shutdown of the system is performed and at "red" the system is secured against serious damage by emergency shutdown.

The system works with a pre-sequence, the analysis sequence and a post-sequence. When the measurement sequence is completed, the system goes into standby and runs a circulation to keep the system in an equilibrated state to be able to start a new measurement again as quickly as possible.

You can determine the heating profile of the column oven, the temperature of the reactor, the flow of the eluents, and the selection of the eluents yourself. Optimized programs are delivered with the system as standard.

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Analysis of the amino acid composition of cell culture media
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