New: CHRONECT Workstation PAH and imPAHct

Automated analysis of PAH in foodstuff by LC-LC-GC-MS/MS coupling and the imPAHct method


The CHRONECT Workstation PAH and the newly developed imPAHct method (innovative multidimensional PAH clean-up technology) by Axel Semrau® provide a high level of automation.


Polycyclic aromatic hydrocarbons (PAHs) are formed during partial combustion and pyrolysis processes. They enter the environment through fumes, bound to dust particles or mineral oil residues. PAHs contaminate foodstuff either from the environment (e.g. dust particles on broad-leaf vegetables) or by roasting and smoking processes.


Laboratories analyze PAHs regularly. The reason for this is the partly very high carcinogenicity of the substance group and their broad distribution. European guidelines set limiting values which vary depending on the foodstuff. For the marker substance benzo[a]pyrene the value lies between 1-6 μg/kg while the total limit value for the PAH4 (this term summarizes benzo[a]pyrene, benzo[a]anthracene, chrysene and benzo[b]fluoranthene) is 1-35 μg/kg. The analysis of polycyclic aromatic hydrocarbons (PAH) is a great analytical challenge, due to the variety of food matrices and the detection limits demanded by the European Food Safety Authority (EFSA).


Due to the required sensitivity and complex matrices, PAH determination is a great challenge for analytics. As an analytical method either HPLC with fluorescence detection or GC-MS are used. Sample preparation is often extensive and time-consuming. Conventional analysis methods are using HPLC with fluorescence detection or GC-MS. In both cases, the sample preparation is often extremely extensive and complex. Recent requirements to laboratories include a  reduction in sample handling time (Turn-Around-Time) and an increase in the sample throughput. Still, no losses within the analytical parameters, e. g. sensitivity, precision and accuracy are desired. Consequently, highly automated analytical procedures are necessary.


The CHRONECT LC-GC technology by Axel Semrau® has been established for many years in the routine analysis of foodstuff. It forms the ideal base for the solution presented here. The analytics of PAHs is done by a LC-LC-GC-MS/MS system and with the imPAHct method. To measure PAHs, a simple yet fast extraction of the sample is performed. The extract is quickly manually treated and then transferred to the CHRONECT Workstation PAH. Here, the extract is purified by a two-step LC separation (LC-LC Clean-Up)  and subsequently analyzed via GC-MS. Edible oils may be measured straightforwardly.


Applying this intelligent matrix management, it is possible to determine the PAHs which are prescribed by EFSA fully automated. Depending on the detector, detection limits are reached which are even lower than the required European values for infant formula by a factor of 100.


The LC-GC solutions by Axel Semrau® are pre-installed and tested in our application laboratory. They are delivered in a ready-for-use condition. The installation includes a Site Acceptance Test as well as a briefing which enables the user to start working with our solution immediately. This ensures the fastest possible start of the routine measuring operation.


Benefits of the CHRONECT Workstation PAH and the imPAHct method

  • LOD 1/100 of the limit value for infant formula (example substance benzo[a]pyrene)
  • LOD for all EFSA PAH between 0.01 -
    0.02 μg/kg with Bruker EVOQ GC-TQ
  • LOQ for all EFSA PAH < 0.06 μg/kg with Bruker EVOQ GC-TQ
  • repeatability < 10 % for the entire method
  • analysis duration: 45 min
  • no consumables necessary due to LC-LC Clean-Up
  • longer maintenance intervals due to Clean-Up technology
  • applicable to cosmetics and all foodstuff
  • high sample throughput
  • high degree of automation
  • investment safety
  • universally applicable to all foodstuff
  • short training period due to the prepared method

System components

  • CHRONECT Robotic consisting of:
    CTC PAL3 with a 85 cm axis
    and
    Software CHRONOS
  • Agilent 1260 Infinity II HPLC pump
    with UV detector and degasser
  • Bruker EVOQ GC-TQ
  • CHRONECT LC-GC Interface for LC-GC coupling
  • data system with control and evaluation software
  • accessories and consumables
  • Factory Acceptance Test
  • instruction and commissioning
  • Site Acceptance Test
  • training and support


LC-LC-GC-MS/MS measurement of cocoa butter which was doted to 0.04 μg/kg with PAH

LC-LC clean-up: first and second purification

Calibration curve for benzo[a]pyrene between 0.04 - 4 μg/kg