Routine-capable LC-GC system for on-line determination of mineral oil contaminations in food, feeding stuffs and packaging.
This system has been designed for the sensitive and fast detection of mineral oil contaminants in different matrices such as cosmetics, foodstuff, oils and fats, feeding stuff and packagings.
The method is thoroughly published and tested. In an article in FoodProductionDaily the method was described as the most efficient one: "According to EFSA, the most effective method to detect MOH levels in food is through pre-separation by high performance liquid chromatography (HPLC) online coupled to GC with flame ionisation detection (FID)." (Source).
Special advantages of the LC-GC-System MOSH/MOAH
- Simultaneous and fast determination of MOSH and MOAH
This system allows a determination of MOSH and MOAH in 30 minutes only.
- High level of automation
Through normal phase HPLC an automated sample preparation and pre-separation is realized. Thereby, MOSH and MOAH fractions are separated from one another and simultaneously from disturbing components like paraffin or wax esters. Standard sample preparation steps as solid phase extraction or manual purification are no longer required.
- Sensitive determination
- High level of reproducibility and accuracy
Great measuring accuracy, similar to a normal split/splitless injection; method validated.
- Routine-capable methods
A proper connection of LC and GC reduces solvent consumption and contamination of the GC system. Additionally, it strongly increases the stability of the system. The sample throughput is therefore increased and facilitated by the control through the user-friendly CHRONOS software.
- GCxGC-Functionality for better determination of MOSH, MOAH and POSH
Two GC columns with different polarities are applied. An upgrade for the CHRONECT LC-GC Interface is necessary, but can be added easily.
- NEW: Automated epoxidation as add-on for the LC-GC MOSH/MOAH application
A solvent change is no longer required due to the modification of the reaction conditions for epoxidation. Additionally, a better recovery of internal standards is given. Epoxidation can be automated within the LC-GC application system and can be done during the runtime of other samples. Another option is the Epoxidation Workbench consisting of a PAL3 RTC/RSI by CTC Analytics. Thus, a high number of samples can be processed offline.
Technical setup of the device
The MOSH/MOAH-System consists of a binary HPLC system, a GC including two FIDs, an evaluation software, CHRONECT Robotic constisting of a PAL3 Autosampler by CTC Analytics and the software platform CHRONOS by Axel Semrau. The key to success are following technical details:
- Intelligent valve connection: Holds back the MOSH fraction eluted first without losses until the MOAH fraction enters the GC. Then, sample injection to the GC is performed.
- Large-volume injection: The injection into the GC is performed by independent large-volume injection systems. Injection volumes up to 450 µL can be processed smoothly.
- 2-Channel-GC: Two parallel and orthogonal chromatographic separations with subsequent FID detections are performed. Consequently, the results concerning MOSH and MOAH contents in a sample are readily available after 30 minutes only.
- CHRONOS software: The software platform CHRONOS controls sampling, LC and GC including the valve connection and thus constitutes a completely automated control of the method and sample preparation.
This requirements for such a system were developed in close collaboration with end users. Using the CHRONECT LC-GC interface by Axel Semrau the usage of various gas chromatographs is possible. Concerning HPLC, the system may be configured either with a HPLC of KNAUER, Agilent or Shimadzu.