Fast Determination of PAH and PCB in one Run

Environmental contract labs face a hard price pressure. To overcome this pressure, a trend into the direction of Multi/Multi Methods can be observed. If possible, more than one parameter group shall be determined and measured with one instrument without changing hardware. This implements a specific request for the separation power of the column used and the detection power of the installed instrument base.

The appearance of PAH and/or PCB contamination is a suitable indicator for industrial contamination of different matrices like Water, Sludge, Soil and Dust. Both parameters are among the most measured compound classes in environmental analysis in Europe.

To optimize this measurement and to improve their new TQ-8030 GC/Q³ system, Shimadzu Germany recently showed an application which determines both compound classes in one run within 11 minutes by using Hydrogen as carrier gas and a Pseudo-MRM technique to increase PAH sensitivity.

German and International Standards are requesting some frame conditions for the determination of these compounds.

The German Dump Regulation names ISO 18287 with GC/MS detection as method of choice. The alternative EN 15308 names GC/ECD detection and GC/MS detection as suitable, so the Q³ approach of the Shimadzu Scientists is according to the existing norms. The German sewage sludge ordinance asks for no interference between PCB 101 and o,p’-DDE or alpha-Endosulphane and between PCB 138 and p,p’-DDT.  Most challenging, a good separation between PCB 28 and PCB 31 is required. The developed application used DIN 38 414–20 as base for sample preparation.

A lot of instrument companies rely on Restek Products, when it really matters. So, in this case, a Restek Rxi-XLB column (l= 20 m; ID = 0.18 mm; dF= 0.18 µm) was chosen to run the separation.

The original paper shows the good separation between the two PCBs 28 and 31 (R>0.94), as shown in Picture 1, and no Interferences between the named PCB and PAH compounds, although measured in one run.

Picture 1: Separation between PCB 28 and 31	Picture 2: Chromatogram of a PCB/PAH mixture (all 5 ng/µl)

 

More details about the method, the usage of Hydrogen as carrier gas and how to optimize a Q³ by setting Pseudo MRMs for PAHs can be looked up in the original paper (in German), published in Nachrichten aus der Chemie| 62 | Mai 2014 |