Arntraut Götsch,a, Maria Averina,a,b, Jan Brox,a and Sandra Huber,a
a Department of Laboratory Medicine, University Hospital of North Norway, Hansine Hansens veg 67, 9019 Tromsø,
Norway
b Tromsø Endocrine Research Group, Institute of Clinical Medicine, UiT-The Arctic University of Norway, Hansine
Hansens veg 18, 9019 Tromsø, Norway
Email: Arntraut.Goetsch@unn.no
Organochlorine pesticides are a diverse group of compounds, e.g. Chlordanes, Hexachlorocyclohexanes, Dichloro-diphenyl-trichloroethane and its metabolites etc. Most of them are regulated in the Stockholm Convention as legacy POPs (2). In compliance with the Stockholm Convention, these POPs still need to be monitored to enable national authorities to determine whether further action, beyond monitoring, is necessary. At the Environmental Pollution Laboratory at the University Hospital of Northern Norway, organochlorine pesticides are analysed in human research samples, often from population studies investigating associations between environmental pollutants and adverse health effects.
The sample preparation and original instrumental analysis method was established and validated previously (1). In brief, 150 µL of sample (human serum or plasma) are extracted using reversed phase extraction on a 96-well SPE plate (Oasis HLB, 60 mg, Waters, Milford, USA), followed by a clean-up using normal phase methodology on custom made Florisil colums (Sep-Pak, 100 mg, 1 cc, Waters, Milford, USA), and finally measured on a Waters APGC vs 1 with a modified Agilent 7890a GC coupled to a Xevo TQ-S tandem-quadrupole mass spectrometer system. This method has been transferred to a newer generation Waters MS-system, a Waters APGC vs 2 with a modified Agilent 7890b GC coupled to a Xevo TQ-XS tandem-quadrupole MS.
For performance comparison of the two systems, eight standard reference material samples (four samples NIST 1957, non-fortified and four samples NIST 1958, fortified human serum), 12 external assessment samples and 30 serum samples from the general population (all from Tromsø, age 14-91 years, 15 male and 15 female individuals) were prepared according to our standard procedure on the liquid handler and measured for 23 different organochlorine pesticide compounds on both instruments.
For the quantification the internal standard method was applied with a calibration containing 11 calibration points at the following concentrations:0,005 pg/µL, 0,01 pg/µL, 0,025 pg/µL, 0,05 pg/µL, 0,1 pg/µL, 0,25 pg/µL, 0,5 pg/µL, 1 pg/µL, 2,5 pg/µL, 5 pg/µL, 10 pg/µL. The software used was Masslynx and Targetlynx version 5.2.
Linearity was investigated and was slightly better on the newer generation system, whereas sensitivity was much better on the newer system. On the Xevo TQ-S instrument several compounds could not be detected at the lowest calibration points, whereas they were detected on the Xevo TQ-XS system.
The overall impression is that the newer generation system has clear advantages with better sensitivity and higher detection frequency in real samples with increased number of detected analytes.
References
1 Huber, S.; Averina, M.; Brox, J. Automated sample preparation and GC-API-MS/MS as a powerful tool for analysis of legacy POPs in human serum and plasma. Anal. Methods 2020, 12, 912–929.
2 http://www.pops.int/TheConvention/ThePOPs/tabid/673/Default.aspx, accessed at the 12.11.2025