Congener specific analysis of polychlorinated biphenyls (PCBs) in serum using GC/MSD

[Validation of an analytical methodology to determine polychlorinated biphenyls in samples from blood plasma]

INTRODUCTION

Polychlorinated biphenyls are among the five most toxic persistent contaminants for living organisms according to the Agency for Toxic Substances and Disease Registry (ATSDR).

OBJECTIVE

To standardize and validate an analytical method to determine and quantify polychlorinated biphenyl indicators in samples from blood plasma by means of gas chromatography-mass spectrometry.

MATERIALS AND METHODS

We fortified a plasma pool to do the matrix assays. Additionally, we used the NIST SRM® 1958 reference material for the veracity and intermediate accuracy assays.

RESULTS

Methodology recovery percentages ranged between 88.4 and 97.5%, and the bias was less than 20%. Detection and quantification limits were 0.04 μg/L and 0.10 μg/L, respectively, for all polychlorinated biphenyl indicators. The linearity represented by the determination coefficient (R2) varied between 0.9866 and 0.9886. Accuracy, expressed as relative standard deviation was less than 20% in all the linear work range (0.5-500 μg/L). Finally, we analyzed 115 samples from Colombian population in various zones of the country and we found 65 positive samples, from which two samples were above HBM-II (7.0 μg/L, 2XΣPCB 138, 153, 180), and two, above HBM-I (3.5 μg/L, 2XΣPCB 138, 153, 180).

CONCLUSION

The method we developed is accurate for PCB analysis in blood plasma samples and could be used for biological surveillance of these contaminants in the Colombian population.

Determination of polychlorinated biphenyls in serum using gas chromatography-mass spectrometry with negative chemical ionization for exposure estimation

A sensitive and selective method for the determination of 24 polychlorinated biphenyls (PCBs) by gas chromatography-mass spectrometry with negative chemical ionization (GC-MS-NCI) was applied for the recent needs of occupational exposure in waste incineration. The three most abundant ions were used in determining compounds with at least five chlorine atoms in the PCB molecule. Selecting ions Cl(35) and Cl(37) for di-, tri-, and tetrachlorinated PCBs resulted in reliable quantification of these compounds. The detection limits for the 24 individual compounds varied from 0.01 to 0.08 microg/l. The recovery of the method was 113+/-16%. Stability tests showed no degradation of the compounds studied during 6 weeks. The sum of 24 PCB compounds measured from the sera of workers in a disposal plant was 1.9-10.9 microg/l, and 0.3-3.0 microg/l for controls, respectively. The mean proportion of the low chlorinated PCB compounds (with four or less chlorine atoms) was 20% for workers in the disposal plant and 14% for the controls.

Analysis of pesticides and PCB congeners in serum by GC/MS with SPE sample cleanup

This paper describes a simple procedure for the quantitative analysis of 25 polychlorinated biphenyl congeners (PCB) in serum. They are PCB 70, 74, 77, 87, 99, 101, 118, 126, 128, 138, 151, 153, 156, 169, 170, 180, 183, 187, 191, 194, 205, 206, 208 and 209. In addition, 15 pesticides are analyzed in the same extract: aldrin, p,p'-DDE, p,p'-DDT, dieldrin, endrin, endosulfan I, heptachlor, hexachlorobenzene, alpha-hexachlorocyclohexane, beta-hexachlorocyclohexane, lindane, methoxychlor, mirex, pentachlorobenzene, and 1,2,3,4-tetrachlorobenzene. The procedure involved sample cleanup using a combination of C18 and NH(2) solid phase extraction cartridges. The instrumental technique was gas chromatography/mass spectrometry with both electron ionization and negative chemical ionization in the selected ion monitoring mode. Concentration of sub-ng/ml level was attainable with 2 ml of serum sample.