Determination of Polychlorinated Biphenyls in Soil

This article refers to "HJ 743-2015 Determination of Polychlorinated Biphenyls in Soil and Sediment by Gas Chromatography/Mass Spectrometry", and establishes a method for detecting polychlorinated biphenyls in sediment using the Fotector Plus high-throughput fully automatic solid phase extraction instrument combined with gas chromatography/mass spectrometry. In the system of acetone-n-hexane (1+1), after extraction with the HPFE high-throughput pressurized fluid extraction instrument, it is concentrated to 1mL with the MPE series vacuum parallel concentrator, and the Fotector Plus high-throughput fully automatic solid phase extraction instrument is used for purification, automatically completing the steps of SPE column activation, sample loading, rinsing, and collection. The collected liquid is then concentrated, solvent converted, and volume adjusted with the Auto EVA 80 high-throughput fully automatic parallel concentrator, and then detected with gas chromatography-mass spectrometry.

Sample Pretreatment

>Extraction

Weigh 10g of sieved environmental soil sample, add an appropriate amount of diatomaceous earth and mix evenly, then fill into a 34mL extraction pool. The same method is used to fill six extraction pools. The six samples that have been extracted at the same time are placed in the HPFE, and the extraction is carried out twice in a cycle. The extraction liquid is collected and the water is removed with anhydrous sodium sulfate.

HPFE Series High Throughput Pressurized Fluid Extractor

>Pre-concentration

After the sample is concentrated to 1mL, add 10mL of hexane and continue to concentrate to 1mL.

MPE Series High Throughput Vacuum Parallel Concentrator 

>Purification

Solid Phase Extraction Column:

Florisil Column (RayCure, 1g/6mL)

Activation:

Hexane

Cleaning Sample Bottle:

Acetone: Hexane (1:9)

Rinsing:

Acetone: Hexane (1:9)

Fotector Plus High Throughput Fully Automatic Solid Phase Extraction Instrument

>Concentration

Use hexane for nitrogen blowing and dissolution for GC-MS detection.

Auto EVA 80 High Throughput Fully Automatic Parallel Concentrator

Gas Chromatography-Mass Spectrometry (GC-MS) Conditions

Results and Discussion

After the sample was pretreated and extracted, it was purified with Fotector Plus. The overall recovery rate was calculated using the matrix spike curve. The overall average recovery rate was between 77.67% and 106.01%, and the RSD was less than 7.2 (n=4), which meets the standard requirements for recovery rate. It complies with the allowable difference requirements of "HJ 743-2015 Determination of Polychlorinated Biphenyls in Soil and Sediment by Gas Chromatography/Mass Spectrometry". The recovery rate and RSD are shown in Table-1:

Summary

This experiment successfully replicated the “HJ 743-2015 Determination of Polychlorinated Biphenyls in Soil and Sediment by Gas Chromatography/Mass Spectrometry” using the Raykol Fotector Plus high-throughput fully automatic solid phase extraction instrument. The recovery rate and RSD met the allowable deviation requirements of HJ 743-2015, and complied with the quality control requirements for analysis results in HJ 743-2015.

The Raykol HPFE high-throughput pressurized fluid extraction instrument, as an essential device for soil extraction, can extract six samples simultaneously in 30 minutes. With a working time of 8 hours, the daily processing capacity can reach 96 samples. The instrument is easy to operate, controlled by a touch screen, and can be operated immediately by new laboratory personnel. The instrument has four solvents, which can be extracted in different proportions without manual preparation.

The Raykol MPE series high-throughput vacuum parallel concentrator can concentrate 20 large-volume samples or 48 small-volume samples in 30 minutes, greatly improving the efficiency of sample pretreatment. The Fotector Plus high-throughput fully automatic solid phase extraction instrument can simultaneously process 6 samples and automatically continuously process 60 samples. All basic commands from activation, sampling, rinsing to elution are fully automated, greatly improving the accuracy and reliability of the instrument and ensuring the recovery rate.

The Raykol Auto EVA 80 high-throughput fully automatic parallel concentrator’s nitrogen blowing needle can automatically descend with the liquid surface, maintaining the optimal concentration distance throughout the process, and can quickly and parallelly complete the concentration. The fully automatic process truly liberates the labor of laboratory personnel.