Solid Waste-Determination of Dioxins-Isotope Dilution High Resolution-Gas Chromatography-High Resolution Mass Spectrometry (3)

7.

(1) Qualitative

Two monitoring ions of dioxins congeners exist at the same time within the specified retention time window, and their ion abundance ratio is consistent with the theoretical ion abundance ratio listed in Table 4 of HJ77.

In addition to meeting the above requirements, the following conditions must be met for 2,3,7,8-chlorodioxin compounds: the retention time of the chromatographic peak should be consistent with the standard solution (within ±3s), and the relative retention time of the internal standard It is also consistent with the standard solution (within ±0.

(2) Quantitative

1.

The internal standard method was used to calculate the absolute quantity Q(ng) of the dioxins detected in the analysis samples, and the absolute quantity of 2,3,7,8-chlorodioxin compounds was calculated according to formula (5)

In the formula, A——the sum of the peak areas of the monitored ions of the compounds to be tested in the chromatogram;

A _{es ——the} sum of the peak areas of the monitored ions extracted from the internal standard;

Q _{es ——the} amount of added internal standard extracted, ng;

RRF _es ——The relative corresponding factor of the test compound relative to the extracted internal standard

2.

Use formula (6) to calculate the content w'(ng/kg) of the test compound in the sample, and the result is rounded to 2 significant figures

In the formula, Q—the mass of the compound to be tested in the analysis sample, ng;

m—the mass of the sample, kg;

wH ₂ O—moisture content, %

3.

According to the ratio of the peak area of ​​the extracted internal standard to the peak area of ​​the injected internal standard and the mean value of the corresponding relative corresponding factor (RRF _rs ), the recovery rate R (%) of the extracted internal standard is calculated according to formula (7) and the recovery rate of the extracted internal standard is determined Within the range specified in Table 5 of HJ77.

In the formula, A _es -the sum of the peak areas of the monitored ions extracted from the internal standard;

A _rs —the sum of the peak areas of the monitored ions of the injected internal standard;

Q _rs —addition amount of internal standard for injection, ng;

RRF _rs —The relative response factor of the extracted internal standard relative to the injected internal standard;

Q _es ——the added amount of the internal standard extracted, ng

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