Question

A researcher was attempting to quantify the amount of dichlorodiphenyltrichloroethane (DDT) in spinach using gas chromatography mass spectrometry (GCMS). First attempts using external calibration proved difficult, as reproducibility and external standard agreement were poor. To overcome these problems, the researcher used the internal standard calibration method with chloroform as the internal standard. To begin, the researcher analyzed a sample containing 6.32 mg/L DDT standard and 3.64 mg/L chloroform as the internal standard, which produced peak areas of 4943 and 9273 for the DDT and chloroform, respectively. Determine the response factor (F). F = After establishing the response factor of the instrument, the researcher collected 10.14 g of spinach, homogenized the sample, and extracted the DDT using an established method, producing a 3.52 mL solution containing an unknown amount of extracted DDT. The researcher then prepared a sample for analysis that contained 0.500 mL of the unknown DDT solution and 1.75 mL of 11.25 mg/L chloroform, which was diluted to a final volume of 25.00 mL. The sample was analyzed using GCMS, producing peak areas of 7659 and 14803 for the DDT and chloroform, respectively. Calculate the amount of DDT in the spinach sample. Express the final answer as milligrams of DDT per gram of spinach. amount of DDT: mg DDT /g spinach

          A researcher was attempting to quantify the amount of dichlorodiphenyltrichloroethane (DDT) in spinach using gas chromatography mass spectrometry (GCMS). First attempts using external calibration proved difficult, as reproducibility and external standard agreement were poor. To overcome these problems, the researcher used the internal standard calibration method with chloroform as the internal standard.
To begin, the researcher analyzed a sample containing 6.32 mg/L DDT standard and 3.64 mg/L chloroform as the internal standard, which produced peak areas of 4943 and 9273 for the DDT and chloroform, respectively.
Determine the response factor (F).
F =
After establishing the response factor of the instrument, the researcher collected 10.14 g of spinach, homogenized the sample, and extracted the DDT using an established method, producing a 3.52 mL solution containing an unknown amount of extracted DDT. The researcher then prepared a sample for analysis that contained 0.500 mL of the unknown DDT solution and 1.75 mL of 11.25 mg/L chloroform, which was diluted to a final volume of 25.00 mL. The sample was analyzed using GCMS, producing peak areas of 7659 and 14803 for the DDT and chloroform, respectively.
Calculate the amount of DDT in the spinach sample. Express the final answer as milligrams of DDT per gram of spinach.
amount of DDT: mg DDT /g spinach

A researcher was attempting to quantify the amount of dichlorodiphenyltrichloroethane (DDT) in spinach using gas chromatography mass spectrometry (GCMS). First attempts using external calibration proved difficult, as reproducibility and external standard agreement were poor. To overcome these problems, the researcher used the internal standard calibration method with chloroform as the internal standard.
To begin, the researcher analyzed a sample containing 6.32 mg/L DDT standard and 3.64 mg/L chloroform as the internal standard, which produced peak areas of 4943 and 9273 for the DDT and chloroform, respectively.
Determine the response factor (F).
F =
After establishing the response factor of the instrument, the researcher collected 10.14 g of spinach, homogenized the sample, and extracted the DDT using an established method, producing a 3.52 mL solution containing an unknown amount of extracted DDT. The researcher then prepared a sample for analysis that contained 0.500 mL of the unknown DDT solution and 1.75 mL of 11.25 mg/L chloroform, which was diluted to a final volume of 25.00 mL. The sample was analyzed using GCMS, producing peak areas of 7659 and 14803 for the DDT and chloroform, respectively.
Calculate the amount of DDT in the spinach sample. Express the final answer as milligrams of DDT per gram of spinach.
amount of DDT: mg DDT /g spinach

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