The determination of trace metals in soil is used to assess pollution levels or to monitor the extent and effectiveness of ecological restoration. The measured elements can be diverse, but typically include toxic elements such asAsTheSeTheTlandPbThese elements can exist in natural soil or deposit in soil, but their own concentrations are generally low. Pollutants or improper waste discharge from industrial production often cause an increase in their concentration. Determining the level of pollution in a certain area or monitoring the process of ecological restoration may require multiple measurements, and efficiency can be improved by synchronously measuring multiple elements within the required low concentration range. This article introduces the use of graphite furnace atomic absorption and Zeeman background correction for synchronous measurement and analysis of four elements in various sediments and soils.

experiment Perkin ElmerSIMAA ™ 6000Atomic absorption system(AAS) Used for all measurements.SIMAAUsing a step grating spectrometer, the light is directed towards a solid-state diode array detector, which can simultaneously detect up to six elements. Horizontal heating graphite furnace and Zeeman effect background correction are important components of the constant temperature platform furnace concept and help eliminate interference as a whole. According to the table 1 As shownAsTheSeTheTlandPbThis atomic absorption system has been set up.

table 2 The graphite furnace program for all elements is displayed in. The sample being tested is fromHigh Purity Standards, Charleston, SCVerified samples of estuarine sediment, river sediment, and soil. The above materials are provided in2%Prepared from nitric acid, It can provide various pollution levels and natural elemental composition levels. The method used for analysis follows the United StatesEPA Method 200.9The process described in the method.(1)

This method usesSTPFConcept, applicable to 16 This element is highly suitable for use with synchronous atomic absorption systems. During the drying and high-temperature decomposition pretreatment stages, this method uses another gas（5%Hydrogen and95%A mixture of argon gas is used to ensure the presence of its own components in the sampleClOr added during the digestion processCleliminate. A step of blowing the graphite furnace has been added to the graphite furnace program to remove residual hydrogen gas before the atomization step.

Results and Discussion The calibration curve is displayed in the figure 1 In the middle. These curves are linear curves, approximately150 µg/LIf permitted by the regulatory agency, it can also be smoothly used for higher concentrations. Observation of calibration curves within the complete concentration range andQCInspection can ensure that data meets quality objectives. table 3 The expected instrument detection limit is displayed in the middle, which is achieved by measuring the low concentration standard sample 7 Multiply the standard deviation of repeated measurements by 3 Calculated. This detection limit is affected by instrument performance and may vary with changes introduced during the digestion process. The table also displays the detection limit of the solution introduced into the instrument, as well as the typical digestion method used 1 g Dissolve the soil and dilute it to a volume of 100 mL）The detection limit that can be detected in soil.

River sediment after adding standardsAThe peak is displayed in the figure 2 In the middle. Please note that the background signal is high, but it can be easily compensated by Zeeman background correction. Compare the results obtained here with the table4-8Compare the validation values in. The dilution factor varies to some extent depending on the degree of pollution, and is usually used for moderate pollution0-2xThe dilution factor. In the pollution process When the degree is high, this software can be instructed to automatically execute Additional dilution to provide absorption values within this calibration range. The spiked substance in the sample is25 µg/LIn some cases, the recovery rate was observed by instrument dilution.

Conclusion In soil degradation productsAsTheSeTheTlandPbThe synchronous measurement has been proven to be a feasible analytical method. The detection limits of these four elements are excellent, and even if the volatility is different, there is almost no need to make any adjustments when combining elements. Horizontal heating furnace, Zeeman background correction, and other components provided in the systemSTPFThe combination of components can reduce interference and lower the requirement for adding standard samples in this method.