{"id":3989,"date":"2025-10-10T16:25:51","date_gmt":"2025-10-10T08:25:51","guid":{"rendered":"https:\/\/www.pgeneral.com\/?p=3989"},"modified":"2025-10-10T16:25:51","modified_gmt":"2025-10-10T08:25:51","slug":"determination-of-lead-in-graphite-powder-graphite-furnace-atomic-absorption-spectrometry","status":"publish","type":"post","link":"https:\/\/www.pgeneral.com\/it\/applications\/determination-of-lead-in-graphite-powder-graphite-furnace-atomic-absorption-spectrometry\/","title":{"rendered":"Determinazione del piombo in polvere di grafite (spettrometria di assorbimento atomico forno di grafite)"},"content":{"rendered":"

1. Method Overview<\/h2>\n
After the sample is digested by microwave, it is injected into the graphite furnace of an atomic absorption spectrophotometer. After electrothermal atomization, it absorbs the resonance line at 283.3 nm. Within a certain concentration range, the absorbance is proportional to the lead content. Quantitative determination is performed by comparison with a standard series.<\/div>\n
\n

2. Instruments and Reagents<\/h2>\n

2.1 Instruments and Equipment<\/h3>\n

2.1.1 Testing Instruments<\/h4>\n
\n
\n\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nQuantity<\/th>\nTechnical Requirements<\/th>\nAccessories<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nGraphite Furnace Atomic Absorption Spectrophotometer<\/td>\n1 set<\/td>\n–<\/td>\nLead Hollow Cathode Lamp<\/td>\n<\/tr>\n
2<\/td>\nArgon Gas<\/td>\n1 cylinder<\/td>\nPurity \u2265 99.99%<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nCooling Circulating Water System<\/td>\n1 set<\/td>\nRated water pump flow rate: 3.5 L\/min<\/td>\n–<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.1.2 Sample Pretreatment Equipment<\/h4>\n
\n
\n\n\n\n\n\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nQuantity<\/th>\nTechnical Requirements<\/th>\nAccessories<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nMicrowave Digestion System<\/td>\n1 set<\/td>\nEquipped with platinum resistance and infrared temperature measurement; pressure measurement accuracy: \u00b10.1 \u2103<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\nTemperature-Controlled Hot Plate<\/td>\n1 set<\/td>\nRated temperature range: Room temperature ~ 300 \u2103<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nElectronic Balance<\/td>\n1 set<\/td>\nSensitivity: 0.1 mg<\/td>\n–<\/td>\n<\/tr>\n
4<\/td>\nUltrapure Water System<\/td>\n1 set<\/td>\n–<\/td>\n–<\/td>\n<\/tr>\n
5<\/td>\nMicropipette<\/td>\n1 each<\/td>\nRanges: 20 \u03bcL ~ 200 \u03bcL, 100 \u03bcL ~ 1000 \u03bcL<\/td>\n–<\/td>\n<\/tr>\n
6<\/td>\nVolumetric Flask<\/td>\nSeveral<\/td>\nVolume: 100 mL<\/td>\n–<\/td>\n<\/tr>\n
7<\/td>\nTest Tube<\/td>\nSeveral<\/td>\nVolume: 25 mL<\/td>\n–<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.2 Reagents<\/h3>\n

2.2.1 Raw Reagents<\/h4>\n
\n
\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nTechnical Requirements<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nHydrochloric Acid<\/td>\nGuaranteed Reagent (GR)<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\nNitric Acid<\/td>\nMOS Grade<\/td>\n–<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.2.2 Prepared Reagents<\/h4>\n
\n
\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nPreparation Method<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\n(1+99) Nitric Acid Solution<\/td>\nMeasure 10 mL of nitric acid, slowly add it to 990 mL of water, and mix well.<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\n(5+95) Nitric Acid Solution<\/td>\nMeasure 5 mL of nitric acid, slowly add it to 95 mL of water, and mix well.<\/td>\n–<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.3 Reference Standards<\/h3>\n

2.3.1 Stock Solution<\/h4>\n
\n
\n\n\n\n\n\n
Serial No.<\/th>\nNo.<\/th>\nName<\/th>\nTechnical Requirements<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nGSB G 62071-90<\/td>\nLead Single-Element Standard Solution<\/td>\nConcentration: 1000 \u03bcg\/mL<\/td>\nProvided by National Analysis and Testing Center for Nonferrous Metals and Electronic Materials<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

3. Operational Procedures<\/h2>\n

3.1 Sample Preparation<\/h3>\n

3.1.1 Preparation of Test Solution<\/h4>\n
Weigh 0.25 g of the sample (accurate to 0.00001 g) into a digestion tank. Add 3 mL of concentrated nitric acid and 9 mL of concentrated hydrochloric acid, cover and tighten the digestion tank, then place it in the microwave digestion system for digestion. Prepare a blank sample using the same method. After cooling, filter the solution and dilute it to the marked volume in a 25 mL volumetric flask. The solution is ready for on-machine testing.<\/div>\n
<\/div>\n
Microwave Heating Program<\/strong><\/div>\n
<\/div>\n
\n
\n\n\n\n\n\n\n\n\n\n
Step<\/th>\nTemperature (\u2103)<\/th>\nHolding Time (min)<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\n100<\/td>\n3<\/td>\n<\/tr>\n
2<\/td>\n120<\/td>\n3<\/td>\n<\/tr>\n
3<\/td>\n140<\/td>\n3<\/td>\n<\/tr>\n
4<\/td>\n160<\/td>\n3<\/td>\n<\/tr>\n
5<\/td>\n180<\/td>\n30<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

3.1.2 Preparation of Standard Solutions<\/h4>\n
    \n
  1. \n
    Preparation of Lead Standard Intermediate Solution<\/p>\n
    <\/div>\n

    Lead standard intermediate solution (1.0 \u03bcg\/mL): Accurately pipette 0.1 mL of the lead standard solution (1000 \u03bcg\/mL) into a 100 mL volumetric flask, dilute to the marked volume with (5+95) nitric acid solution, and mix well.<\/p><\/div>\n<\/li>\n

  2. \n
    Preparation of Lead Standard Series<\/p>\n
    <\/div>\n

    Accurately pipette 0.0, 0.5, 1.0, 1.5, 2.0, and 3.0 mL of the lead standard intermediate solution (1.0 \u03bcg\/mL) into separate 100 mL volumetric flasks respectively. Dilute each to the marked volume with (1+99) nitric acid solution to obtain lead standard series solutions with concentrations of 0.0, 5.0, 10.0, 15.0, 20.0, and 30.0 ng\/mL.<\/p><\/div>\n<\/li>\n<\/ol>\n

    3.2 Sample Testing<\/h3>\n
      \n
    1. Testing Conditions\n
      <\/div>\n

      Reference Conditions for Graphite Furnace Atomic Absorption Spectrophotometer<\/strong><\/li>\n<\/ol>\n

      <\/div>\n
      \n
      \n\n\n\n\n\n\n\n\n
      Element<\/th>\nLead<\/th>\n<\/tr>\n<\/thead>\n
      Wavelength (nm)<\/td>\n283.3<\/td>\n<\/tr>\n
      Spectral Bandwidth (nm)<\/td>\n0.4<\/td>\n<\/tr>\n
      Element Lamp Current (mA)<\/td>\n2<\/td>\n<\/tr>\n
      Background Correction Method<\/td>\nDeuterium Lamp<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n
      <\/div>\n
      Graphite Furnace Heating Program<\/strong><\/div>\n
      <\/div>\n
      \n
      \n\n\n\n\n\n\n\n\n
      Step<\/th>\nProcedure<\/th>\nTemperature (\u2103)<\/th>\nHeating Time (s)<\/th>\nHolding Time (s)<\/th>\n<\/tr>\n<\/thead>\n
      1<\/td>\nDrying<\/td>\n120<\/td>\n10<\/td>\n10<\/td>\n<\/tr>\n
      2<\/td>\nAshing<\/td>\n650<\/td>\n10<\/td>\n10<\/td>\n<\/tr>\n
      3<\/td>\nAtomization<\/td>\n1900<\/td>\n0<\/td>\n2<\/td>\n<\/tr>\n
      4<\/td>\nCleaning<\/td>\n2000<\/td>\n1<\/td>\n2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n
      <\/div>\n
        \n
      1. Sample Testing\n
        <\/div>\n

        Inject 10 \u03bcL of each lead standard series solution into the graphite furnace in ascending order of mass concentration. After atomization, measure the absorbance. Plot a standard curve with mass concentration as the abscissa and absorbance as the ordinate. Input the sample weight, then read and record the test results.<\/li>\n<\/ol>\n<\/div>\n