Determination of Pb, Ca, Ti and Al Content in Iron Powder and Tin-based Alloy Welding Powder
1 Sample solution preparation：
2 Experimental equipment and reagents：
4 Standard solution preparation
5 Standard curve
0.2g sample (precision to 0.0001g) was weighed and placed in a 250mL high neck beaker, 10mL aqua regia (HCl: HNO3 = 3:1) was added, covered with glass lid, heated on hot plate until the sample digests. Then, it was removed for cooling, transferred to a 25 mL volumetric flask, rinsed and made up to the volume with deionized water, shaken well, spared for later use.
2 Experimental equipment and reagents：
AA7000 series atomic absorption spectrophotometer (with Pb, Ca, Ti, Al hollow cathode lamp, EWAI Inc.)
Temperature-controlled hot plate
Nitric acid (HNO3): excellent grade purity
Hydrochloric acid (HCl): excellent grade purity
Lead standard solution (National Reference Materials Research Center)
Calcium standard solution (National Reference Materials Research Center)
Titanium standard solution (National Reference Materials Research Center)
Aluminium standard solution (National Reference Materials Research Center)
3 Instrument conditionsTemperature-controlled hot plate
Nitric acid (HNO3): excellent grade purity
Hydrochloric acid (HCl): excellent grade purity
Lead standard solution (National Reference Materials Research Center)
Calcium standard solution (National Reference Materials Research Center)
Titanium standard solution (National Reference Materials Research Center)
Aluminium standard solution (National Reference Materials Research Center)
| Parameter | Wavelength （nm） |
Slit width（nm） | Burner height（mm） | Fuel gas flow rate（L/min） | Lamp current（mA） | Flame type |
| Pb | 283.3 | 0.2 | 10 | 1.5 | 3.0 | Air – acetylene |
| Ca | 422.7 | 0.2 | 10 | 1.5 | 3.0 | Air – acetylene |
| Ti | 364.2 | 0.2 | 8 | 3.0 | 3.0 | Air – acetylene |
| Al | 309.3 | 0.2 | 8 | 3.0 | 3.0 | Air - acetylene |
4 Standard solution preparation
| Element | Concentration（μg/mL） | ||||
| Pb | 0 | 0.5 | 1.0 | 2.0 | 3.0 |
| Ca | 0 | 0.5 | 1.0 | 2.0 | 3.0 |
| Ti | 0 | 5.0 | 10.0 | 15.0 | |
| Al | 0 | 2.0 | 4.0 | 8.0 | 10.0 |
5 Standard curve
 Pb Curve equation：y=0.02379*x+0.00086 Linearity coefficient：1.00000 |
 Ca Curve equation：Y=0.08469*X+0.00431 Linearity coefficient：0.99970 |
 Ti Curve equation：Y=0.00076*X+0.00107 Linearity coefficient：0.99990 |
 Al Curve equation：Y=0.00323*X-0.00051 Linearity coefficient：0.99960 |
