1 Method Overview
After sample pretreatment, lead ions form a complex with sodium diethyldithiocarbamate (DDTC) under a specific pH condition. The complex is extracted and separated using 4-methyl-2-pentanone (MIBK), then introduced into an atomic absorption spectrometer for flame atomization. Absorbance is measured at a wavelength of 283.3 nm. Within a certain concentration range, the absorbance of lead is proportional to its mass content, and quantification is performed by comparison with a standard series.
2 Scope of Application
This method applies to the determination of lead in sodium pyrophosphate food additive.
3 Reference Standards
GB 25557-2010 National Food Safety Standard – Food Additive Sodium Pyrophosphate, Section A.10 Determination of Lead
4 Instruments, Equipment and Reagents
4.1 Instruments and Equipment
4.1.1 Analytical Instruments
表格
| No. | Name | Quantity | Technical Requirements | Accessories |
| 1 | Flame Atomic Absorption Spectrophotometer | 1 set | — | Lead Hollow Cathode Lamp |
| 2 | Air Compressor | 1 unit | Rated exhaust pressure: 0.3 MPa | — |
| 3 | Acetylene Cylinder | 1 cylinder | Purity ≥ 99.99% | — |
