Sodium iodide (CAS 7681-82-5), dichloromethane
(CAS 75-09-2), and methanol (CAS 67-56-1) were purchased from Macklin
Biochemical Co., Ltd. (Shanghai, China). PS NPs with a nominal size
of 200 nm were purchased from Beijing Zhongkeleiming Technology Co.,
Ltd. (Beijing, China). PVC (CAS 9002-86-2), PMMA (CAS 9011-14-7),
PP (CAS 9003-07-0), PS (CAS 9003-53-6), PE (CAS 9002-88-4), PET (CAS
25038-59-9), and PA (CAS 63428-83-1) were purchased from Macklin Biochemical
Co., Ltd. (Shanghai, China). The polymer granules were frozen with
liquid nitrogen, milled with a grinder for 30 min, and separated with
50, 100, and 500 mesh stainless steel sieves to harvest fine polymer
powders with a size of 50–100 mesh and less than 500 mesh.
Stainless steel membranes (1000, 50, and 1 μm) were purchased
from Shuangte Filter Equipment Co. (Hebei, China). The polymer powders
were cleaned with methanol several times, filtered with stainless
steel membranes, and then dried in an oven at 65 °C. The purpose
of cleaning with methanol is to remove possible dissolved organic
matters, which had no significant effect on the surface morphology
and size of these powders (Figure S1 ).
These polymer powders were used for calibration curves and recovery
determination. When preparing polymer powders with low calibration
concentrations, it is difficult to weigh them directly. To solve this
problem, the polymer powder was dispersed in a mixture of methylene
chloride and methanol to facilitate the weighing of small amounts
of polymer. The stock solution (10 g/L) was continuously diluted to
obtain a plastic dispersion of 2–1000 mg/L, as described inText S1 .
(CAS 75-09-2), and methanol (CAS 67-56-1) were purchased from Macklin
Biochemical Co., Ltd. (Shanghai, China). PS NPs with a nominal size
of 200 nm were purchased from Beijing Zhongkeleiming Technology Co.,
Ltd. (Beijing, China). PVC (CAS 9002-86-2), PMMA (CAS 9011-14-7),
PP (CAS 9003-07-0), PS (CAS 9003-53-6), PE (CAS 9002-88-4), PET (CAS
25038-59-9), and PA (CAS 63428-83-1) were purchased from Macklin Biochemical
Co., Ltd. (Shanghai, China). The polymer granules were frozen with
liquid nitrogen, milled with a grinder for 30 min, and separated with
50, 100, and 500 mesh stainless steel sieves to harvest fine polymer
powders with a size of 50–100 mesh and less than 500 mesh.
Stainless steel membranes (1000, 50, and 1 μm) were purchased
from Shuangte Filter Equipment Co. (Hebei, China). The polymer powders
were cleaned with methanol several times, filtered with stainless
steel membranes, and then dried in an oven at 65 °C. The purpose
of cleaning with methanol is to remove possible dissolved organic
matters, which had no significant effect on the surface morphology
and size of these powders (
These polymer powders were used for calibration curves and recovery
determination. When preparing polymer powders with low calibration
concentrations, it is difficult to weigh them directly. To solve this
problem, the polymer powder was dispersed in a mixture of methylene
chloride and methanol to facilitate the weighing of small amounts
of polymer. The stock solution (10 g/L) was continuously diluted to
obtain a plastic dispersion of 2–1000 mg/L, as described in
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