Table 2.
Recoveries and detection limits for amorphous SiO2-NPs.
| Detection method |
Digestion method |
SiO2 source |
Matrix | Recovery ± s.d. (%) |
BEC | LOQ | LOD |
|---|---|---|---|---|---|---|---|
| (µg SiO2 L−1) | |||||||
| ICP-OES | KOH0.1 | colloidal | water | 85 ± 2 | 24.5 | 80.1 | 41.1 |
| KOH0.5 | DMEM | 84 ± 20 | 48.2 | 216.3 | 98.6 | ||
| KOH1.0 | fumed | water | 114 ± 25 | 63.7 | 67.6 | 64.8 | |
| colloidal | tomato saucea | 124 ± 5 | n.d. | n.d. | n.d. | ||
| food grade | seasoninga | 95 ± 13 | n.d. | n.d. | n.d. | ||
| RT + KOH1.0 | colloidal | water | 84 ± 4.9 | 113 | 296 | 168 | |
| fumed | 105 ± 1.4 | 113 | 296 | 168 | |||
| Colorimetry | RT + KOH0.1 | colloidal | 111 ± 7 | 115 | 264 | 148 | |
| fumed | 67 ± 2 | 22 | 430 | 144 | |||
| RT + KOH1.0 | 76 ± 9 | 120 | 307 | 176 | |||
Colloidal Stöber SiO2-NPs; fumed Aerosil® SiO2-NPs; and food grade SiO2, also known as E551. The SiO2-NPs were analyzed in matrices of increasing complexity: water, cell culture medium (DMEM), potato seasoning, and tomato sauce. The numbers in the digestion method names are the KOH concentrations used in mol L−1.
s.d.: standard deviation. n.d.: not determined. BEC: background equivalent concentration. LOD: instrument limit of detection. LOQ: instrument limit of quantification. RT: room temperature. ICP: Inductively coupled plasma – optical emission spectrometry. aThe food matrix was pre-digested as mentioned in section Pre-digestion of samples containing food matrix. Potato seasoning and tomato sauce recovery relative to mass after pre-digestion of the food matrix.