Determination of Phthalates Plasticizing in Food
1. Application Range
It is suitable for the determination of oil phthalate compounds (rapeseed oil is used as sample matrix in this experiment).
Reference: SN/T 3147-2017 Determination of Phthalate Estates in Exported Foods
2. Extraction Steps
1) take 5 g samples in glass tube, add 2 mL acetonitrile saturated n-hexane, mix with vortex , then add 4 n-hexane saturated acetonitrile. Mix by vortex, ultrasound for 10 min, centrifuge for 5 min (3000r/ min), carefully transfer the lower layer solution to another glass tube; Add 4 n-hexane saturated acetonitrile, repeat extraction once and combine two extracts.
2) Put extract in 40℃ water bath to dry, accurately add 5 mL acetonitrile and mix by vortex. Add it in Welchrom®QuEChERS purification tube (P/N：00533-20020), mix by vortex, centrifuge for 5 min (3000r/) and take the supernatant to be tested.
3. Chromatographic Conditions
3.1 GC Conditions
Column: WM-5MS,30m*0.25mm*0.25μm
Injection inlet temperature: 260℃
Temperature program: initial column temperature 60℃, maintain 1 min; rise at 20℃/ min to 220℃, maintain 1 min; and then rise at 5/ min to 250, maintain 1 min; rise at 20℃/ min to 290℃, maintain 7.5 min.
Carrier gas: high-purity helium (purity >99.999%)
Injection way: splitless injection
Injection volume: 1μL
3.2 MS Conditions
Ionizing method: electron bombardment ionization source (EI)
Ionizing energy :70 Ev
Transmission line temperature :280℃
Ion source temperature :230℃
(b) Monitoring: ion scanning (SIM)
Solvent delay: 7.5 min
4. Chromatogram or Result of Spike Recovery
Fig 1. Chromatogram of 0.125μg/mL mixed standards phthalate esters
Table 1 Related Peak Information
| No. | Product | Retention | Width | Area |
| 1 | DMP | 7.995 | 0.026 | 231015 |
| 2 | DEP | 8.84 | 0.022 | 215986 |
| 3 | DIBP | 10.624 | 0.026 | 331212 |
| 4 | DBP | 11.384 | 0.028 | 240580 |
| 5 | DMEP | 11.73 | 0.029 | 80356 |
| 6 | BMPP | 12.442 | 0.055 | 144812 |
| 7 | DEEP | 12.807 | 0.034 | 65897 |
| 8 | DPP | 13.176 | 0.032 | 149986 |
| 9 | DHXP | 15.321 | 0.051 | 97533 |
| 10 | BBP | 15.498 | 0.038 | 75616 |
| 11 | DBEP | 16.971 | 0.038 | 20408 |
| 12 | DCHP | 17.669 | 0.035 | 61322 |
| 13 | DEHP | 17.833 | 0.033 | 51514 |
| 14 | DPhP | 17.982 | 0.033 | 53156 |
| 15 | DNP | 18.83 | 0.024 | 16379 |
| 16 | DNOP | 19.435 | 0.028 | 38063 |
Fig 2. Chromatogram of blank solvent
Fig 3. Chromatogram of purified rapeseed oil samples
Fig 4. Chromatogram of purified rapeseed oil samples at 0.05mg/kg
Table 2. Recovery rate of spiked samples
| No. | Name | Width | Area |
| 1 | DMP | 91.08% | 4.33% |
| 2 | DEP | 92.83% | 0.24% |
| 3 | DIBP | 64.94% | 0.85% |
| 4 | DBP | 84.56% | 2.40% |
| 5 | DMEP | 98.81% | 0.47% |
| 6 | BMPP | 94.82% | 4.31% |
| 7 | DEEP | 111.22% | 4.07% |
| 8 | DPP | 93.01% | 0.12% |
| 9 | DHXP | 83.75% | 0.11% |
| 10 | BBP | 133.48% | 5.74% |
| 11 | DBEP | 138.31% | 1.07% |
| 12 | DCHP | 87.88% | 0.42% |
| 13 | DEHP | 75.59% | 4.82% |
| 14 | DPhP | 109.14% | 1.41% |
| 15 | DNP | 72.99% | 3.40% |
| 16 | DNOP | 68.25% | 0.64% |
5. Ordering Information of Related Products
| P/N | Name | Specification |
| 00533-20020 | Purification tube | Welchrom® QuEChERS Purification tube-2ml，AOAC method，150mg MgSO4，50mg PSA，50mg C18E，used in fat and wax fruits and vegetables，100/pk |
| 03904-22001 | GC column | WM-5MS, 30m*0.25mm*0.25μm |