As the storm of plasticizers intensified, the Ministry of Health listed 17 kinds of phthalate esters including bis (2-ethyl) hexyl phthalate (DEHP) on June 1, 2011 "List of non-edible substances that may be illegally added in food and easily misused food additives (sixth batch)."
Dima Technology established the RP-HPLC determination of 6 phthalates (BBP, DBP, DEHP, DNOP, DINP, and DIDP) that are prohibited from contact with food in EU Directive 2007/19 / EC in 2008. Method, I will share this method with my colleagues, hoping to provide a new analysis path for phthalate detection.
Determination of Phthalates in Milk
1 Scope of application
Suitable for the detection of phthalates in milk and dairy products
2 Sample preparation / extraction
2.1 Weigh accurately 2.0g of milk sample into a glass tube with a stopper, add 2.0mL of methanol and 4.0mL of n-hexane-methyl tert-butyl ether (V / V = â€‹â€‹1: 1), and vortex to extract for 1min, Centrifuge at 3000 r / min for 2 min, take the supernatant, and then repeat the extraction once with 4.0 mL of n-hexane-methyl tert-butyl ether (V / V = â€‹â€‹1: 1), and combine the two supernatants. Nitrogen was blown to dryness in a water bath at 45 â„ƒ, dilute to 4.0 mL with n-hexane, shake well, freeze after capping for 30 min, then centrifuge at 3000 r / min for 2 min, take the supernatant, and then dilute to volume with n-hexane to 4.0mL, mixed, and then divided into 2 parts, one part is used for purification of BBP and DBP, and the other part is used for purification of DEHP, DNOP, DINP and DIDP.
3 Sample purification
3.1 Purification of BBP and DBP Separate 2.0mL of the sample solution extracted in the previous section, add 2.0mL of acetonitrile, vortex and extract for 1min, leave the n-hexane layer after standing for separation, then add 1.0mL of n-hexane, shake and separate After the layer was discarded, the n-hexane layer was discarded, and the acetonitrile phase nitrogen was blown to dryness, and the volume was adjusted to 1.0 mL with methanol and injected.
3.2 Purification of DEHP, DNOP, DINP and DIDP-ProElut Silica 500 mg / 3 mL
(1) Activation: Add 40 mL of 0.7% ethyl acetate in n-hexane and 5 mL of n-hexane in sequence, and discard the effluent;
(2) Sample loading: Add 2.0mL of the sample fluid extracted in the previous section, and discard the effluent
(3) Rinse: add 3.0mL of 0.7% ethyl acetate in n-hexane, and discard the effluent
(4) Elution: 19mL of 0.7% ethyl acetate in n-hexane was used for elution. The effluent was collected, blown to dryness in a 45 Â° C water bath with nitrogen, and volumetrically injected with 1.0mL of methanol.
4 Analysis conditions
Column: Platisil ODS, 250 mm Ã— 4.6 mm, 5 Î¼m (Cat. # 99503)
Flow rate: 1.0 mL / min
Detector: * UV 224nm
Column temperature: 30 â„ƒ
Injection volume: 20 Î¼L
Mobile phase: acetonitrile: water = 99: 1 (volume ratio)
5 Experimental results
Chromatogram of milk sample after solid phase extraction
Chromatogram of standard retained on Platisil ODS column (C)
1-BBP 30Î¼g / mL, 2-DBP 0.30Î¼g / mL, 3-DEHP 1.5Î¼g / mL,
4-DNOP 9.0Î¼g / mL, 5-DINP 9.0Î¼g / mL, 6-DIDP 9.0Î¼g / mL
About Dima Technology Co., Ltd.
Dima Technology is a well-known chromatographic consumable manufacturer dedicated to R & D and manufacturing of scientific and efficient chemical analysis products, providing comprehensive services and comprehensive solutions. It has always been in many technical fields such as chromatographic packing research and development, chromatographic column manufacturing and related separation products Maintain the world's advanced level. Core technology products include: liquid chromatography columns, gas chromatography columns, solid phase extraction columns, chromatography solvents and chemical standards.
The company has strong R & D strength, especially in the world's leading position in the production technology of HPLC chromatography columns and SPE small columns. Its products are sold at home and abroad, and are deeply trusted and praised by users. With the excellent performance of Dima products in the market and the unanimous praise of the majority of users, Dima stands out among many consumable parts manufacturers at home and abroad, and was awarded "China's most influential consumable parts manufacturers".
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