The smell of white pepper is aromatic and has certain medicinal value. Its taste is more spicy than black pepper, so it has stronger function of dispelling cold and stomach. It has the functions of sputum, greasy, and digestive ; its aromatic scent can make people appetite and increase appetite . It is a popular condiment; and pepper dishes are not easy to deteriorate, indicating that pepper has antiseptic Antibacterial effect , and it can solve fish porcine venom . Due to the medicinal value and flavoring effect of white pepper, it is made into many flavors, spices, spices (such as thirteen incense), etc., which are loved by consumers. Â .
However, most of the white pepper grows in high temperature and long-term moist areas. This growth environment also promotes the formation of some mycotoxins (aflatoxin AF). Aflatoxins (AF) are only produced when the humidity, temperature are suitable and well ventilated. . It is very likely to be infected with mold and produce aflatoxin, which may cause harm to the health of consumers. And recently, according to the Japan News Network, the Japanese Ministry of Health, Labor and Welfare announced that it will stop the circulation of white pepper in a company in Shandong, China. When the product was raided on the 7th of last month, it was found that 1 kg of white pepper contained up to 1 kg. 11 micrograms of carcinogenic aflatoxin. "
In the Chinese Pharmacopoeia, the limit of AFB1 in some Chinese herbal medicines is 5μg/kg, and the total limit of aflatoxin is 10μg/kg.
At present, the detection methods of aflatoxin AFT include high performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay. Liquid chromatography can accurately detect the small content of aflatoxin in Chinese herbal medicines. The aflatoxin ELISA kit allows rapid and accurate analysis of aflatoxin residues in the sample.
As a domestic supplier of mycotoxin detection technology and product services, Tellabs Test Application Lab focuses on food safety incidents, especially on the safety of mycotoxins. In response to the above situation, the following solutions are proposed.
Immunoaffinity column + KRC photochemical post-column derivatization
1 Introduction
The PriboFast aflatoxin B+G immunoaffinity column (No. IAC-010-3) selectively adsorbs toxins from the sample solution for very targeted purification of the toxin sample, followed by post-column derivatization with HPLC/FLD+KRC The system can effectively determine the concentration of aflatoxin B1, B2, G1, G2, and improve the accuracy and sensitivity of detection.
2. Immunoaffinity column / KRC derivative method features:
• Use highly specific antibodies.
• High column capacity, large column volume, and stable purification efficiency;
• High content of glue in the column to ensure stable recovery rate;
• Meet domestic and international standards
• Purified directly after ELISA, high performance liquid chromatography, fluorescence spectrometry, etc.
• for a variety of complex matrices • derivatization process easy to operate, without the use of photochemical derivatization derivatization reagent (post-column derivatization typically require the use of electrochemical reagents derived, high analysis cost, operational problems, equipment failure rate is higher).
• High recovery rate of over 90%
3. Introduction of the immunoaffinity column method :
1) Sample processing
• Accurately weigh 25g of powdered sample and dissolve it in 125ml of methanol/water (70/30);
Was added 5.0g of sodium chloride was stirred at a high speed homogenizer, extracted for 2 minutes;
. 4000r / min 5min centrifugation or filtration using fluted filter paper;
Take 15mL filtrate was diluted with 30mL of water was added, filtered with a glass microfiber filter paper;
Take diluted fluid test;
The immunoaffinity column connected to the lower 20.0mL glass Syringe. Accurately transfer 15.0 mL of sample extract into a glass syringe;
The air pressure of the pump is connected to the glass syringe, the solution was adjusted to a pressure / min flow rate of about 6mL slowly through the immunoaffinity column, until 2 ~ 3mL air through the cartridge;
. 10.0mL of water to the column was rinsed twice, all effluent was discarded, and 2mL ~ 3mL air through the cartridge;
Accurate added 1.0mL HPLC grade methanol, a flow rate of 1 mL / min ~ 2mL / min , the entire eluate collected in a glass test tube for detection.
• 2) Determination: Direct injection of HPLC, directly recording and calculating the concentration of aflatoxin B1B2G1G2 by a fluorescence detector with aflatoxin-specific chromatography column and KRC photochemical column derivatization;
Pribofast KRC post-column derivatizer and HPLC parameters (in accordance with GB23212-2008)
PriboFast KRC-25 post-column photochemical derivatizer UV lamp wavelength : 254 nm
HPLC- Column : Aflatoxin-specific column 150 x 4.6 mm; C-18
Flow phase : methanol-water 45:55
Flow rate : 1.0 mL/min      Â
Column temperature : 35 °C
Injection volume: 20μL
Fluorescence detector : λ-excitation wavelength: 365 nm λ-emission wavelength: 455 nm
Liquid chromatograph detection configuration;
High performance liquid chromatography with a fluorescence detector;
Pribofast KRC-25 post-column photochemical derivatization unit with 254nm nanotubes and 25m FTFE coils.
Aflatoxin-specific column C18 150 x 4.6 mm
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