HPLC detection of aflatoxins

Aflatoxins (AFT) are a class of chemically similar compounds that are all derivatives of dihydrofuranocoumarin. Aflatoxin is a secondary metabolite produced mainly by Aspergillus flavus (parasiticus). The occurrence of aflatoxin is highest in foods and feeds in hot and humid areas.

First, HPLC detection of aflatoxin experimental materials:

1.1 Immunoaffinity column: Bona-Agen Aflatoxin total immunoaffinity column Order No.: HC09001

1.2 Column: Venusil MP C18 (4.6*150mm, 5μm), order number: VA951505-0

Second, HPLC detection of aflatoxin test methods:

1.1 Preparation of Mixed Reference Solution Precise amounts of aflatoxin mixed standard (1.0μg/mL, 0.3μg/mL, 1.0μg/mL, 0.3μg/mL for aflatoxin B1, B2, G1, and G2, respectively) ) 1mL, set in a 10mL volumetric flask, diluted with methanol to the mark as a stock solution. Precisely take a stock solution of 1mL, set 50mL volumetric flask, diluted with 70% methanol solution to the mark, that is, too.

1.2 preparation of the test solution to take the test powder about 10g, accurately weighed, add 2g of sodium chloride, accurately add 70% methanol solution 100mL, ultrasonic treatment for 20 minutes, centrifuge 5 minutes (centrifugal speed 8000 rev / min), Precisely take 10 mL of the supernatant and set it in a 50 mL volumetric flask. Dilute it to the mark with water and shake it. Accurately take 25 mL. Pass the immunoaffinity column. The flow rate is 2-3 mL per minute. Rinse with 5 mL of water. The washing solution is discarded. The air was allowed to enter the column and eluted with 1.4 mL of methanol twice. The eluate was collected, and the volume was adjusted to 2 mL with water.

1.3 Assay Accurately draw 20 μl of the above mixed reference solution and 20 μl of the test solution. Inject into the liquid chromatograph to measure the peak area. Read out from the standard curve the corresponding aflatoxins B1, B2, and G1. The amount of G2, calculated, that is, too.

Third, high-performance liquid chromatography detection of aflatoxin chromatographic conditions:

Instrument: High Performance Liquid Chromatography (LC600)

Fluorescence Detector: Photochemical Post Column Derivatives (Nanjing Kote)

Column: Venusil MP C18 (4.6*150mm), order number: VA951505-0

Injection volume: 20μl; column temperature: 40°C; flow rate: 1.1mL/min

Fourth, high performance liquid chromatograph technical parameter:

High Performance Liquid Chromatograph/LC-P600 High-voltage Constant-current Pump LC-P600 High-pressure constant-current pump is a microprocessor-controlled reciprocating double-plunger parallel pump with high working pressure, small pulsation, stable and reliable, and easy operation. Features. Its mechanical components are computer-aided design, and all major components are manufactured in the world's most advanced CNC machining centers. Therefore, it has features such as high processing precision, good sealing performance of the pump body, and good interchangeability of parts.

The plunger rod uses a floating guide structure and the drive cam is made of high-strength alloy steel. Microprocessor-controlled microstep drive circuit is used to make the stepper motor driving the pump run smoothly, with low noise and large speed adjustment range. LC-P600 high pressure constant flow pump in the pressure of 0 ~ 42Mpa range, the flow rate can be from 0.001mL/min to 9.999mL/min. This satisfies the need for routine analysis to microflow analysis.

In single pump isokinetic analysis, various operating modes can be changed through four function keys according to the prompts of the full Chinese character display screen on the instrument, and the flow, upper and lower pressure limits, and continuous working time can be conveniently set. Pressure unit and other parameters.

The LC-P600 high-pressure constant-current pump has a process monitoring function. The microprocessor controls the flow of the pump in real time and detects the infusion pressure. In the event of pressure overrun, the alarm will automatically stop the pump.

The LC-WS100 workstation can be used to control the operation of up to four pumps through the RS232 interface to establish a multivariate gradient analysis system.

The integral structure of LC-P600 high-pressure constant-current pump adopts a modular design, including the mechanical part and the circuit part can be installed and disassembled independently, so the fault inspection and exchange are very convenient.

LC-P600 high-pressure constant-current pump adopts double-plunger parallel pump structure, and double pump head alternately transfusion. With the same amount of infusion, its output pulse is much lower than that of the tandem pump, and the piston rod and seal life is twice as long as the conventional tandem pump.

High Performance Liquid Chromatograph/LC-UV600 UV Detector The LC-UV600 UV Detector uses a parallel double-cone hole flow cell. The sample cell and reference cell are completely in equal conditions. The cone-shaped design flow cell can increase the light energy passing through the cell hole under the same cell volume, which significantly reduces the static noise and signal drift of the instrument.

The optical path system adopts a precise positioning structure, so the accuracy is high and the offset is small. The xenon lamp holder and light path system adopts thermal isolation mounting technology, which reduces the settling time of the instrument and minimizes the influence of the heating of the xenon lamp on the light path system.

The control circuit uses a multi-microprocessor architecture to manage signal acquisition, data processing, system control, and communications, respectively. When the LC-UV600 UV detector is used for isocratic analysis, it can easily set parameters such as UV wavelength, filter constant, output range, and running time through the full Chinese character LCD screen and seven function keys. And can realize the function such as switching deuterium lamp, spectral scanning, starting analysis program.

Another major feature of this instrument is that the LC-UV600 UV detector uniquely uses a digital signal output line structure. Compared with conventional UV detector chromatogram signals, most of them use analog signal output or internal digital signal processing, and then converted into analog signals and output to chromatographic data processing devices, and then undergo analog-to-digital conversion. This multiple conversion will inevitably lead to signal distortion and interference. The LC-UV600 UV detector sends the digitized signal to the LC-WS600 workstation without loss through the RS232 interface for logarithmic conversion and integration processing.

The LC-UV600 UV Detector can be conveniently controlled by a graphical interface on the LC-WS600 workstation to control Xenon lamp switching, spectral scanning, relay switching, and wavelength scanning.