Vomitoxin嘔吐毒素(DON)-定量-ELISA-0.025~0.25 ppm

• 原理
  酵素連結免疫分析法Enzyme-linked immunosorbent assay (ELISA)，利用抗原和抗體之間專一性鍵結的特性，並加入顯色酵素和酵素受質，利用顯色的深淺，對檢體進行檢測的分析方法。ELISA可使用標準曲線法 (standard curve) 進行定量，透過檢體的吸光值與標準品進行比對，即可得到檢體的對應濃度。競爭法(competitive ELISA) 一般用於分子量較小的抗原檢測，在抗體數量固定的塑膠孔盤上，加入可鍵結的酵素抗原及檢體抗原，兩種抗原皆會競爭塑膠孔盤上抗體鍵結，當檢體中抗原含量越多，顯色也就越淺
  
  Vomitoxin嘔吐毒素，又稱脫氧雪腐鐮刀菌烯醇(deoxynivalenol, 簡稱DON)，屬於鐮刀黴菌毒素(新月毒素群)(trichothecenes)的一種，主要是由禾穀鐮孢菌(Fusarium graminearum)汙染大麥、小麥、玉米及相關的穀物飼料加工品所產生的天然毒素，DON最明顯的症狀是引起動物的嘔吐，此外，也會引起其他急性症狀，例如:腹痛、腹瀉、腸胃炎...等。
• 結果判讀
  極限:
  偵測極限(limit of detection, LOD)： 0.025 ppm 
  定量極限(limit of quantification, LOQ)：0.025 ppm 
  偵測範圍:0.025–0.25 ppm(樣品超過0.25ppm需重新稀釋及測量)
   
• 樣品準備與萃取(SAMPLE PREPARATION AND EXTRACTION)
  The sample to be tested should be collected according to accepted sampling techniques. The sample should be ground and thoroughly mixed prior to proceeding with the extraction. Store samples at 2-8°C (35-46°F) until analyzed.
  1. Obtain a representative sample. Grind the entire sample so that at least 75% of the ground material passes through a 20 mesh sieve, the particle size of a fine instant coffee.
  2. Using hand or mechanical means, vigorously shake 10 grams of ground sample in 50 mL of distilled or deionized water for 3  minutes.
  3. Let material set for 2-3 minutes to enable some of the sample to settle before filtering extract.
  4. Filter the extract by pouring at least 5 mL through a Whatman #1 filter (or Neogen filter syringe) and collecting the filtrate as a sample.
  5. The sample is ready for testing.
   
• 操作流程(TEST PROCEDURE)
  Allow all reagents to warm to room temperature 18–30°C (64–86°F) before use.
  1. Remove 1 red-marked mixing well for each sample to be tested plus 5 red-marked wells for controls, and place in the well holder.
  2. Remove an equal number of antibody-coated wells. Return antibody wells which will not be used immediately to the foil pack with desiccant and seal to protect the antibody. Mark one end of strip with a “1”, and place strip in the well holder with the marked end on the left. Do not mark the inside or bottom of the wells.
  3. Mix each reagent by swirling the reagent bottle prior to use.
  4. Place 100 µL of conjugate from the blue-labeled bottle in each red-marked mixing well. 
  5. Using a new pipette tip for each, transfer 100 µL of controls and samples to the red-marked mixing wells as described below. 

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  S1

  S2

  S3

  S4

  S5

  S6

  S7

  Strip 1

  S8

  S9

  S10

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  Strip 2

  6. Using a 12-channel pipettor, mix the liquid in the wells by pipetting it up and down 3 times. Transfer 100 µL to the antibody-coated wells. Mix by sliding the microwell holder back and forth on a flat surface for 10-20 seconds without splashing reagents from the wells. Incubate for 10 minutes at room temperature (18-30°C, 64-86°F). Discard red-marked mixing wells.
  7. Shake out the contents of the antibody wells. Fill the wells with distilled or deionized water and dump them out. Repeat this step 5 times, then turn the wells upside-down and tap out on a paper towel until the remaining water has been removed.
  8. Pour the needed volume of substrate from the green-labeled bottle into the green-labeled reagent boat.
  9. With new tips on the 12-channel pipettor, prime and pipette 100 µL of substrate into the wells and mix by sliding back and forth on a flat surface for 20 seconds.
  10. Incubate 10 minutes. Discard remaining substrate and rinse the reagent boat with water.
  11. Pour Red Stop solution from the red-labeled bottle (same volume as the substrate) into the red-labeled reagent boat.
  12. Eject the excess substrate from the 12-channel pipettor, prime the tips, and pipette 100 µL of Red Stop to each well. Mix by sliding back and forth on a flat surface. Discard the tips.
  13. Wipe the bottom of the microwells with a dry cloth or towel and read in a microwell reader using a 650 nm filter. Air bubbles should be eliminated, as they could affect analytical results. Results should be read within 20 minutes after the addition of Red Stop.
  14. Read and calculate results using Neogen's Stat-Fax microwell reader. If using an EL301 reader or other strip/plate reader, calculate results using Neogen's Veratox for Windows software.

• 產品說明書：連結
• 操作手冊：連結
• 物質安全資料表(Safety Data Sheet; SDS)：中文連結、英文連結

參考規範：食品中污染物質及毒素衛生標準