Lincomycin ELISA Test Kit

Catalog No. LSY-10045

1. Principle

The test kit is based on the competitive enzyme immunoassay for the detection of Lincomycin in the sample. The coupling antigen is pre-coated on the micro-well stripes. The Lincomycin in the sample and the coupling antigens pre-coated on the micro-well stripes compete for the anti-Lincomycin antibodies. After the addition of the enzyme conjugate, the TMB substrate is added for coloration. The optical density (OD) value of the sample has a negative correlation with the Lincomycin in it. This value is compared to the standard curve and the Lincomycin residues is subsequently obtained.

2. Technical specifications

Sensitivity: 0.1 ppb

Incubator temperature:  25℃

Incubator time:  30min～15min

Detection limit

Tissue 0.4 ppb

Feed 1 ppb

Honey 2 ppb

Cross-reaction rate

Lincomycin 100%

Recovery rate

Tissue.Honey ……………………………………………………………100%±25%

Feed 95±25%

3. Components

1） Micro-well strips: 12 strips with 8 removable wells each

2） 6× standard solution (1 mL each): 0 ppb, 0.1ppb, 0.3 ppb, 0.9 ppb, 2.7 ppb,8.1 ppb

3） Enzyme conjugate (7 mL) red cap

4） Antibody working solution (7 mL) blue cap

5） Substrate A solution (7 mL) white cap

6） Substrate B solution (7 mL) black cap

7） Stop solution (7 mL) yellow cap

8） 20x concentrated washing buffer (40 mL)  white cap

9） 20× concentrated sample extraction solution (50 mL) ………………transparent cap

4. Materials required but not provided

1) Equipments:microplate reader, printer, homogenizer, vortex, oscillator, centrifuge, measuring pipets, incubator, balance (a sensibility reciprocal of 0.01 g)

2) Micropipettors: single-channel 20-200 µL and 100-1000 µL, and multi-channel 250 µL;

5. Sample pre-treatment

Instructions(The following points must be dealt with before the pre-treatment)

1) Only the disposable tips can be used for the experiments and the tips must be changed when used for absorbing different reagents;

2) Before the experiment, each experimental utensil must be clean and should be re-cleaned if necessary, in order to avoid the contamination that interferes with the experimental results.

Solution preparation before sample pre-treatment:

1)  Sample extraction solution:

1 part 20x concentrated sample extraction solution + 19 parts deionized water.

Samples preparation

5.1 Tissue (Chicken/liver, Pork/liver, shrimp, fish etc.)

1. Weigh 2.0 ±0.05 g homogenized tissue sample into 50ml centrifuge tube.

2. Add 6ml sample extraction solution, shake for 2 min, centrifuge at 4000 r/min at 15 ℃ for 10 min.

3. Take 50µL up-layer liquid for analysis.

Fold of dilution of sample:4            

5.2 Feed

1. Take 1.0 ± 0.05 g grinded sample into 50ml centrifuge tube.

2. Add 5ml sample extraction solution, shake for 1min, centrifuge at above 4000 r/min at 15 ℃ for 10 min

3. Take 200ul supernatant (upper layer), add 200ul sample extraction solution, shake to even. Take 50 µL for further analysis.

Fold of dilution of sample: 10    

5.3 Honey

1. Take 1.0 ± 0.05 g honey sample into 50ml centrifuge tube.

2. Add 5ml sample extraction solution, shake for 1min, centrifuge at above 4000 r/min at 15 ℃ for 10 min

3. Take 200ul supernatant (upper layer), add 600ul sample extraction solution, shake to even. Take 50 µL for further analysis.

Fold of dilution of sample:20   

6. ELISA procedures

Instructions

1.   Bring all reagents and micro-well strips to the room temperature (20-25℃).

2. Return all reagents to 2-8℃ immediately after use.

3. The reproducibility of the ELISA analysis, to a large degree, depends on the consistency of

plate washing. The correct operation of plate washing is the key point in the procedures of ELISA.

4. For the incubation at constant temperatures, all the samples and reagents must avoid light exposure, and each microplate should be sealed by the cover membrane.

Operation procedure

1. Bring test kit to the room temperature (20-25 ℃) for at least 30 min, note that each reagent must be shaken evenly before use; put the required micro-well strips into plate frames. Re-sealed the unused microplate, stored at 2-8 ℃, not frozen;

2. Solution preparation: dilute 40 mL of the concentrated washing buffer (20 × concentrated) with the deionized water at 1:19 (1 part concentrated washing buffer (20 ×) + 19 parts deionized water), or prepare as quantity needed.

3. Numbering: number the micro-wells according to samples and standard solution; each sample and standard solution should be performed in duplicate; record their positions;

4. Add 50 µL of the sample or the standard solution into separate duplicate wells, then add enzyme conjugate, 50 µL/well; and antibody working solution, 50 µL/well. Mix gently by shaking the plate manually, seal the microplate with the cover membrane, incubate at 25 ℃ for 30 min.;

5. Pour the liquid out of microwell, wash the microplate with the diuluted washing buffer at 250 µL/well for four to five times. Each time soak the well with the washing buffer for 15-30 sec, flap to dry with absorbent paper (if there are the bubbles after flapping, cut them with the clean tips).

6. Coloration: add 50 µL of substrate A solution and 50 µL B solution into each well. Mix gently by shaking the plate manually, andincubate at25 ℃ for 15 min at dark for coloration;

7. Determination: add 50 µL stop solution into each well. Mix gently by shaking the plate manually. Set the wavelength of the microplate reader at 450 nm to determine the OD value of every well. (Recommend to read the OD value at the dual-wavelength 450/630 nm within 5 min).

7. Result judgment

There are two methods to judge the results; the first one is the rough judgment, while the second is the quantitative determination. Note that the OD value of the sample has a negative correlation with Lincomycin concentration in the sample.

7.1 Qualitative determination

The concentration range (ng/mL) can be obtained from comparing the average OD value of the sample with that of the standard solution. Assuming that the OD value of the sample Ⅰ is 0.238, and that of the sample Ⅱ is 0.946, the OD value of standard solutions is: 1.845 for 0 ppb, 1.542 for 0.1 ppb, 1.130 for 0.3ppb, 0.635 for 0.9ppb, 0.326 for 2.7ppb, 0.156 for 8.1ppb, accordingly the concentration range of the sample Ⅰ is 2.7 to 8.1ppb, and that of the sample Ⅱ is 0.3 to 0.9ppb.

7.2Quantitative determination

The mean values of the absorbance values obtained for the average OD value (B) of the sample and the standard solution divided by the OD value (B0) of the first standard solution (0 standard) and subsequently multiplied by 100%, that is

Percentage of absorbance value =	B	×100%
	B0

B—the average (double wells) OD value of the sample or the standard solution

B0—the average OD value of the 0ng/mL standard solution

Draw the standard curve with the absorption percentages of the standard solutions and the semilogarithm values of the Lincomycin standard solutions (ng/mL) as Y- and X-axis, respectively. Read the corresponding concentration of the sample from the standard curve by incorporating its absorption percentage into the standard curve. The resulting value is subsequently multiplied by the corresponding dilution fold, finally obtaining the Lincomycin concentration in the sample.

Using the professional analyzing software of this kit will be more convenient for the accurate and rapid analysis of a large amount of samples. (Please contact us for this software)

8. Precautions 

1. The room temperature below 25 ℃ or the temperature of the reagents and the samples being not returned to the room temperature (20-25 ℃) will lead to a lower standard OD value.

2. Dryness of the microplate in the washing process will be accompanied by the situations including the non-linear standard curves and the undesirable reproducibility; So continue to next step immediately after washing.

3. Mix evenly, otherwise there will be the undesirable reproducibility.

4. The stop solution is the 2 M sulfuric acid solution, avoid contacting with the skin.

5. Do not use the kit exceeding its expiry date. The use of diluted or adulterated reagents from the kits will lead to the changes in the sensitivity and the detecting OD values. Do not exchange the reagents from the kits of different lot numbers to use.

6. Put the unused microplate into an auto-sealing bag to re-seal it. The standard substance and the colourless color former is light sensitive, and thus they cannot be directly exposed to the light.

7. Discard the colouration solution with any color that indicates the degeneration of this solution. The detecting value of the 0 standard solution (0 ppb) of less than 0.5 indicates its degeneration.

8. The optimum reaction temperature is 25 ℃, and too high or too low temperatures will result in the changes in the detecting sensitivity and OD values.

9. Storage and expiry date

Storage: store at 2-8 ℃, not frozen.

Expiry date: 12 months; date of production is on box.

Remarks: If the vacuum package of microtiter plates has leakage, the microtiter plate is normal and effective, do not affect the experimental result. Please feel free to use.