CN117740768A

CN117740768A - 25 hydroxy vitamin D dissociation liquid and application thereof in magnetic particle chemiluminescence platform

Info

Publication number: CN117740768A
Application number: CN202311763936.5A
Authority: CN
Inventors: 张新; 仝艳艳; 王艳敏; 张�杰
Original assignee: Beijing Leadman Biochemistry Co ltd
Current assignee: Beijing Leadman Biochemistry Co ltd
Priority date: 2023-12-21
Filing date: 2023-12-21
Publication date: 2024-03-22

Abstract

The invention relates to 25 hydroxy vitamin D dissociation liquid and application thereof in a magnetic particle chemiluminescence platform, wherein the dissociation liquid comprises buffer solution, protein precipitant, N-dimethylformamide and sterilizing agent; the buffer solution is one or two selected from phosphate, glycine, citrate and 2- (N-imidazoline) ethane sulfonic acid buffer solution; the protein precipitant is one or two selected from tannic acid, picric acid, sulfosalicylic acid and trichloroacetic acid; the sterilizing agent is one or two selected from MIT, benzalkonium chloride and erythromycin. The buffer solution is a meta-acidic buffer solution, is added with an organic solvent N, N-dimethylformamide and a relatively mild, well water-soluble and low-toxic protein precipitant, has a simple formula, is prepared from the required raw materials which are commercially available, is easy to prepare, has stable properties of each component, is loose in storage condition, can be stored at room temperature, and can be stored independently for use. The dissociation liquid has good stability and can not influence immune reaction.

Description

25 hydroxy vitamin D dissociation liquid and application thereof in magnetic particle chemiluminescence platform

Technical Field

The invention belongs to the technical field of small molecule immunodetection, and particularly relates to 25-hydroxy vitamin D dissociation liquid and application thereof in a magnetic particle chemiluminescence platform.

Background

Vitamin D is closely related to the skeletal development, the autoimmune power, the cardiovascular health and other aspects of the human body, and deficiency, abnormal metabolism or excessive vitamin D can have great influence on the health, so that the accuracy of the test result is important to the aspects of clinically evaluating the basic level of the organism, making an intervention scheme and the like.

25 hydroxy vitamin D is the main form of vitamin D in serum, comprising 25 hydroxy vitamin D2 and 25 hydroxy vitamin D3, accounting for more than 80% -90% of the total amount of vitamin D, the main existing form in human body, reflecting the real level of vitamin D in human body.

Detection of 25 hydroxy vitamin D advantage:

1. it is contained in blood in active form 1,25 dihydroxyvitamin D (1, 25 (OH) ₂ D) 1000 times of (2);

2. the half-life period is long and can reach 2-3 weeks;

3. it has stable properties and is not directly affected by diet, life style, etc.

25 hydroxy vitamin D is a hydrophobic small molecule with a molecular weight of about 420 and almost all circulating 25 hydroxy vitamin D in serum in vivo is bound to vitamin D binding protein (88%) and albumin (12%). The key technology for detecting 25 hydroxy vitamin D is therefore to dissociate 25 hydroxy vitamin D from the binding protein.

At present, in a magnetic particle chemiluminescence kit for detecting VD at home and abroad, the dissociation method of VD mainly adopts the following two methods:

1. strong acid and strong base method the strong acid and strong base method is that the VD binding protein is denatured or conformational change occurs by too high or too low pH value, so that the VD binding protein is separated from the VD, and then the pH is neutralized.

The disadvantage of this method is that: at least two liquids are needed for preprocessing a sample, one dissociation liquid and one neutralization liquid are added, the composition of reagents is increased, two steps of sample adding are needed in a reaction flow, the operation is complex, and the sample detection speed is influenced; the pH value is not easy to control, the subsequent immune reaction is affected, and the repeatability of the sample detection result is poor.

2. Dissociation method using methanol and ANSA

The method has the defects of being too mild, weak in dissociation effect and incapable of thoroughly releasing 25 hydroxy vitamin D, and is unfavorable for detection sensitivity.

In addition, other methods, such as protein hydrolysis, are used in the literature and other detection platforms, which require too long a time. For example, an organic solvent dissolution method is adopted, ethanol or acetonitrile is used for extracting precipitated protein, precipitate is removed, supernatant containing VD is recovered for detection, and the method is difficult to realize full automation and cannot be applied to a magnetic particle chemiluminescence platform.

The sample dissociation method of other patents refers to a dissociation solution of VD in publication number CN 115774112a, guanidine hydrochloride is used to reversibly denature VD binding protein, propylene carbonate is used to loosen amino acids constituting the protein after denaturation to promote further dissociation of VD binding protein, and irreversible denaturation is promoted, wherein the dissociation solution and the sample are mixed first and then immunoreact with vitamin D during detection, and the dissociation solution can indeed improve the dissociation efficiency of protein, but the component is complex, the cost is higher, and the detection method is suitable for chromatography, and is not completely suitable for application in a magnetic particle chemiluminescence platform.

Disclosure of Invention

Aiming at the technical problems, the invention aims to provide 25 hydroxy vitamin D dissociation liquid and application thereof in a magnetic particle chemiluminescence platform. The 25 hydroxy vitamin D dissociation solution has the advantages of simple formula, stable property, quick and sufficient dissociation, no influence on immune reaction of antigen and antibody, high sensitivity, few processing steps and short reaction time, can be simultaneously incubated with a sample and the 25 hydroxy vitamin D antibody marked by alkaline phosphatase on the premise of no toxicity of raw materials, reduces the waiting time of the sample to obtain results, can be directly applied to a full-automatic magnetic particle chemiluminescence platform, and completely meets the clinical requirement on detection reagents.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a 25-hydroxy vitamin D dissociation liquid and application thereof, comprising buffer solution, protein precipitant, N-dimethylformamide and sterilizing agent;

the buffer solution is one or two selected from phosphate, glycine, citrate and 2- (N-imidazoline) ethane sulfonic acid buffer solution;

the protein precipitant is one or two selected from tannic acid, picric acid, sulfosalicylic acid and trichloroacetic acid;

the sterilizing agent is one or two selected from MIT (methyl isothiazolinone), benzalkonium chloride (dodecyl dimethyl benzyl ammonium chloride) and erythromycin (macrolide antibiotics).

Preferably, the buffer solution is citrate, and the concentration of the citrate in the dissociation solution is 10-200 mM; the protein precipitant is 5-sulfosalicylic acid, and the concentration of the 5-sulfosalicylic acid in the dissociation liquid is 0.5-2 wt%; the volume concentration of the N, N-dimethylformamide is 5% -20%; the sterilizing agent is MIT (methyl isothiazolinone), and the volume concentration of the sterilizing agent in the dissociation liquid is 0.05% -0.2%. The rest of the dissociation liquid is water.

Preferably, the pH value of the dissociation liquid is 3-6.

The 25 hydroxy vitamin D detection reagent for measuring the 25 hydroxy vitamin D content of a human body comprises the dissociation liquid (marked as R1), a 25 hydroxy vitamin D antibody-alkaline phosphatase reagent R2 (for short, a reagent R2), a 25 hydroxy vitamin D-biotin reagent R3 (for short, a reagent R3), a magnetic separation reagent, a calibrator, a quality control product and a chemiluminescent substrate liquid. In the following examples, 25 hydroxy vitamin D reagent R2, calibrator, quality control, chemiluminescent substrate were all from reagents manufactured by Lidemann company; the reagent R3 and the magnetic separation reagent are commercial products.

The invention provides an application of the dissociation liquid in a magnetic particle chemiluminescence platform, which comprises the following steps:

(1) Incubating the dissociation solution with the sample and alkaline phosphatase-labeled 25-hydroxyvitamin D antibody.

Preferably, the volume ratio of the dissociation liquid to the 25 hydroxy vitamin D sample and the alkaline phosphatase marked 25 hydroxy vitamin D antibody is 1 (0.2-1): 1-3; the volume of the 25-hydroxy vitamin D sample is 5-50 mu L, and the volume of the alkaline phosphatase-labeled 25-hydroxy vitamin D antibody is 30-90 mu L.

Preferably, the incubation time is 1 to 5 minutes.

(2) Adding 25 hydroxy vitamin D-biotin reagent R3 and a magnetic separation reagent into the incubated sample in the step (1), and continuously incubating for 5min at 37 ℃;

(3) Washing to remove unbound antibodies and impurities;

(4) Adding chemiluminescent substrate liquid, and measuring relative luminous intensity RLU after ALP catalyzes the substrate to emit light;

the relative luminous intensity RLU is inversely proportional to the concentration of the 25 hydroxy vitamin D antigen in a certain range, and the 25 hydroxy vitamin D content of the sample to be detected can be read from the standard curve by an interpolation method.

The method identification data of the 25 hydroxy vitamin D content of the human body measured by the 25 hydroxy vitamin D detection reagent (also called a kit) can reach the following indexes:

sensitivity: the minimum detection amount is less than 1.00ng/mL;

repeatability: the precision of the quality control product QC1 is 3.35 percent (n=10, the number of repetition is equal to 2.20 percent (n=10, the number of repetition is equal to) and is far lower than the industry requirement, so that the detection reagent using the dissociation agent has good repeatability in the experimental process;

correlation: the 129 samples were simultaneously detected using the kit of the inventive reagent and the Michael chemiluminescence magnetic particle immunoassay, the concentration of 25 hydroxyvitamin D was measured as ordinate, the result of the Michael chemiluminescence immunoassay was measured as abscissa, regression analysis was performed, the correlation equation was y= 1.0918x-0.4794, and the correlation coefficient R ² The statistical treatment results show that the correlation is good, = 0.9843;

the reagents in the examples were used to simultaneously detect 50 samples by liquid chromatography-mass spectrometry/mass spectrometry, and the correlation coefficients R of the two methodologies ² ＝0.9812, the correlation is good;

stability: the effective period of the kit can be as long as 12 months.

Compared with the prior art, the invention has the beneficial effects that:

(1) The 25 hydroxy vitamin D dissociation liquid provided by the invention is a meta-acid buffer, and is added with organic solvent N, N-dimethylformamide and relatively mild, good in water solubility and low-toxicity protein precipitant, so that the 25 hydroxy vitamin D dissociation liquid is simple in formula, the required raw materials are commercially available, the preparation is easy, the properties of each component are stable, the storage condition is loose, and the 25 hydroxy vitamin D dissociation liquid can be stored at room temperature and can be used independently. The dissociation liquid has good stability and can not influence immune reaction.

(2) The dissociation liquid can be used in a liquid phase reaction system, and can carry out immune reaction while dissociating a sample in the detection method, so that the detection rate of the sample is greatly improved, the repeatability and the accuracy of a detection result are facilitated, and the dissociation liquid is very suitable for being applied to a magnetic particle chemiluminescence platform. In the application of the magnetic particle chemiluminescence platform, the required sample size is small, and the sample size can reach the detection requirement by 10 uL.

(3) The buffer in the invention is preferably citrate, and citric acid plays a role of buffer on one hand and denatures proteins on the other hand. The protein precipitant is preferably 5-sulfosalicylic acid, is an organic reagent, has the characteristics of good water solubility, stability and low toxicity, can aggregate and precipitate the modified VD binding protein, further promotes dissociation of the VD and the VD binding protein, and promotes reversible denaturation of the protein to the precipitation direction. The N, N-dimethylformamide can be mixed with water and most organic solvents at will, has good dissolving capacity for various organic compounds and inorganic compounds, does not influence the dissolving capacity of inorganic salts in the reagent in water, can ensure that reactants in homogeneous phase reaction can be well dissolved in the solvents, and promotes the reaction to be carried out efficiently.

(4) The dissociation agent is an acidic reagent, can effectively release all 25 hydroxy vitamin D combined with the binding protein, has sufficient dissociation, has the detection time of less than 15min, and effectively shortens the waiting time; the sensitivity is high and is less than 1ng/mL, and the dissociation effect is good; chemiluminescent product with magnetic particles on the marketCorrelation R of products and liquid chromatography-mass spectrometry/mass spectrometry comparison ² Can reach more than 0.95. The dissociation effect is stable and uniform, the precision is less than 4%, the accuracy of clinical monitoring is greatly improved, the duration time is long, and the method can be directly applied to a magnetic particle chemiluminescence immunoassay platform. But will affect the overall system reaction rate.

(5) The dissociation liquid can meet the urgent clinical requirements of 25 hydroxy vitamin D on rapidness, accuracy, stability, high flux and low cost. The dissociative liquid provided by the invention has stable quality, can be stored at room temperature, greatly prolongs the shelf life of the product, has simple components, is easy to prepare, has good repeatability and has small individual difference.

Drawings

FIG. 1 is a graph showing the concentration-luminescence values of the standard for the detection of 25 hydroxy vitamin D from the dissociation solution of example 2;

FIG. 2 is a graph showing the concentration-luminescence value of the standard substance when the dissociation liquid of comparative example 1 of the present invention is used for detecting 25-hydroxyvitamin D.

FIG. 3 is a graph showing the concentration-luminescence value of the standard substance when the dissociation liquid of comparative example 2 of the present invention is used for detecting 25-hydroxyvitamin D.

Fig. 4 is a graph showing the concentration-luminescence value of the standard substance when the dissociation liquid of comparative example 3 of the present invention is used for detecting 25 hydroxy vitamin D.

FIG. 5 is a plot of correlation of 25 hydroxy vitamin D concentration with a contrast agent for the detection of 25 hydroxy vitamin D from the dissociation liquid in example 2 of the present invention.

FIG. 6 is a plot of the correlation of 25 hydroxy vitamin D concentration with the contrast agent for the detection of 25 hydroxy vitamin D using the dissociation liquid of comparative example 1.

FIG. 7 is a graph showing correlation analysis of 25 hydroxy vitamin D detected by dissociation liquid and liquid chromatography-mass spectrometry/mass spectrometry in example 2 of the present invention.

Detailed Description

The present invention is further explained below with reference to examples and drawings, but is not to be construed as limiting the scope of the present application.

Example 1

The invention provides a 25-hydroxy vitamin D dissociation liquid, which comprises citrate buffer solution, 5-sulfosalicylic acid protein precipitant, N-dimethylformamide and MIT (methylisothiazolinone) sterilizing agent.

The concentration of the citrate in the dissociation liquid is preferably 10 to 200mM, more preferably 40 to 60mM, and most preferably 50mM. The concentration of the 5-sulfosalicylic acid in the dissociation liquid is preferably 0.5wt% to 2wt%, more preferably 0.5wt% to 1wt%, and most preferably 1wt%. The volume concentration of the N, N-dimethylformamide in the dissociation liquid is preferably 5% to 20%, more preferably 10% to 20%, and most preferably 10%. The MIT (methylisothiazolinone) is preferably present in the dissociation liquid at a volume concentration of 0.05% to 0.2%, more preferably 0.05% to 0.1%, most preferably 0.1%.

In the present invention, the pH of the dissociation liquid is preferably 3 to 5, more preferably 4 to 5, and most preferably 4.5. The protein precipitation is facilitated under the acidic condition, the optimal binding site of the antibody is exposed, the combination of the dissociated 25 hydroxy vitamin D and the alkaline phosphatase marked 25 hydroxy vitamin D antibody is facilitated, and the detection sensitivity is improved.

Example 2

Preparation of 25 hydroxy vitamin D dissociation liquid

The preparation method of the 25-hydroxy vitamin D dissociation liquid is as shown in the following table 1 (water is used as solvent), and the preparation method is carried out after the preparation is completed, the preparation method is left at normal temperature.

TABLE 1 composition of 25 hydroxy vitamin D dissociation solution

Component name	Proportioning content/concentration
		Citrate buffer	50mM
N, N-dimethylDimethylformamide (v/v)	10％
		5-sulfosalicylic acid (w/v)	1％
Methyl isothiazolinone (v/v)	0.1％

The 25 hydroxy vitamin D detection reagent for measuring the 25 hydroxy vitamin D content of the human body comprises the dissociation liquid (marked as R1), a 25 hydroxy vitamin D antibody-alkaline phosphatase reagent R2 (for short, a reagent R2), a 25 hydroxy vitamin D-biotin reagent R3 (for short, a reagent R3), a magnetic separation reagent, a calibrator, a quality control product and a chemiluminescent substrate liquid.

Comparative examples 1 to 2

Preparation of 25 hydroxy vitamin D dissociation liquid:

TABLE 2 composition of 25 hydroxy vitamin D dissociation solution

Component name	Proportioning content/concentration
		Citrate buffer	50mM
N, N-dimethylformamide (v/v)	Comparative example 1:5%, comparative example 2:20 percent of
		5-sulfosalicylic acid (w/v)	Comparative example 1:0.5%, comparative example 2:2%
Methyl isothiazolinone (v/v)	0.1％

Comparative examples 3 to 4

The kits of comparative examples 3 to 4 were respectively finished kits that had been obtained evidence. Wherein, in comparative example 3, the dissociation solution R1 is 0.5M sodium hydroxide, and the MES buffer solution with the component of the reagent R3 of pH6.0 is added with amphoteric reagent: 10% absolute ethanol and 0.5% DTT as reducing agent.

The dissociation solution R1 in comparative example 4 includes pretreatment solution 1 and pretreatment solution 2, wherein pretreatment solution 1 is Tris buffer, and pretreatment solution 2 is 0.5M sodium hydroxide.

Example 3

The invention provides a use method of the dissociation liquid, which comprises the following steps: the dissociation solution was mixed with a 25 hydroxy vitamin D sample and an alkaline phosphatase-labeled 25 hydroxy vitamin D antibody R2 (abbreviated as reagent R2).

In the present invention, the 25 hydroxy vitamin D specifically includes 25 hydroxy vitamin D ₂ And 25 hydroxy vitamin D ₃ 。

In the present invention, the 25 hydroxy vitamin D sample preferably comprises human serum or plasma.

In the present invention, the alkaline phosphatase-labeled 25-hydroxyvitamin D antibody comprises 25-hydroxyvitamin D ₂ Antibodies and 25 hydroxy vitamin D ₃ An antibody.

In the present invention, the dissociation solution is incubated with the sample and alkaline phosphatase-labeled 25-hydroxyvitamin D antibody; the volume ratio of the dissociation liquid to the 25 hydroxy vitamin D sample and the alkaline phosphatase marked 25 hydroxy vitamin D antibody is 1 (0.2-1): 1-3, more preferably 1:0.33:1.67. in the present invention, the volume of the 25 hydroxy vitamin D sample is preferably 5 to 50. Mu.L, more preferably 5 to 20. Mu.L, and most preferably 10. Mu.L.

In the present invention, the incubation time is preferably 1 to 5min, more preferably 3 to 5min, and most preferably 5min.

Adding 25 hydroxy vitamin D-biotin reagent R3 and a magnetic separation reagent into the incubated sample, and continuing to incubate at 37 ℃ for 5min;

washing to remove unbound antibodies and impurities;

adding chemiluminescent substrate liquid, and measuring relative luminous intensity RLU after ALP catalyzes the substrate to emit light;

Wherein, the 25 hydroxy vitamin D antibody is coupled with alkaline phosphatase as a common coupling process for chemiluminescent platforms. The magnetic separation reagents are commercial products.

Example 4

The magnetic particle chemiluminescence detection reagent of the 25 hydroxy vitamin D dissociation solution prepared in example 3 is used for detecting the 25 hydroxy vitamin D content of the human body, and the detection method is as follows:

(1) First, 10. Mu.L of the calibrator series of example 3 (concentrations 0, 15, 30, 50, 90, 120ng/mL, respectively) was added to the reaction tube with 30. Mu.L of the dissociation solution R1 of example 2 and 50. Mu.L of the reagent R2 of example 3, and incubated for 5min at 37℃with mixing;

(2) Sequentially adding the reagent series, 50 mu L of the reagent R3 of the example 3 and 25 mu L of the reagent magnetic separation reagent into a reaction tube, and mixing and incubating for 5min at 37 ℃;

(3) Washing with a washing liquid 3 times to remove unbound antibodies and impurities;

(4) 150 μl of the luminescence substrate solution of example 3 was added, and the relative luminescence intensity (RLU) was measured by using a Lidman chemiluminescent detector after luminescence of the ALP-catalyzed substrate, to obtain a 25-hydroxy vitamin D concentration-luminescence value series.

(5) Fitting was performed according to the 25-hydroxy vitamin D concentration-luminescence value series values to obtain a standard curve of 25-hydroxy vitamin D concentration-luminescence value based on the standard, as shown in fig. 1.

(6) And calculating and measuring the concentration value of the sample to be measured according to the fitted standard curve of the concentration-luminous value of the 25-hydroxy vitamin D.

RLU is inversely proportional to the concentration of 25 hydroxy vitamin D antigen within a certain range, and the 25 hydroxy vitamin D content of the sample to be measured can be read from the standard curve by interpolation.

TABLE 3 Standard curve (example 2)

Calibrator (ng/mL)	0	15	30	50	90	120
							RLU(10000)	518.56	113.61	37.03	13.97	3.3	0.95

The dissociation liquids in comparative examples 1 and 2 were used to obtain their corresponding concentration-luminescence value graphs, as shown in fig. 2 and 3. The comparison of standard curves obtained for different concentrations of N, N-dimethylformamide (v/v) and 5-sulfosalicylic acid (w/v) in specific comparative examples 1 and 2 is as follows:

TABLE 4 Standard curves (comparative example 1N, N-dimethylformamide (v/v) content 5%, 5-sulfosalicylic acid (w/v) content 0.5%)

Calibrator (ng/mL)	0	15	30	50	90	120
							RLU(10000)	493.15	105.9	34.6	14.08	3.11	0.9

TABLE 5 Standard curves (comparative example 2N, N-dimethylformamide (v/v) content 20%, 5-sulfosalicylic acid (w/v) content 2%)

Calibrator (ng/mL)	0	15	30	50	90	120
							RLU(10000)	446.91	93.55	32.17	11.63	2.91	0.8

The dissociation liquid in comparative example 3 was used to obtain a corresponding concentration-luminescence value graph as shown in fig. 4. In specific comparative example 3, the dissociation solution R1 is 0.5M sodium hydroxide, the reagent R3 is MES buffer with ph6.0, 10% absolute ethanol as amphoteric reagent and 0.5% DTT as reducing reagent are added, and the standard curve results obtained are as follows:

table 6 Standard Curve (comparative example 3 Strong base reagent and amphoteric reagent)

Calibrator (ng/mL)	0	15	30	50	90	150
							RLU(10000)	85.36	60.17	54.92	40.16	25.61	12.84

Wherein the curve luminescence value obtained in comparative example 2 has obvious amplitude reduction, and it is presumed that the activity of alkaline phosphatase is destroyed by too high concentration of N, N-dimethylformamide, and the content of solid N, N-dimethylformamide in the dissociation liquid is not too high; too high a level of 5-sulfosalicylic acid as a surfactant also adversely affects the reactivity of the overall system. Comparative example 3 the test calibrator had a weak overall reactivity and no obvious gradient discrimination, and the sample measurements were subject to large fluctuations.

Adding 10 mu L of a sample/quality control to be detected, 30 mu L of dissociation solution R1 and 50 mu L of reagent R2 of example 2 into a reaction tube, and mixing and incubating for 5min at 37 ℃; repeating the steps (2) - (4) to determine the relative luminous intensity RLU of the sample to be detected;

and calculating the concentration value of the 25-hydroxy vitamin D corresponding to the RLU of the sample to be detected according to the standard curve of the concentration-luminous value of the 25-hydroxy vitamin D.

By adopting the detection method, the following indexes can be achieved through methodology identification data:

sensitivity: can reach 0.597ng/mL, as shown in Table 7;

TABLE 7 sensitivity

25OHD-STD-A				25OHD-STD-B
					5236644	5210575	5019643	5028417	1130654
5031725	5063759	4939072	5044442	1125874
					5142578	5170672	4998760	5066666
5164876	5096575	5128030	5097915
					5073474	5045981	5097659	4932896
RLU mean at point A	5079518
					RLU mean value at point B	1128264
Point a SD	80713
					Point A mean-2 SD	4918091

As can be seen from table 7, the point a emission value means x= 5079518, sd=80713, X-2sd= 4918091; the average value of the luminous value of the point B is 1128264. The AB point connecting line fitting equation is y= -263417x+5079518, R ² ＝1。

And substituting the luminous value of M-2SD into the equation according to the linear fitting equation of the concentration-luminous value of the A-B point, and obtaining the corresponding concentration value, namely the lowest detection limit of the kit is 0.597ng/mL.

Conclusion: the dissociation liquid test used in example 2 had a sensitivity of 0.597ng/mL, which is superior to the sensitivity of the marketed magnetic particle chemiluminescent kit (comparative example 3), which is 1.26ng/mL; the dissociation solution used in example 2 was not significantly different from the test sensitivity of comparative example 1.

Repeatability: quality control QC1 precision of 15+/-20% (ng/mL) of target concentration range is 3.35% (n=10), QC2 precision of quality control QC2 precision of 40+/-20% (ng/mL) of target concentration range is 2.20% (n=10), and precision is far lower than national requirements, which indicates that the kit has good repeatability in the experimental process, as shown in Table 8;

table 8 repeatability:

conclusion: the reproducibility of the control quality of the dissociation liquid test used in example 2 (invention) was better than that of the kit of comparative example 3, which was 4.93% and 3.58%, respectively; the dissociation solution used in example 2 has no significant difference from the test repeatability of comparative example 1.

Correlation: the detection reagents obtained by using the dissociation solutions of example 2 (invention) and comparative example 1 were used to simultaneously detect 129 samples using the magnetic particle chemiluminescence kit (comparative example 4) on the market, and correlation analysis was performed respectively: regression analysis was performed with the concentration of 25 hydroxyvitamin D measured with the reagent of the present invention as the ordinate and the result of the measurement with the kit of comparative example 4 as the abscissa, and as shown in fig. 5, the correlation equation was y= 1.0918x-0.4794, and the correlation coefficient R ² The statistical treatment results showed good correlation. And the correlation analysis result obtained using the dissociation liquid of comparative example 1, as shown in fig. 6, was inferior in correlation.

Table 9 clinical sample alignment correlation (example 2, comparative example 1 and comparative example 4 kit):

conclusion: the dissociation solution in this example 2 was simultaneously detected on 129 samples using the kit of comparative example 4, the concentration of 25 hydroxyvitamin D measured using the reagent of the present invention was taken as the ordinate, the regression analysis was performed using the result of the determination using the immunoassay kit of the michaeli chemiluminescence method as the abscissa, the correlation equation was y= 1.0918x-0.4794, and the correlation coefficient R ² The statistical treatment results showed slightly better correlation.

In contrast, the dissociation solution in comparative example 1 and the concentration of the test sample of the Michael kit are subjected to regression analysis, and the correlation equation is y=0.8628x+5.2769, correlation coefficient R ² The statistical treatment results show that the correlation is slightly worse, and partial sample dissociation is incomplete, and the contents of N, N-dimethylformamide and 5-sulfosalicylic acid are not optimal.

Alternatively, 50 samples are used for carrying out correlation analysis on the magnetic particle chemiluminescence detection result and the measurement result of the liquid chromatography-mass spectrometry/mass spectrometry by adopting a linear regression equation, and the result is shown in fig. 7:

table 10 magnetic particle chemiluminescence and liquid chromatography-mass spectrometry/mass spectrometry results were compared.

Conclusion: two methodological correlation coefficients R ² The correlation is good, and the 25 hydroxy vitamin D dissociation liquid provided by the invention is matched with the magnetic particle chemiluminescent reagent, so that the magnetic particle chemiluminescent reagent has good effectiveness.

Stability: the stability experiments of the kit in the embodiment 3 at 2-8 ℃ and 37 ℃ are respectively carried out, the kit is placed at 2-8 ℃ for 12 months and at 37 ℃ for 7 days, the calibration of the calibrator is normal, the quality control product measured value is in the target value range, the lowest detection limit is lower than 1ng/mL, the repeatability is lower than +/-10%, and the correlation of the test sample is good. Thus, the effective period of the kit can reach 12 months.

According to various analysis performance indexes and correlation results, the contents of the protein precipitant 5-sulfosalicylic acid and N, N-dimethylformamide are preferably 1% and 10% respectively, and the overall performance of the kit is best. Compared with the commercial product (total detection time of 27 min), the kit with the proportion of 3 (total detection time of 30 min) and the kit with the comparison example of 4 (total detection time of more than 37.5 min), the magnetic particle chemiluminescence reagent matched with the 25 hydroxy vitamin D dissociation liquid provided by the invention can effectively shorten the detection time (total detection time of less than 15 min), 25 hydroxy vitamin D in a sample can be dissociated completely, the effect of full dissociation can be achieved for different storage conditions and different time nodes, the sensitivity and repeatability are better, and the defects of low liquid-mass detection flux and longer detection time of the existing magnetic particle chemiluminescence product are overcome.

The invention provides an application of the dissociation liquid in a 25-hydroxy vitamin D serum or plasma sample magnetic particle chemiluminescence platform. In the present invention, a serum or plasma sample is subjected to a fully automated immunoassay according to the methods of use described above. The foregoing description of the technical solution of the present invention will be clearly and completely described in connection with the embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims

1. A 25 hydroxy vitamin D dissociation solution, which is characterized by comprising a buffer solution, a protein precipitant, N-dimethylformamide and a sterilizing agent;

2. The dissociation liquid of claim 1, wherein said buffer is citrate and the concentration of said citrate in the dissociation liquid is between 10 and 200mM; the protein precipitant is 5-sulfosalicylic acid, and the mass concentration of the 5-sulfosalicylic acid in the dissociation liquid is 0.5-2 wt%; the volume concentration of the N, N-dimethylformamide is 5% -20%; the sterilizing agent is MIT (methyl isothiazolinone), and the volume concentration of the sterilizing agent in the dissociation liquid is 0.05% -0.2%.

3. The dissociation liquid of claim 1, wherein the pH of the dissociation liquid is 3 to 5.

4.A method of using the dissociation liquid according to any one of claims 1 to 3, comprising the steps of: incubating the dissociation solution with a 25 hydroxyvitamin D sample and an alkaline phosphatase-labeled 25 hydroxyvitamin D antibody;

the volume ratio of the dissociation solution to the 25 hydroxy vitamin D sample and the alkaline phosphatase marked 25 hydroxy vitamin D antibody is 1 (0.2-1) (1-3); the volume of the 25-hydroxy vitamin D sample is 5-50 mu L, and the volume of the alkaline phosphatase-labeled 25-hydroxy vitamin D antibody is 30-90 mu L.

5. The method of claim 4, wherein the co-incubation time is 1-5 min; after co-incubation, 25 hydroxy vitamin D-biotin reagent R3 and a magnetic separation reagent are added, and incubation is continued for 5min at 37 ℃;

washing to remove unbound antibodies and impurities;

the relative luminescence intensity RLU is inversely proportional to the 25 hydroxy vitamin D antigen concentration within a certain range, and the 25 hydroxy vitamin D content of the sample to be measured is read from the standard curve by interpolation.

6. Use of a dissociation liquid according to any of claims 1 to 3 in a magnetic particle chemiluminescent platform for 25 hydroxy vitamin D samples.

7. The use according to claim 6, wherein the sensitivity is determined for the content of 25 hydroxy vitamin D in humans: the minimum detection amount is less than 1.00ng/mL;

repeatability: quality control QC1 precision is 3.35% (n=10, the number of repetitions), quality control QC2 precision is 2.20% (n=10, the number of repetitions);

stability: the effective period of the kit can be as long as 12 months.