CN116642970A

CN116642970A - Sample pretreatment method for simultaneously detecting 6 drug concentrations in blood

Info

Publication number: CN116642970A
Application number: CN202310476812.2A
Authority: CN
Inventors: 张�杰; 贾永娟; 刘春冉; 倪君君
Original assignee: Beijing Harmony Health Medical Diagnostics Co ltd
Current assignee: Beijing Harmony Health Medical Diagnostics Co ltd
Priority date: 2023-04-27
Filing date: 2023-04-27
Publication date: 2023-08-25

Abstract

The present disclosure relates to a sample pretreatment method for simultaneously detecting 6 drug concentrations in blood, the sample pretreatment method comprising: mixing the blood sample to be treated, an internal standard substance and a protein precipitant, and taking clear liquid to obtain a sample to be detected; wherein the 6 drugs are carbidopa, dopamine, memantine, rivastigmine, levodopa and 3-methoxy dopa; the protein precipitant is an aqueous solution containing an acid compound selected from perchloric acid, sulfosalicylic acid or trichloroacetic acid. The method uses the specific acid compound as the protein precipitant to perform sample pretreatment on the blood sample, can meet the requirement of simultaneously detecting the concentration of 6 drugs in the blood, and particularly for dopamine, memantine and the like, and cannot cause the reduction of the accuracy of detection results due to incomplete sample pretreatment.

Description

Sample pretreatment method for simultaneously detecting 6 drug concentrations in blood

Technical Field

The disclosure relates to the technical field of instrument detection, and in particular relates to a sample pretreatment method for simultaneously detecting the concentration of 6 drugs in blood.

Background

Parkinson's disease, also known as paralysis agitans, is a chronic progressive disease of the extrapyramidal dysfunction of the central nervous system. The common drugs include carbidopa, levodopa, dopamine, rivastigmine, memantine, etc. The detection of the concentration of the above-mentioned drugs in blood is an important study for development of bioequivalence with the original drugs.

Wherein, the combined treatment of carbidopa and levodopa can reduce the adverse reaction of peripheral cardiovascular of the levodopa. Carbidopa is a peripheral decarboxylase inhibitor, is not easy to enter the nerve center, can inhibit the conversion of peripheral levodopa into dopamine, and causes the gradual increase of levodopa entering the nerve center. The composition can be used in combination with levodopa to reduce adverse reaction of levodopa to peripheral cardiovascular, and can be used for treating Parkinson disease caused by various reasons, and the 3-methoxy dopa of levodopa metabolite has strong activity.

Dopamine is a cerebral endocrine, is the most abundant catecholamine neurotransmitter in the brain, can regulate multiple physiological functions of the central nervous system, and can be related to parkinsonism, schizophrenia, attention deficit hyperactivity syndrome, occurrence of pituitary tumors and the like. The second generation central AChE inhibitor (acetylcholinesterase inhibitor) of rivastigmine has selective inhibition effect on AChE of cerebral cortex and Hippocampus, has almost no effect on AChE of striatum and heart, and can slow down formation of amyloid precursor (APP). Rapidly absorbed by oral administration, and reaches C in about 1h _max The binding rate of the plasma protein is about 40%, and the plasma protein is clinically used for treating light and moderate AD (Alzheimer disease) through the blood brain barrier, improving cognitive dysfunction and improving memory, attention and azimuth sense. Memantine acts primarily on the glutamate neurotransmitter system in the brain, reducing background noise by acting with NMDA receptors, restoring glutamine signaling to normal physiological states.

Currently, liquid chromatography detection, liquid chromatography-mass spectrometry detection, electrochemical detection, or the like is generally adopted for blood concentration detection. Before testing a blood sample, a sample pretreatment is required for the blood or plasma/serum sample, and at present, the common method for pretreatment of the blood sample mainly comprises the following steps: organic solvent extraction, solid phase extraction and a combination thereof. However, if the concentration of multiple drugs in blood needs to be detected simultaneously, the polarity difference between different samples is large, so that the sample pretreatment of multiple drugs under the same condition may not be realized, and the requirement of detecting the concentration of multiple drugs at the same time may not be met.

Accordingly, it is desirable to provide a sample pretreatment method that enables simultaneous detection of multiple drug concentrations in blood for subsequent sample detection.

Disclosure of Invention

In order to solve the technical problems, the present disclosure provides a sample pretreatment method for simultaneously detecting the concentrations of 6 drugs in blood. The sample pretreatment method provided by the disclosure can realize pretreatment of the blood sample under the unified treatment condition, and the pretreatment method is simple and easy to implement.

In a first aspect, the present disclosure provides a sample pretreatment method for simultaneously detecting 6 drug concentrations in blood, the sample pretreatment method comprising:

mixing the blood sample to be treated, an internal standard substance and a protein precipitant, and taking clear liquid to obtain a sample to be detected;

wherein the 6 drugs are carbidopa, dopamine, memantine, rivastigmine, levodopa and 3-methoxy dopa; the protein precipitant is an aqueous solution containing an acid compound selected from perchloric acid, sulfosalicylic acid or trichloroacetic acid.

Compared with the prior art, the method has the advantages that the pretreatment of the blood samples such as dopamine, memantine and the like can be finished only by carrying out derivatization and the like in advance. The method uses the acid compound (perchloric acid, sulfosalicylic acid or trichloroacetic acid) as a protein precipitator to carry out sample pretreatment on the blood sample, can meet the requirement of simultaneously detecting the concentration of 6 medicaments in blood, and particularly can not cause the decline of the accuracy of detection results due to 'incomplete' sample pretreatment for dopamine, memantine and the like. The sample pretreatment method provided by the disclosure is simple and easy to implement, and is matched with the subsequent detection conditions, so that the recovery rate is high, the matrix effect is small, and the accuracy of the detection result is high.

The sample pretreatment method provided by the disclosure can realize simultaneous treatment of blood samples to be detected with 6 drug concentrations, and finally detect detection results of 6 substances by one needle, has short analysis time, can greatly improve detection efficiency and reduce the difficulty of sample pretreatment, so that the sample pretreatment method provided by the disclosure can be suitable for pretreatment of high-flux samples.

The sample to be detected obtained by the sample pretreatment method provided by the disclosure can be subjected to subsequent detection by utilizing a liquid chromatography or liquid chromatography-mass spectrometry combination method, the subsequent detection method is not limited, and any detection method can be applied.

As a preferred embodiment of the present disclosure, the concentration of the acid compound in the protein precipitant is 5 to 10%, for example, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, etc.

In the protein precipitant provided by the disclosure, if the concentration of the acid compound is too low, the protein precipitation effect cannot be achieved, and the impurity content in the sample to be detected obtained through treatment may be high, so that the accuracy, precision and the like of a subsequent detection result are affected. If the concentration of the acid compound is too high, intolerance to the column and instrument tubing may result.

As a preferred technical scheme of the present disclosure, the protein precipitant further contains sodium metabisulfite.

In practical application, the stability of levodopa, dopamine, rivastigmine and carbidopa in blood samples (blood plasma/serum) is poor, and in the sample pretreatment method provided by the disclosure, sodium metabisulfite is added into a protein precipitant, so that the stability of a medicament in a sample can be improved, the medicament can be stored for a certain time at normal temperature, and the sample transportation requirement and the transportation cost can be reduced.

If the blood sample to be detected is collected and processed on site for detection, the aqueous solution only containing the acid compound is used as a protein precipitator, so that the simultaneous detection of 6 substances in the blood can be realized, and the accuracy of the detection result is higher.

As a preferred embodiment of the present disclosure, in the protein precipitant, the concentration of sodium metabisulfite is 5-15%, for example, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, etc.

In the protein precipitant provided by the disclosure, if the content of sodium metabisulfite is too low, the stability cannot be better achieved; if the sodium metabisulfite content is too high, there may be the disadvantage of contaminating the mass spectrum.

As a preferred embodiment of the present disclosure, the volume ratio of the blood sample to be treated to the protein precipitant is 1 (1-5), e.g., 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, etc.

In the method, the volume ratio of the blood sample to be treated and the protein precipitant can ensure the treatment effect of pretreatment in the range, remove impurities as much as possible and make the sample more stable; if the amount of the protein precipitant is too low, incomplete precipitation of impurities may be caused, and if the amount of the protein precipitant is too high, the blood sample to be processed may be diluted too much, i.e. the concentration of the analyte in the sample to be detected is too low, which may cause difficulty in subsequent detection.

As a preferred embodiment of the present disclosure, the sample pretreatment method includes:

mixing a blood sample to be treated with a protein precipitant, preserving for later use, mixing the mixed solution with an internal standard working solution, centrifuging, and taking a supernatant as a sample to be tested before testing;

wherein the internal standard working solution is a solution containing internal standard substances of the 6 medicines.

The method can ensure the stability of the to-be-detected object in the sample to a great extent, ensure that the to-be-detected sample can be stored for 24 hours at normal temperature and 48 hours at 4 ℃, and greatly reduce the sample transportation requirement and the transportation cost when the to-be-detected object is detected by adding the protein precipitant (also called a stabilizer) in a short time, then preserving, and the like.

As a preferred embodiment of the present disclosure, the blood sample to be treated is plasma or serum.

As a preferred technical solution of the present disclosure, the volume ratio of the blood sample to be treated and the internal standard working solution is (5-10): 1, for example, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, etc.

As a preferred technical scheme of the disclosure, the internal standard working solution is diluted by an internal standard stock solution by using a diluent, and the internal standard stock solution is obtained by respectively dissolving internal standard substances of the 6 medicines by using a solvent.

The preparation method of the internal standard working solution is a preparation method commonly used in the field at present, so the method is not limited by excessive internal standard working solution, and any preparation method capable of obtaining the internal standard working solution can be used for disclosure.

As a preferred embodiment of the present disclosure, the diluent is an aqueous methanol solution with a concentration of 65-75%, for example, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, etc.

As a preferred technical scheme of the disclosure, the internal standard substances of the 6 medicines are carbidopa-d 3, dopamine-d 3, memantine-d 6, carbidopa-d 6, levodopa-d 3 and 3-methoxy dopa-d 3 respectively.

As a preferred technical scheme of the present disclosure, in the internal standard working solution, the concentration of carbidopa-d 3 is 0.8 mug/mL, the concentration of dopamine-d 3 is 0.2 mug/mL, the concentration of memantine-d 6 is 0.4 mug/mL, the concentration of carbidopa-d 6 is 0.2 mug/mL, the concentration of levodopa-d 3 is 10.0 mug/mL, and the concentration of 3-methoxy dopa-d 3 is 30.0 mug/mL.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:

(1) The method uses the specific acid compound as the protein precipitant to perform sample pretreatment on the blood sample, can meet the requirement of simultaneously detecting the concentration of 6 medicaments in the blood, and particularly for dopamine, memantine and the like, the quantitative limit and the detection limit of a detection result are higher because of 'incomplete' sample pretreatment, and the detection requirement cannot be met;

(2) The sample pretreatment method provided by the disclosure is simple and easy to implement, and is matched with the subsequent detection conditions, so that the recovery rate is high, the matrix effect is small, and the accuracy of the detection result is high.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments of the present disclosure or the solutions in the prior art, the drawings that are required for the description of the embodiments or the prior art will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

FIG. 1 is a chromatogram of carbidopa, dopamine, memantine, rivastigmine, levodopa and its metabolite 3-methoxydopa in the standard solution for performance testing of the present disclosure;

FIG. 2 is a chromatogram of carbidopa, dopamine, memantine, rivastigmine, levodopa and its metabolite 3-methoxydopa in a plasma sample according to example 2 of the present disclosure;

wherein, the chromatographic peaks in fig. 1 and 2 are in turn from left to right: levodopa, dopamine, carbidopa, 3-methoxydopa, memantine and rivastigmine;

FIG. 3 is a chromatogram obtained using the chromatographic column of example 3;

FIG. 4 is a chromatogram obtained after providing a sample processing method to be tested using comparative example 1;

fig. 5 is a chromatogram obtained after providing a sample processing method to be tested using comparative example 2.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, a further description of aspects of the present disclosure will be provided below. It should be noted that, without conflict, the embodiments of the present disclosure and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced otherwise than as described herein; it will be apparent that the embodiments in the specification are only some, but not all, embodiments of the disclosure.

Example 1

The embodiment provides a preparation method of an internal standard working solution.

(1) Preparing internal standard stock solution

L-dopa-d 3 standard with the specification of 2.00mg is added with 1mL of methanol: water=1:1 solution, 40 mu L of formic acid is added, 960 mu L of methanol: water=7:3 solution is added, the purity is 98.7%, and stock solution with the concentration of 987 mu g/mL is obtained;

the specification of the carbidopa-d 3 standard substance is 1.00mg, 0.5mL of methanol-water=1:1 solution is added, 20 mu L of formic acid is added, and 480 mu L of methanol-water=7:3 solution is added to obtain a stock solution with the concentration of 991 mu g/mL;

dopamine-d 3 standard specification is 2.00mg, 1mL of methanol is added, and 1mL of methanol-water=7:3 solution is added to obtain a stock solution with the concentration of 803.24 mug/mL;

memantine-d 6 standard with specification of 2.00mg, adding 1mL of methanol, and then adding 1mL of methanol: water=7:3 solution to obtain a stock solution with concentration of 815.73 μg/mL;

the specification of the rivastigmine-d 6 standard is 1.00mg, 0.5mL of methanol is added, and then 0.5mL of methanol-water=7:3 solution is added to obtain a stock solution with the concentration of 618.05 mug/mL;

3-Methoxydopa-d 3 standard specification 1.00mg, 0.5mL of methanol was added, and 0.5mL of methanol: water=7:3 solution was added to give a stock solution having a concentration of 894. Mu.g/mL.

(2) Preparing an internal standard intermediate liquid by using a diluent of methanol: water=7:3, mixing the internal standard stock solution and the internal standard intermediate liquid, and diluting by using the diluent of methanol: water=7:3 to obtain an internal standard working solution, wherein the specific details are shown in table 1:

TABLE 1

Example 2

The embodiment provides a sample pretreatment method of a blood sample to be tested, which comprises the following steps:

(1) Venous blood sampling, placing in a purple cap tube/EDTA anticoagulation tube, centrifuging at 3500r/min for 10min, and separating plasma to obtain EDTA plasma as a blood sample to be tested;

(2) Mixing 1mL of blood sample to be measured with a protein precipitant 1:1, wherein the protein precipitant is an aqueous solution containing 6% perchloric acid and 10% sodium metabisulfite, and the obtained mixed solution is refrigerated at 4 ℃ and stored for standby in dark places;

(3) Before detection, transferring 10 mu L of internal standard working solution to a 1.5mL plastic centrifuge tube by using a pipetting gun, adding 200 mu L of the mixed solution obtained in the step (2), uniformly mixing by vortex at 2000r/min for 5min, centrifuging at 14000r/min for 10min, and taking 100 mu L of supernatant as a sample to be detected.

Examples 3 to 4

The embodiment provides a sample pretreatment method of a blood sample to be tested.

The difference from example 2 is that in this example perchloric acid is replaced by sulfosalicylic acid (example 3), trichloroacetic acid (example 4).

Examples 5 to 6

The embodiment provides a sample processing method and a detection method.

The difference from example 3 is that in this example, the protein precipitant in step (2) is: 5% perchloric acid+15% sodium metabisulfite (example 5), 10% perchloric acid+5% sodium metabisulfite (example 6).

Example 7

The difference from example 2 is that in this example, the perchloric acid concentration in the protein precipitant is 3%.

Example 8

The difference from example 2 is that in this example the sodium metabisulfite concentration in the protein precipitant is 1%.

Comparative example 1

The comparative example provides a sample pretreatment method for a blood sample to be tested.

The difference from example 2 is that the protein precipitant in this example is acetonitrile.

Comparative example 2

The difference from example 2 is that the protein precipitant in this example is hydrofluoric acid.

Performance testing

The liquid chromatography-mass spectrometry is used for detecting the samples to be detected, which are obtained by the sample pretreatment methods provided in the examples and the comparative examples, and the detection method is as follows:

A. preparing 6 kinds of medicine standard stock solution

Accurately weighing 2.50mg of levodopa standard substance in a 2mL freezing tube, adding 2mL of methanol/water=7:3 solution for dissolution, adding 40 mu L of formic acid with purity of 99.5%, and uniformly mixing to obtain a stock solution with concentration of 1221.31 mu g/mL;

3.750mg of 3-methoxy dopa standard substance is precisely weighed by a balance and placed in a 2mL freezing tube, 0.5mL of methanol is added for dissolution, 1mL of methanol is added for water=1:1 solution, the purity is 100.0%, and stock solution with the concentration of 2500.00 mug/mL is obtained after uniform mixing;

3.62mg of carbidopa standard substance is precisely weighed by a balance and placed in a 2mL freezing tube, 2mL of methanol-water=7:3 solution is added for dissolution, 40 mu L of formic acid is added, and the mixture is uniformly mixed to obtain a stock solution with the concentration of 1627.68 mu g/mL;

accurately weighing 3.147mg of memantine standard substance (memantine hydrochloride) in a 2mL freezing tube by a balance, adding 1mL of methanol for dissolution, adding 0.5mL of methanol-water=7:3 solution with the purity of 100.0%, and uniformly mixing to obtain a stock solution with the concentration of 1727.92 mug/mL;

accurately weighing 1.85mg of dopamine standard substance (dopamine hydrochloride) in a 2mL freezing tube, adding 1.5mL of methanol for dissolution, and mixing uniformly to obtain a stock solution with the concentration of 992.13 mug/mL, wherein the purity is 100.0%;

2.00mg of rivastigmine standard (rivastigmine) is precisely weighed by a balance into a 2mL freezing tube, 1.5mL of methanol-water=7:3 solution with purity of 100.0% is added, and the mixture is uniformly mixed to obtain a stock solution with concentration of 833.57 mug/mL.

(2) Standard intermediate solutions were prepared with 10% sodium metabisulfite in methanol water=1:9 diluent, mixed and diluted with 10% sodium metabisulfite in methanol water=1:9 diluent to give 7 grade concentrations of standard working solution, see table 2 for details:

TABLE 2

B. Preparing standard solution

a. The internal standard working solution and the standard working solution are placed at room temperature for 30min to be balanced to the room temperature;

b. 9 1.5mL centrifuge tubes, numbered L8-L1 and blank, were taken, 10. Mu.L of the internal standard working solution was aspirated by a micropipette (measuring range: 0.5-10. Mu.L) and added to the centrifuge tube numbered L8-L1, and 10. Mu.L of methanol: water=7:3 diluent was added to the blank centrifuge tube.

c. 10 mu L of each standard working solution is sucked by a micropipette (measuring range: 0.5-10 mu L), added into a centrifuge tube with corresponding number, 10 mu L of methanol containing 10% sodium metabisulfite and diluent with water ratio of 1:9 are added into a centrifuge tube with blank number, 90 mu L of pure water and 100 mu L of aqueous solution of 6% acid compound (corresponding to the use in pretreatment of a sample) are accurately sucked into each centrifuge tube, and 2000r/min are uniformly mixed for 1min, so that 8 standard solutions with different concentrations are obtained.

C. Establishing a standard curve and detecting a sample to be detected

Detecting the standard solution by using a high performance liquid chromatography mass spectrometer, and respectively establishing standard curves of 6 medicaments;

when a standard curve is established, taking the ratio of the peak area of the target object to the corresponding internal standard peak area as Y, and taking the ratio of the concentration of the target object to the corresponding internal standard concentration as X;

and detecting the sample to be detected by using a high performance liquid chromatography mass spectrometer, and determining the concentration of 6 medicaments in the sample to be detected by using the established standard curve.

The detection parameters are as follows:

A. the detecting instrument is Agilent MS6470A detector

The chromatographic column used for the chromatography was Agilent Poroshell EC-C18, 3.0X100 mm, 2.7. Mu.m;

mobile phase: phase A is 5mmol/L ammonium formate aqueous solution containing 0.2% formic acid, and phase B is acetonitrile; the analytical chromatographic column adopts a gradient elution mode, the flow rate is 0.4mL/min, the column temperature is 40 ℃, and the sample injection amount is 5 mu L; analysis time 5.5min, gradient elution conditions are shown in Table 3:

TABLE 3 Table 3

For mass spectrometry conditions, electrospray ion source (ESI), positive ion mode, multiple Reaction Monitoring (MRM) were used, specific parameters are shown in table 4, and ion pair parameters are shown in table 5.

TABLE 4 Table 4

TABLE 5

(1) Examples 2-8 and comparative examples 1-2 were tested using the above liquid chromatography conditions and the chromatographic results were as follows:

FIG. 1 is a chromatogram of carbidopa, dopamine, memantine, rivastigmine, levodopa and its metabolite 3-methoxydopa in the standard solution for performance testing of the present disclosure; fig. 2 is a chromatogram of carbidopa, dopamine, memantine, carbidopa, levodopa and its metabolite 3-methoxydopa in a plasma sample according to example 2 of the present disclosure, fig. 3 is a chromatogram obtained by using a stabilizer of example 3, and fig. 4-6 are similar to fig. 3, and it can be seen from fig. 1-3 that a chromatogram baseline of a sample to be measured obtained by using a stabilizer (precipitant) according to the present disclosure is stable, and no impurity peak exists, that is, it is shown that the sample pretreatment method provided by the present disclosure has good impurity removal effect, good stabilizing effect on carbidopa and the like, and small matrix effect, and can meet the quantitative requirement while accurately quantifying.

Fig. 4 is a liquid chromatogram obtained by using the method for processing the sample to be tested in comparative example 1, and as can be seen from comparison of fig. 2 and fig. 4, the pretreatment of the sample by using acetonitrile has obvious solvent effect, and the matrix effect of carbidopa, dopamine and levodopa is extremely strong, so that the quantitative limit cannot meet the detection requirement. Fig. 5 is a chromatogram obtained using the stabilizer of comparative example 2, and as can be seen from fig. 5, similar effects can be achieved using hydrofluoric acid as the stabilizer used in the present disclosure, but hydrofluoric acid is volatile, has a strong pungent odor and has extremely strong corrosiveness, and is extremely harmful to human body.

(2) The analytical methods provided in examples 2 to 8 of the present disclosure and comparative example 1 were subjected to linear analysis while obtaining detection limit and quantitative limit results as shown in tables 6 to 7:

TABLE 6

TABLE 7

(3) After the labeled sample was placed at 4 ℃ for 24 hours, the labeled sample was tested to determine the stability of carbidopa placement, and the results are shown in table 8:

TABLE 8

As can be seen from tables 6 to 7, the sample pretreatment methods provided in examples 2 to 6 have lower detection limits and lower quantification limits, and can well meet application requirements. As is clear from Table 7-8, when the concentration of the acid-based compound and/or sodium metabisulfite in the protein precipitant is too low, the effect of removing impurities is not good, or the stability of carbidopa or the like is lowered, resulting in inaccurate quantification, high limit of quantification and high limit of detection. The substrate effect of comparative example 1 is extremely strong, and thus the detection is greatly affected, and the quantitative limit of the substrate is not satisfied at all.

It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is merely a specific embodiment of the disclosure to enable one skilled in the art to understand or practice the disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown and described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sample pretreatment method for simultaneously detecting 6 drug concentrations in blood, the sample pretreatment method comprising:

2. The method for sample pretreatment according to claim 1, wherein the concentration of the acid compound in the protein precipitant is 5 to 10%.

3. The method for sample pretreatment according to claim 1 or 2, wherein the protein precipitant further comprises sodium metabisulfite.

4. A sample pretreatment method according to any one of claims 1 to 3, wherein the concentration of sodium metabisulfite in the protein precipitant is 5 to 15%.

5. The method for pretreatment of a sample according to any of claims 1 to 4, wherein the volume ratio of the blood sample to be treated to the protein precipitant is 1 (1 to 5).

6. The sample pretreatment method according to any one of claims 1 to 5, wherein the sample pretreatment method comprises:

wherein the internal standard working solution is a solution containing internal standard substances of the 6 medicines;

preferably, the blood sample to be treated is plasma or serum.

7. The method according to claim 6, wherein the volume ratio of the blood sample to be processed to the internal standard working fluid is (5-10): 1.

8. The method according to claim 6 or 7, wherein the internal standard working solution is diluted with a diluent from an internal standard stock solution obtained by dissolving the internal standard of each of the 6 drugs with a solvent.

9. The method for pretreatment of a sample according to claim 8, wherein the diluent is an aqueous methanol solution having a concentration of 65 to 75%.

10. The method of any one of claims 1-9, wherein the internal standard of the 6 drugs is carbidopa-d 3, dopamine-d 3, memantine-d 6, carbidopa-d 6, levodopa-d 3, and 3-methoxydopa-d 3, respectively.