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YY/T 0616.1-2016 (YY/T0616.1-2016)

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YY/T 0616.1-2016: PDF in English (YYT 0616.1-2016)
YY/T 0616.1-2016
YY
PHARMACEUTICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 11.040.01
C 30
Replacing YY/T 0616.1-2007
Medical gloves for single use - Part 1.
Requirements and testing for biological evaluation
ISSUED ON. JANUARY 26, 2016
IMPLEMENTED ON. JANUARY 01, 2017
Issued by. China Food and Drug Administration
Table of Contents
Foreword ... 3
Introduction ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Requirements... 7
5 Test methods ... 9
Annex A (normative) Method for determining water-soluble proteins of natural
rubber gloves by improved Lowry analytical method ... 11
Annex B (informative) Immunoassay method for natural rubber latex allergens
... 23
Annex C (informative) Determination of amino acids (AAA) by high performance
liquid chromatography (HPLC) ... 28
Bibliography ... 37
Foreword
YY/T 0616 “Medical gloves for single use” consists of the following parts.
- Part 1. Requirements and testing for biological evaluation;
- Part 2. Requirements and testing for shelf life determination.
This Part is Part 1 of YY/T0616.
This Part was drafted in accordance with the rules given in GB/T 1.1-2009.
This Part replaces YY/T 0616-2007 “Medical gloves for single use -
Requirements and testing for biological evaluation”. Compared with YY/T 0616-
2007, the main technical changes are as follows.
- MODIFY the standard name;
- MODIFY and SUPPLEMENT “3 Terms and definitions”;
- ADD “4.4 Powder, 4.5 Leachable proteins and 4.6 Labeling";
- MODIFY Annex B Immunoassay method for natural rubber latex allergens;
- MODIFY Annex C Determination of amino acids (AAA) by high performance
liquid chromatography (HPLC);
- DELETE Annex D Terms.
Attention is drawn to the possibility that some of the elements of this document
may be the subject of patent rights. The drafting authority of this document shall
not be held responsible for identifying any or all such patent rights.
This Part is under the jurisdiction of China Food and Drug Administration Jinan
Medical Device Quality Supervision and Inspection Center.
Drafting organizations of this Part. Shandong Medical Device Quality Inspection
Center, Beijing Institute of Medical Device Testing, Jiangsu Institute of Medical
Device Testing.
Main drafters of this Part. Hao Shubin, Liu Bin, Liu Xiaoshuai, Huang Yongfu,
Lin Hongsai, Gao Jingxian, Jin Meng.
The historical edition of the standard replaced by this Part is as follows.
- YY/T 0616-2007.
Introduction
In recent years, it is often reported that latex products cause adverse reactions
to medical personnel and patients due to the presence of latex proteins. The
adverse reactions due to residues such as chemicals, lubricants, sterilized
residues (ethylene oxide) and pyrogens are also described in scientific
bibliographies. Among them, the most commonly reported are adverse
reactions caused by natural rubber latex gloves, but gloves made of other
polymers can also cause some adverse reactions.
GB/T 16886 series of standards specifies the requirements and test methods
for biological evaluation of medical devices. However, adverse reactions (such
as immediate hypersensitivity reactions) caused by the use of medical gloves
are not involved. These adverse reactions are mainly caused by the specific
allergens present in the gloves. The factors for these reaction risks are.
a) the time and frequency of skin contact with the gloves;
b) the mucous membranes and the skin (especially when incomplete) are in
direct contact with allergens [Translator note. There is another nick-name
in Chinese] and inhalation particles;
c) how closely the gloves are applied to the skin during use.
FDA believes that the powder in gloves is also a source of danger, which may
lead to foreign body reaction and granuloma formation, and may also lead to
irritant dermatitis, type IV allergy, etc. It may be used as an airborne carrier for
natural latex to cause users allergy.
This Part gives the requirements and test methods for the biological safety
evaluation of medical gloves, which is taken as a part of the risk analysis
process according to YY/T 0316 and GB/T 16886.
Medical gloves for single use - Part 1.
Requirements and testing for biological evaluation
1 Scope
This Part of YY/T 0616 specifies the requirements for the biological safety
evaluation of medical gloves for single use, and gives the requirements for the
labeling and disclosure of information for the test methods used.
This Part applies to the biological safety evaluation of medical gloves for single
use.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 16886 (all parts) Biological evaluation of medical devices
GB/T 21869 Medical gloves - Determination of removable surface powder
YY/T 0316 Medical devices - Application of risk management to medical
devices (YY/T 0316-2008, ISO 14971.2007, IDT)
YY/T 0466.1 Medical devices - Symbols to be used with medical device
labels labelling and information to be supplied - Part 1. General requirements
(YY/T 0466.1-2009, ISO 15223-1.2007, IDT)
Pharmacopoeia of the People’s Republic of China (2010 edition)
ISO 7000 Graphical symbols for use on equipment - Index and synopsis
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1
chemicals
Substances that are added or formed during or after any process of the
production process. These substances can be detected from the final product.
NOTE. These chemicals include lubricant, chemical coating and sterilant. Chemicals
are often used during glove processing and some of them are known to cause type IV
hypersensitivity. The type, the residual amount and the final form of presence of the
chemicals added are uncertain.
3.2
endotoxins
Lipopolysaccharide that is derived from the of the outer structure of the Gram-
negative bacterial cell membrane.
NOTE. Endotoxin is a pyrogen. Endotoxins may come from the raw material of gloves,
especially the water used in the process of production, and bacteria contamination
caused by manual processing.
3.3
powder
Under this test condition, all water-insoluble substances that can be removed
by washing with water on the glove surface.
[GB/T 21869-2008, definition 3.1]
NOTE. Including intentionally added powder and other processing aids or
unintentionally randomly present substances, these substances can easily be
separated from the surface of gloves. This Part specifies that any glove containing less
than or equal to 2 mg of powder is a powder-free glove, and a glove with more than 2
mg of powder is a powdered glove (see 4.4 for requirements).
3.4
process limit
The possible maximum value of a confirmed process.
3.5
allergenic proteins
Proteins that can cause type I allergic reactions.
3.6
leachable proteins
Water-soluble proteins and peptides with different molecular weights that can
be leached from the final product.
3.7
pyrogens
Substances that make rabbits fever. These substances may also cause the
human body to have a fever reaction and other adverse reactions.
4 Requirements
4.1 General
Medical gloves for single use shall be evaluated according to GB/T 16886.
GB/T 16886.1 describes the general principle of biological evaluation of
medical devices and is used to select suitable tests described in other parts.
Risk management shall be conducted in accordance with YY/T 0316.
4.2 Chemicals
Gloves shall not contain or be coated with talcum powder (magnesium silicate).
If technically feasible, it shall avoid using chemicals known to have allergenicity.
Whenever feasible, it shall use GB/T 16886.17 to determine the allowable limits
for leachable residual chemicals and meet these limits. If infeasible, the residual
chemical level shall be “ALARP” [ALARP (As Low As Reasonably Practicable)
- See YY/T 0316].
If required, the manufacturer shall indicate the chemicals added during the
production process or known in the product, such as accelerators, antioxidants
and bactericides, which are known to have adverse health effects based on the
existing bibliography.
4.3 Endotoxins
If the glove is marked with “low endotoxin content”, the manufacturer shall
monitor the endotoxin contamination of the sterile glove according to the test
method specified in 5.1. For gloves with such marking, the endotoxin content
of each pair of gloves shall not exceed 20 EU.
4.4 Powder
For powder-free gloves, the total amount of residual powder determined
according to the test method of 5.2 shall not exceed 2 mg per glove. Any glove
with a powder content of more than 2 mg is powdered gloves.
4.5 Leachable proteins
The manufacturer shall monitor the process limits of soluble proteins in gloves
containing natural rubber latex according to the test method specified in 5.3. It
shall retain the test result document. It shall be able to provide test results and
test methods used as required.
The leachable protein level shall be “As Low As Reasonably Practicable”
(ALARP).
NOTE. For allergenic proteins, this Part specifies the similar methods for
measuring allergens (such as leachable proteins). There is no direct correlation
between leachable proteins and allergens. Annex B describes the under-
development quantitative testing methods for allergenic proteins.
4.6 Labelling
In addition to the relevant symbols given in YY/T 0466.1, the following
requirements apply.
a) Medical gloves containing natural rubber latex shall have at least the
following symbol on the smallest packaging unit, see Figure 1 (symbol
2725 of ISO 7000 gives the general requirements for the application of
this symbol);
Figure 1 -- Symbol for products containing natural rubber latex
b) In addition to the symbol, the label shall also include the following warning
statement or equivalent warning statement.
“(The product) contains natural rubber latex that may cause allergic
reactions (including allergic response),”;
c) The label shall prominently give a statement as to whether the glove
contains powder;
d) Sterile powdered gloves shall be marked with the following or equivalent
textual description.
“CAUTION. Surface powders shall be aseptically removed prior to surgery
to minimize the risk of adverse tissue reactions.”;
NOTE 1. This precaution may be given on the inner wrap.
e) For any medical glove containing natural rubber latex, the product label
shall not contain.
- any description that indicates relative safety, such as hypo-allergenicity
or low protein;
- any unreasonable description of the present allergens;
f) The manufacturers shall, if labeled to contain proteins, indicate the process
limits determined according to the specifications of 5.3.
NOTE 2. It is not allowed to mark that the protein content is below 50 μg/g. Due
to variability in the expected manufacturing process and inter-laboratory test
results, the nominally low protein content is considered to be unreliable.
5 Test methods
5.1 Endotoxins
Unless unresolvable interference occurs in the LAL test, the method shall be
selected, confirmed and used according to the bacterial endotoxin test specified
in the Chinese Pharmacopoeia (hereinafter referred to as the Chinese
Pharmacopoeia). The results are expressed in endotoxin units (EU) containing
in each pair of gloves.
NOTE 1. When unresolvable interference occurs in the LAL test, the bacterial
endotoxin level cannot be accurately measured.
The recommended minimum number of test gloves and the testing amount are
determined according to the batch. When the batch is less than 30 pairs, the
sampling amount is 2 pairs; when the batch is between 30 and 100 pairs, the
sampling amount is 3 pairs; when the batch is more than 100 pairs, the
sampling amount is 3 %, but the maximum sampling amount is 10 pairs for
each batch.
The outer surface of each pair of gloves, in such a way that all the outer
surfaces of the gloves are in contact with the extraction medium, is leached with
40 mL of endotoxin-free water (the bacterial endotoxin test water specified in
the Chinese Pharmacopoeia) at 37 °C to 40 °C for 40 min to 60 min. When
necessary, the leachate is centrifuged at 2000 g for 15 min to remove
particulates. After centrifugation, remove the liquid components and carry out
the endotoxin test immediately.
NOTE 2. Other existing accepted endotoxin analysis methods, only have been
confirmed and relevant to the baseline method specified in this Part, can also be used
for routine quality control.
5.2 Powder
It shall use the method described in GB/T 21869 to determine the powder
residue.
5.3 Leachable proteins
The method for determining leachable proteins shall use the improved Lowry
method given in Annex A or the method confirmed by the improved Lowry
method.
NOTE 1. The immunoassay method for proteins in Annex B has not been confirmed
by the improved Lowry method, but it can be correlated with clinical response data.
NOTE 2. Annex C gives examples of a confirmed analytical method.
Test report
The test report shall include at least the following information.
- number of this Part;
- glove type and production batch number;
- name and address of the manufacturer or the supplier and laboratory (if
different);
- test date;
- a description of the test method used;
- test results.
Annex A
(normative)
Method for determining water-soluble proteins of natural rubber gloves
by improved Lowry analytical method
A.1 Scope
This method is used to determine the mass of water-soluble proteins in medical
gloves made of natural rubber. This method has been confirmed in the synergy
test carried out between laboratories. The minimum detection limit of this
method is approximately 10 μg per gram of glove (i.e. 2 μg protein per mL of
extract), which depends on the weight of the glove.
Chemicals such as surfactants, catalysts and antioxidants that are added to
natural rubber during the production process of gloves can interfere with the
color development process. Some substances may reduce color development,
while some may increase color development. If errors occur due to interference
in the test, it may use any confirmed amino acid analytical method (such as the
method given in Annex C).
NOTE. Persons using this method shall be familiar with the general laboratory
procedures. This method does not involve safety issues. If the method of use involves
such issues, the user is responsible for establishing corresponding safety and health
regulations and ensuring that they are consistent with the requirements of the national
regulations.
A.2 Principle
Water-soluble proteins are soaked in a kind of buffer solution, then add sodium
deoxycholate, precipitate and concentrate with acid and separate from water-
soluble substances (that may interfere with the test). The precipitated protein is
re-dissolved in the base and colorimetrically quantified using the improved
Lowry method. The principle of the analysis is basing on the characteristics that
protein reacts with copper and Folin reagents in alkaline medium to form blue,
use spectrophotometer to measure in the wavelength range of 600 nm to 750
nm.
A.3 Reagents
A.3.1 General
The test water shall be double distilled water or water of the same quality, all
reagents shall be analytical regents.
A.3.2 Leaching media
A.3.2.1 N-tris-[Hydroxymethyl]-methyl-2-amioethanesulfonic acid (TES), N-
tris(hydroxymethyl)methyl 2-aminoethane sulfonic acid (TES), hemisodium-salt.
A.3.2.2 Leaching buffer solution, 0.1 mol/L. DISSOLVE 24 g of TES (A.3.2.1)
in water and DILUTE to 1 L. Any equivalent buffer system that maintains the pH
of the glove leaching solution at 7.4 ± 0.2 can be used.
NOTE. Prepare a sufficient amount of glove leaching solution (A.6.2), protein standard
solution (A.6.3.2) and blank solution.
A.3.2.3 Staining solution, sodium salt solution of bromophenol blue. DISSOLVE
100 mg of bromophenol blue with water and DILUTE to 1 L. Prepare fresh
solution every 4 weeks.
A.3.3 Lowry protein analysis kit
NOTE. The kit can be prepared using current chemicals [1], or kits can be purchased.
The method in this Part is confirming with kits1).
A.3.3.1 Reagent A, copper reagent (alkaline tartrate or copper citrate solution).
A.3.3.2 Reagent B, diluted Folin reagent.
A.3.4 Sodium hydroxide solution
[c(NaOH) = 0.1 mol//L].
A.3.5 Sodium deoxycholate (DOC)
DISSOLVE 0.15 g of sodium deoxycholate with water and DILUTE to 100 mL.
The solution could not be used over 4 weeks after it was prepared.
A.3.6 Trichloroacetic acid (TCA)
4.4 mol/L aqueous solution, which is prepared by dissolving 72 g of TCA in
water and diluting to 100 mL.
A.3.7 Phosphotungstic acid (PTA)
DISSOLVE 72 g PTA with water and DILUTE to 100 mL. The solution could not
be used over 4 weeks after it was prepared.
A.3.8 Ovalbumin
1) The Lowry Micro DC Protein Assay Kit (Cat. No. 500-0116) is available from the BioRad Laboratory at
2000 Alfred Nobel Drive, Hercules, CA 9456547, USA. This information is only for the convenience of
users of this Part and does not imply endorsement of this product.
Extracted from lyophilized eggs2), no salt.
A.4 Instruments
A.4.1 Synthetic gloves, no powder.
A.4.2 Centrifuge, with the centrifugal force can reach at least 6000 g.
A.4.3 Centrifuge tube, 30 mL or 50 mL polypropylene tube. The protein binding
capacity of the tube shall not exceed 10 μg per tube. Do not use glassware
because the surface absorbs proteins.
NOTE. A.5 gives a method to determine the protein binding capacity.
A.4.4 Filter membrane, disposable, with pore size of 0.22 μm, and the protein
binding capacity of each filter membrane does not exceed 10 μg.
NOTE. A.5 gives a method to determine the protein binding capacity.
A.4.5 Syringe, disposable, 20 mL, made of polyethylene or polypropylene
material.
A.4.6 Micro test tube, 2 mL, made of polypropylene material.
A.4.7 Quartz cuvette, with light path length of 1cm.
A.4.8 ELISA plate, 96 wells, flat bottom, made of polystyrene material, or
disposable plate well (A.4.9).
A.4.9 Disposable plate well, 1.5 mL semi-micro type, with light path of length 1
cm, made of polystyrene material.
A.4.10 Microplate reader, with wavelength range of 600 nm ~ 750 nm.
A.4.11 Spectrophotometer, with wavelength range of 230 nm ~ 750 nm.
A.4.12 Vortex mixer.
A.4.13 Micropipette, with disposable polypropylene tip.
A.4.14 Fixture, used in the leaching process to seal gloves to prevent water
leakage. It is recommended to use a foam-rubber-lined aluminum fixture (see
Figure A.1) or a 170 mm long hemodialysis plastic fixture.
2) The ovalbumin is prepared by fractionation and repeated crystallization of ammonium sulfate at pH 4.5
using ammonium sulfate. For example, Sigma A5503, chicken protein, grade V, is available from
Sigmar Chemical Co. P.O. Box 14506, St Louis, MO 63178, USA. This information is provided for
users of this section only and does not imply endorsement of this product.
Dimensions in millimeters
Key.
1 - outer glove (glove 1);
2 - inner glove (glove 2);
3 - leaching buffer solution;
4 - dyeing solution;
5 - glove fixture.
Figure A.1 -- Glove leaching
A.4.15 Oscillator.
A.5 Determination of protein binding capacity
A.5.1 General
It is recommended to use disposable polypropylene devices (polypropylene is
considered to have low protein binding capacity). Before using a new batch of
centrifuge tubes or filters, the following method shall be used to check the
protein binding capacity. The test shall be conducted within 1 d.
A.5.2 Protein adsorption capacity of centrifuge tubes
A.5.2.1 ADD 30 mL of standard solution containing 10 μg/mL ovalbumin in a
centrifuge tube (A.4.3). The standard solution is prepared by diluting the protein
stock solution (A.6.3.1) with leaching buffer solution (A.3.2.2).
A.5.2.2 PIPETTE two portions of 10 mL ovalbumin solution (A.5.2.1) into two
new centrifuge tubes, OSCILLATE the two tubes on the oscillator (A.4.15).
Make sure that all surfaces of the tubes are infiltrated with the solution. After
standing for 30 min, TRANSFER the solution in the two tubes to the other two
tubes for oscillation. REPEAT this procedure until each 10 mL of solution
infiltrates 5 tubes. STORE the remaining test solution.
A.5.2.3 USE the methods given in A.6.4 to A.6.6 to respectively determine the
protein concentration in the standard solution and the two test solutions,
MEASURE each three times.
A.5.2.4 CALCULATE the average binding capacity of ovalbumin per tube
according to equation (A.1).
where.
O - the amount of ovalbumin bound in each test tube, in micrograms (μg);
R - the average value of three measurements of the ovalbumin content in
the standard solution, in micrograms per milliliter (μg/mL);
T - the average value of the ovalbumin content in the test solution after
passing through the test tube (i.e. average value of six measurements), in
micrograms per milliliter (μg/mL).
The amount of ovalbumin bound in each test tube (O) shall be less than 10 μg.
Otherwise, these tubes are not suitable for measurement.
A.5.3 Determination of protein adsorption capacity of filters
A.5.3.1 ADD 30 mL of standard solution containing 10 μg/mL ovalbumin in a
centrifuge tube (A.4.3). The standard solution is prepared by diluting the protein
stock solution (A.6.3.1) with leaching buffer solution (A.3.2.2).
A.5.3.2 PREPARE two stacks of filter membranes (A.4.4), five pieces for each
stack. USE each stack to filter 10 mL of standard solution into a centrifuge tube
(A.4.3).
A.5.3.3 USE the methods given in A.6.4 to A.6.6 to respectively determine the
protein concentration in the standard solution and the two test solutions,
MEASURE each three times.
A.5.3.4 CALCULATE the average binding capacity of ovalbumin per tube
according to equation (A.2).
where.
O - the amount of ovalbumin bound in each test tube, in micrograms (μg);
R - the average value of three measurements of the ovalbumin content in
the standard solution, in micrograms per milliliter (μg/mL);
T - the average value of the ovalbumin content in the test solution after
passing through the test tube (i.e. average value of six measurements), in
micrograms per milliliter (μg/mL).
The amount of ovalbumin bound in each test tube (O) shall be less than 10 μg.
Otherwise, these tubes are not suitable for measurement.
A.6 Procedure
A.6.1 General
The procedure includes glove leaching, followed by purification and
concentration of the leaching solution with a factor of 5. USE the standard
protein solution concentrated in the same manner to make the calibration curve.
According to the calibration curve, determine the protein content in the leaching
solution.
The leaching procedure used is to take two gloves, one leaching the inside and
the other one leaching the outside simultaneously. This allows the leaching
volume to be as small as 25 mL, and because the leaching buffer solution only
comes in contact with the glove, protein loss caused by contact with the
container surface is avoided.
NOTE. Other leaching procedures can also be used as long as they are confirmed with
reference to this method. Interlaboratory comparison tests conducted in selected
laboratories in Europe and the United States showed that the determination result by
cutting gloves into pieces and then leaching them in TES buffer solution at pH 7.4 at
25 °C for 2 h according to ASTM D5712 is equivalent to this method.
A.6.2 Leaching procedure
A.6.2.1 Wear synthetic gloves (A.4.1) to operate glove samples for leaching.
TAKE 8 glove samples of the same size and the same batch and divide them
into 4 pairs. If the gloves are divided into right-handed and left-handed, select
4 right-handed samples, 4 left-handed samples, and divide them into two pairs
of right-handed gloves and two pairs of left-handed gloves.
First SELECT a glove form each pair of gloves, MARK at (200 ± 10) mm from
the tip of the middle finger to the wrist, WEIGH it (m1), accurate to 0.1 g. Then
INSERT the other glove in each pair of gloves into the marked glove to make it
completely fit, as shown in Figure A.1 a).
NOTE. The method of inserting one glove into the other is not very important for the
test, but its operation shall be as simple as possible. To do this, first insert a round bar
into the thumb and the little finger of the inner glove to insert them into the
corresponding fingers of the outer glove, and insert the other three fingers with the
round bar.
A.6.2.2 FILL enough staining solution (A.3.2.3) into the five fingers of the inner
glove. Between the inner and outer gloves, INJECT 25 mL of the leaching buffer
solution (A.3.2.2) at the temperature of (25 ± 5) °C. For larger gloves, the
volume of added buffer solution may be increased to 50 mL. VENT most of the
air bubbles, and SEAL with a clamp (A.4.14) at the 20 cm mark as shown in
Figure A.1 b) to seal the liquid.
A.6.2.3 PLACE the gloves on an oscillator (A.4.15) and OSCILLATE at (25 ±
5) °C for (120 ± 5) min.
A.6.2.4 REMOVE the clamp and carefully SEPARATE the gloves. Be careful
not to contaminate the leachate with the staining solution. If the leachate is blue,
it shall be discarded and re-leach with new gloves.
A.6.2.5 TRANSFER the leachate to the centrifuge tube (A.4.3),
CENTRIFUGATE for 15 min at 2000 g, or FILTER with disposable filter
membrane (A.4.4), or use both methods, to make the leachate clear. The
prepared clear liquid may be refrigerated at 2 °C ~ 8 °C and determined within
48 h, and may also be frozen below -18 °C before analysis, for not more than
two months.
A.6.2.6 CUT the wrist of the outer glove at 20 cm above the immersed outer
glove, WIPE the surface liquid with absorbent paper, DRY at room temperature,
WEIGH (m2), to the nearest 0.1 g. CALCULATE the mass of the leaching part
of the glove.
A.6.3 Protein standard solution
A.6.3.1 Protein stock solution
DISSOLVE 25 mg of ovalbumin in 25 mL of leaching buffer solution (A.3.2.2) to
prepare the ovalbumin solution with a nominal concentration of 1 mg/mL.
FILTER with 0.22 μm filter membrane (A.4.4), USE a UV spectrophotometer to
measure the absorbance with a quartz cell (A.4.7) at 280 nm, CALCULATE the
actual ovalbumin concentration. Absorbance divided by 0.7153) is the actual
concentration (mg/mL). The solution may be kept stable for 2 d under
refrigeration conditions, and may be kept stable for two months at below -18 °C.
To thaw, it needs to be heated at 45 °C for 15 min.
A.6.3.2 Protein standard solution
USE leaching buffer solution (A.3.2.2) to dilute the stock solution to prepare
series standard solutions (A.6.3.1). MAKE the concentration of solutions are
approximately 100 μg/mL, 50 μg/mL, 20 μg/mL, 10 μg/mL, 5 μg/mL and 2
μg/mL. USE leaching buffer solution as blank. These solutions may be kept
stable for 2 d under refrigeration conditions, and may be kept stable for two
months at below -18 °C. To thaw, it needs to be heated at 45 °C for 15 min.
A.6.4 Precipitation and concentration of proteins
A.6.4.1 CARRY OUT a parallel test at (25 ± 5) °C.
A.6.4.2 Accurately pipette 1 mL of blank solution, protein standard solution
(A.6.3.2) and four glove leachates (A.6.2.5) to 6 microtubes (A.4.6), respectively.
(To each tube) ADD 0.1 mL of DOC (A.3.5), VORTEX and LET STAND for 10
min; (to each tube) ADD 0.1 mL of TCA (A.3.6) and 0.1 mL PTA (A.3.7),
VORTEX and LET STAND 30 min.
A.6.4.3 CENTRIFUGE at 6000 g for 15 min. POUR OUT the supernatant,
PLACE each centrifuge tube inversely on absorbent paper for 5 min.
A.6.4.4 ADD 0.2 mL of 0.1 mol/L sodium hydroxide solution (A.3.4) to each test
tube including the blank (respectively). MIX on the vortex mixer to re-dissolve
the precipitated protein. Make sure the protein is completely dissolved into clear
solution. Some gloves need to be refrigerated at (5 ± 3) °C overnight. If there
are still precipitates, gradually add calibrated sodium hydroxide solution, add
0.20 mL each time, up to a total of 1 mL. USE an integral multiple of 0.2 mL in
all subsequent steps. Diluting this sample leachate before precipitation may be
effective.
NOTE. The purpose of re-dissolving the protein is to purify the protein and eliminate
the interference. It is inevitable that there will be a certain amount of protein loss during
this process. This test assumes that the percentage loss of the protein standard
solution is the same as the percentage loss of the sample leachate, however, the loss
should be minimized because the excess loss is not reproducible.
A.6.5 Color development
3) Assuming that the molecular weight is 43000 D, 280 nm and 30745 molar extinction, and in a 1 cm
colorimetric cuvette at pH 7.4, the extinction of 1 mg/mL ovalbumin in the 0.1 mol/L TES buffer solution
at pH 7.4 is 0.715.
A.6.5.1 The method described in this Part uses commercially available kits for
validation. Other kits or self-prepared reagents may require different volumes
and incubation times.
A.6.5.2 ADD 0.125 mL of reagent A (A.3.3.1) to the micro test tube containing
the re-dissolved protein solution and the blank micro test tube. MIX well. ADD
1 mL of reagent B (A.3.3.2), COVER the lid. VORTEX MIX for 30 min to make
color developed completely. At this stage, it may produce precipitates, which
shall be centrifuged or filtered before measuring the absorbance.
A.6.6 Measurement
A.6.6.1 Microplate reader
PIPETTE a certain amount of solution (A.6.5.2) into the hole of the ELISA plate
(A.4.8), FILL the hole, for example, fill 490 μL in a 500 μL ...
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(Above excerpt was released on 2018-05-05, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/YYT0616.1-2016