This standard applies to the determination of thiosulfate residues in color and black-and-white films within two weeks after development. The range of the thioate content in the microfilm is 0.1~45ug/cm^2. The residual sulfate content of microfilm for long-term and permanent preservation shall not exceed 0.7~45ug/cm^2. GB/T 7519-1987 Determination of thiosulfate residues in microfilm after development by microphotography technology Methylene blue photometric method GB/T7519-1987 Standard download decompression password: www.bzxz.net
This standard applies to the determination of thiosulfate residues in color and black-and-white films within two weeks after development. The range of the thioate content in the microfilm is 0.1~45ug/cm^2. The residual sulfate content of microfilm for long-term and permanent preservation shall not exceed 0.7~45ug/cm^2.

National Standard of the People's Republic of China
Micrographic Technology
Determination of residual thiosulphate in processed microfilm
Methylene blue photometric method
Micrographies
Determination of residual thiosulphatein processed microfilm-Methylene blue metbpd1 Applicable scope
UDC778.14
GB 7519-87
This standard applies to the determination of residual thiosulphate in colour and black-and-white films within two days after processing. The range of the thiosulphate content of the microfilm to be determined is 0.1 ~ 45g/cm2. The residual thiosulphate in microfilms stored for a long time and for a long time shall not exceed 0.7/cm2.
2 Asthenocyanine blue method
2.1 Overview of measurement
Thiosulfate is extracted from the sample, reduced to sulfide by potassium borate, and then reacted with N,-dimethylaminodiamine to form asthenocyanine blue. Methylene blue has a peak absorption at 65 nm. The absorbance can be measured by a spectrophotometer, and the content of thiosulfate ions can be found from the standard curve. For this determination, a standard curve should be made first. This standard curve should be similar to Figure 1. 2.2 Film with gelatin coating on both sides of the base
The content of thiosulfate in microfilm with gelatin coating on both sides is about one-fold that of the coating on one side. The calculation method for the measured value of this type of material is shown in Example 4.
2.3 Determination range of content
The content range determined by this method is very wide. The corresponding measurement range can be obtained by selecting three different test procedures. Procedure I: The content of the determination is 0.10.9ug/cm2 Procedure II: The content of the determination is 0.9 ~ 4.5g / cm2 Procedure III: The content of the determination is 4.5 ~ 45μg / cm2 2.4 Reagents
Only double distilled water or deionized water can be used during the analysis. Note that water that has flowed through a copper channel cannot be used. Potassium iodide (GB1272-77): analytically pure: b.
Potassium bromide (GB649-77): analytically pure: Potassium dihydrogen phosphate (GB1274-77): analytically pure Potassium borohydride: chemically pure
N-butyl ketone (GB 686-78), analytically pure,
Ferric sulfate: analytically pure:
Sulfuric acid (GB625-77): analytically pure
"Methyl-p-phenylenediamine sulfate: chemically pure: h.
Approved by the National Bureau of Standards on March 26, 1987
Implementation on December 1, 1987
, Silica, chemically pure,
GB 7619-87
J. Sodium hydroxide (GB62991) analytical grade
k, sodium thiophosphate (GB637-77) analytical grade. 2.5 Test solution preparation
2.6.1 Extraction solution
1.0g potassium iodide, 20.0g potassium iodide and 1.0g potassium monohydrogen phosphate are dissolved in 1000ml water. The validity period of this test solution is 8 months.
2.5.2 Potassium borohydride test solution Note
Dissolve 3.0g potassium borohydride (KBH) in 100ml of 0.2mol Sodium hydroxide solution. The test solution should be placed in a cool place and is valid for one week. Potassium borohydride is flammable. When it comes into contact with water or dilute acid, it releases hydrogen. It reacts with acid to release gases that are harmful to the human body. At high concentrations, it can cause severe skin burns. Be especially careful when using it. Potassium borohydride is a strong ash agent. Avoid contamination of unexposed film or developer: Wash hands and equipment thoroughly after using potassium borohydride.
2.5.8 Ferrous sulfate test solution
Slowly add 15ml of concentrated sulfuric acid into a beaker containing 89ml of water and stir until smooth. Dissolve 3.0g of ferric iodide. The validity period of this test solution is 2 months.
Note: Avoid contact with skin and eyes. If contact occurs, rinse with water. 2.5.4N, N-dimethyl-p-phenylenediamine sulfate test solution (NND test solution) Slowly add 15ml of concentrated sulfuric acid into a beaker containing 89ml of water, stir well, dissolve 1.0g of N, N-dimethyl-p-phenylenediamine sulfate, and then add 5g of powdered silica gel and stir until all the colored substances are adsorbed. After the adsorbate is precipitated, pour out the upper clear liquid for use. The validity period of this test solution is 8 months. ||t t||2.5.5 Sodium thiosulfate (concentration 0.1 mol/L) standard solution Dissolve 24.8 g sodium thiosulfate (containing 5 crystal waters) in 500 ml water and dilute to 1000 ml for later use. 2.6 Apparatus
2.8.1 A 10-cm2 colorimetric arm with a polyethylene stopper or glass case is used to hold the film sample. 2.6.2 Spectrophotometer.
2.7 Procedure I
This procedure is suitable for the determination of stable black-and-white microfilm after washing and selection, and its thiosulfate content is within the range of 0.1 to 0.9 g/cm2.
2.7.1 Film Sample
Select a 10 cm2 sample from the minimum density area. Fold it into a W shape, place it in a 10-meter colorimetric tube (2.6.1), add 5.0 ml of the extract (2.5.1), and place it at room temperature for 20 minutes, shaking it from time to time. When taking out the film sample with tweezers, the loss of the liquid should be minimized.
2.7.2 Take 4 dropper bottles, fill them with C and various test samples prepared previously (2,5.2~2.5.4). 2.7.8 First, drop 5 drops of potassium hydride test solution (2.5,2) into the colorimetric tube in 2.7.1, stir to mix, and immediately move to the next step after 5 seconds.
2.7.4 Then drop 10 drops of C, shake to mix, and immediately move to the next step after 5 seconds. 2.7.5 After adding 5 drops of ferric sulfate test solution (2.5.3) and 5 drops of NND test solution (2.5.4), immediately plug the tube. 2.7.6 Plug the tube tightly, shake the colorimetric tube vigorously for 1 minute, and open the plug from time to time to release air. Let it stand for 3 to 5 minutes until the red color in the solution disappears. If the solution never turns red, it indicates that the content of thiosulfate is too high. Use procedures II and A to retest. 2.7.7 At a wavelength of 665nm, use air as a blank and use a spectrophotometer to measure the absorbance of the solution. If the data is less than 0.001, the content of thiosulfate can be found from the standard curve. 2.1.8 According to the absorbance of the solution, find the content of thiosulfate in every 5 ml from the standard curve. Divide it by 10 for single-sided coated film (see Example 1) and divide it by 20 for double-sided coated film (see Example 4) to get the content of thiosulfate per square centimeter. Multiply the thiosulfate content by 1.4 to get the content of anhydrous sodium thiosulfate. 2. Daily procedure The procedure is suitable for thiosulfate content of 0.9~～4.5μg/ 2.8.1 Take a film with an area of ​​10 cm2 and place it in the 25 ml extraction solution (2.5.1) at room temperature F for 20 minutes, shaking occasionally. 2.8.2 Use a pipette to take 5 ml from the 25 ml extraction solution and place it in a 10 ml colorimetric tube (2.6.1), then follow steps 2.7.2 to 2.7.6:
2.B.3 Use a spectrophotometer (2.6.2) to measure the absorbance of the solution at a wavelength of 665 nm. If the absorbance is lower than 0.80, the thiosulfate content (X) can be determined from the standard curve. 2.8.4 Multiply X by 0.5 to obtain the thiosulfate content per square centimeter of film (see Example 2). 2.8.5 If the absorbance is greater than 0.80, it indicates that the thiosulfate content exceeds 4.5 g/cm2. In this case, Procedure III should be used. 2.9 Procedure III
This procedure is suitable for determining the thiosulfate content of microfilm with a thiosulfate content of 4.5 to 45 g/cm2. 2.9.1 Use a pipette to transfer 10 112.8.1 Place the prepared solution in a 100 l volumetric flask and dilute it to 100 ml with fresh extract solution. 2.9.2 Use a pipette to transfer 5 ml of the diluted solution to a 100 l colorimetric tube and then follow the steps of 2.7.2 to 2.7.6. 2.9.3 Follow 2.8.3.
2.9.4 Multiply X by 5 to obtain the content of thiosulfate per square centimeter (see Example 3). 2.9.5 If the absorbance is greater than 1.80, it indicates that the thiosulfate content exceeds 45 μg/cm2. 2.9.6 If the double-sided coating is thin, calculate according to Example 4. 2.10 Industry Standard Curve
2.10.1 Preparation of Sodium Thiosulfate Standard Solution The test solution must be prepared in the same volume. Use a pipette to take 25.0 ml of the sodium thiosulfate standard solution (2.5.5) Pour into a 500ml volumetric flask, dilute with water to 5ulml, and cut evenly. Take out 5ml of the solution with a pipette bench, inject it into a 250ml volumetric flask, dilute with water to 250ml, and mix to calculate the solution containing 11.2g of thiosulfate (S.0-) per ml. 2.10.2 Use 1.0ml and 5.Uml pipettes to draw standard sodium thiosulfate solution and extract solution respectively according to the table below, and put them into four colorimetric tubes in turn.
2.10.3 Operate various test solutions according to steps 2.7.2 to 2.7.7. 2.10. Use the absorbance of the test solution and the corresponding thiosulfate content as the vertical and horizontal coordinates to draw a standard curve. This curve should be similar to the curve in the figure.
Standard solution for preparing standard curve
Reagent plate, ml
Colorimetric tube number
Sodium thiosulfate standard solution 11.2μg/ml
Extract solution
Thiosulfate content of standard solution (S09-) #g/5ml
GB T61-$T
Thiosulfate content of standard solution (S09-) #g/5mlMethylene blue standard curve
Example 1: Using procedure I, assuming that the absorbance of the 10cm film test is 0.632, the thiosulfate content is found to be 7.2μg/5ml from the standard curve.
Calculation: bzxz.net
=0.7%/cm3 is the thiosulfate content per square centimeter of the film. Example 2: Using procedure II, assuming that the absorbance of the 10c film test solution is 0.400, the thiosulfate content is 4.1 μg/5 ml from the standard curve.
Calculation:
5 ×10
= 2.0 / cm, which is the thiosulfate content per square meter. Example 3: Using procedure III, assuming that the absorbance of the 10cm film test solution is 0.400, the thiosulfate content is 4.1g/5ml from the standard curve.
Calculation:
4.1×25 × 100
10× 5 ×10
=20.5μg/cm, which is the thiosulfate content per square centimeter. Example 4: Use procedures I, II, and III to test the film with coatings on both sides, and multiply the test results by 1
to get the content of thiosulfate on each side. Additional notes:
GB7619-8T
This standard was proposed by the Information Classification and Coding Research Institute of the National Bureau of Standards. This standard was drafted by the Archives Department of Renmin University of China. The main drafters of this standard are Liu Fengzhi, Yu Lianxiang, Chen Leixu, and Fan Yaozhuang
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