Processing kodak motion picture films, module 3 analytical procedures
Share Embed Flag
Download ePaper

Processing kodak motion picture films, module 3 analytical procedures

Processing kodak motion picture films, module 3 analytical procedures Processing kodak motion picture films, module 3 analytical procedures

motion.kodak.com
from motion.kodak.com More from this publisher
22.07.2013 Views

2 Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03

Iodometric Determination of Total Sulfite in Reversal Color Developers Containing KODAK Reversal Agent, RA-1 ECR-1303 Process ECN-2 ECP-2D VNF-1/LC RVNP Formulas — — DR-150/151 DR-150 INTRODUCTION KODAK Reversal Agent, RA-1 contributes a positive interference to the iodometric determination of the total sulfite in a color developer. The effect of this interference can be corrected if the concentration of RA-1 is known. The iodometric titration and known reversal agent concentration can then be used to calculate the real concentration of sodium sulfite in the sample. PRINCIPLE For the iodometric titration, the developer sample is added to an excess of iodine, formed by acidifying standard potassium iodate solution and adding potassium iodide. Part of the iodine is reduced to iodide by the sulfite in the sample; the remaining iodine is measured by titrating it with standard sodium thiosulfate using starch indicator. Since the quantity of sulfite is equivalent to the quantity of reduced iodine and since the quantity of sodium thiosulfate used in the titration is equivalent to the quantity of remaining iodine, the difference between the total iodine and the volume of sodium thiosulfate is a measure of the sodium sulfite concentration. In developers containing RA-1, some iodine is also reduced by the reversal agent and this will erroneously be calculated as sulfite unless a correction is made. The RA-1 is analyzed using Method ECR-0001-1 (or subsequent revision). This method requires handling potentially hazardous chemicals. Consult the Material Safety Data Sheet for each chemical before use. MSDS's are available from your chemical supplier. Note: Use pipets and volumetric glassware meeting the “Class A” definition by the National Institute of Standards and Technology (NIST). RELIABILITY Photographic-grade sodium sulfite (Na 2 SO 3 ) is usually less than 100 percent pure (minimum assay is 98.5 percent). Photographic-grade sodium bisulfite (NaHSO 3 ) is a mixture of sodium bisulfite, sodium metabisulfite (Na 2 S 2 O 5 ), and water. Its purity, as determined by an iodine titration and expressed as sodium bisulfite, is approximately 107.5 percent. If it were pure sodium metabisulfite it would assay 110 percent as sodium bisulfite. One gram of photographic-grade sodium bisulfite is equivalent to 1.30 grams of sodium sulfite (100 percent). Correction equations were calculated from ten analyses of sodium sulfite in color developer with RA-1 concentrations ranging from 0 to 125 mg/L. The 95 percent confidence limits are essentially the same for developers with or without RA-1. The 95 percent confidence limits for an individual determination are ± 0.05 g/L sodium sulfite. Reagents Use ACS Reagent Grade reagents unless otherwise specified. 0.1 N Potassium Iodate, KIO 3 (standardized to 4 decimal places) 7.0 N Sulfuric Acid, H 2 SO 4 0.60 M Potassium Iodide, KI 0.1 N Sodium Thiosulfate, Na 2 S 2 0 3 (standardized to 4 decimal places) Starch Indicator Processing KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03 1

2 <strong>Processing</strong> KODAK Motion Picture Films, Module 3, Analytical Procedures H24.03

logo

products

Resources

Company

Terms of service
Privacy policy
Cookie policy
Cookie settings
Imprint
Change language
Made with love in Switzerland
© 2024 Yumpu.com all rights reserved

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!