This report describes the automation of colorimetric and fluorometric methods for the determination of low levels of formaldehyde and related compounds in drinking water, natural water and industrial effluents.the fluorometric method is based on the reaction of formaldehyde with 2, 4 -pentanedione and ammonia to form a fluorescent product. The colorimetric method utilizes chromotropic acid andThe fluorometric method was found to be much more specific than the colorimetric procedure and both methods are capable of determining formaldehyde down to 10 ugllitre at a rate of 10 -20 samples per hour.The results of a preliminary survey,concerning the occurrance of formaldehyde and related compounds in a wide variety of samples, ranging from drinking waters to industrial effluents, are also reported.The results indicate that considerable quantities of these conpounds are present in some waters receiving industrial wastes and these results 53Copyright01974 by Marcel Dekker, fnc. All Rights Reserved. Neither this work nor any part may b e reproddced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing from the publisher. Downloaded by [University of Florida] at 17:03 10 June 2016 AFGHAN ET AL. also show that those samples which contain formaldehyde also indicate the presence of other carbonyl compounds.

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Silicone oils were microencapsulated within polyamide (nylon) membranes cross‐linked with polyethylenimine for use as an oxygen carrier in aerobic fermentation. The use of 20% microcapsule dispersions enabled a four‐ to five‐fold increase in volumetric oxygen transfer coefficient (kLa), with or without the presence of cells. The improvement in oxygen transfer rates was due to the greatly increased specific surface area of the carrier in comparison to conventional bubble aeration. The production rate of dihydroxyacetone (DHA) from glycerol with Gluconobacter oxydans was increased from 1·5 to 9 mmol dm−3 DHA h−1 with the introduction of 20% of microcapsules in a batch fermentation and from 6 to 8 mmol dm−3 DHA h−1 in a fluidized bed fermentation. It is expected that the oxygen‐permeable polymeric membrane coating the silicone oils should reduce the toxic or inhibitory effects previously observed with other oil‐based oxygen carriers, and will eliminate the need for toxic chemical dispersants in the medium. Also, microencapsulated oxygen carriers avoid the need for vigorous agitation to maintain a dispersion of the oxygen carrier. © 1997 SCI.

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Silicone oils were microencapsulated within polyamide (nylon) membranes cross‐linked with polyethylenimine. Solubility of oxygen within the silicones, whether encapsulated or not, was approximately 6 mmol dm−3, representing solubilities approximately 20‐fold higher than that of oxygen in water. The response time of oxygen transfer from the microencapsulated oxygen carrier was less than 2.5 s; a more precise measurement was limited by the response time characteristics of the oxygen probe. Assuming that the bioreactor volume consists of 10–20% (v/v) microencapsulated silicone oil, this represents an enhancement of the oxygen reservoir by a factor ranging from 4 to 7 and improvement in oxygen transfer rates greater than 15‐fold due to the greatly increased specific surface area in comparison to conventional bubble aeration. Circulation of oxygenated silicone oils encapsulated within inert polymeric membranes may provide an efficient alternative to bioreactor oxygenation with shear sensitive cell systems, or in fermentations with high oxygen requirements.