Formaldehyde elution

Interpretation for Comminuted Systems. The similarities and differences noted for the kinetics of formaldehyde removal from UF and PF particleboards and from formaldehyde-sorbed wood are brought out more clearly by plotting relative formaldehyde losses versus time. Loss ratios, i.e., formaldehyde loss by any material divided by the UF board loss at the same time, are shown in Figures 10 and 11 included in Figure 10 are analogous ratios for resin data from formaldehyde liberation (weighing bottle test) and formaldehyde elution by toluene experiments (10). Examination of the data leads to the following additional comments ... 

Lord and Pawliszyn" developed a related technique called in-tube SPME in which analytes partition into a polymer coated on the inside of a fused-silica capillary. In automated SPME/HPLC the sample is injected directly into the SPME tube and the analyte is selectively eluted with either the mobile phase or a desorption solution of choice. A mixture of six phenylurea pesticides and eight carbamate pesticides was analyzed using this technique. Lee etal. utilized a novel technique of diazomethane gas-phase methylation post-SPE for the determination of acidic herbicides in water, and Nilsson et al. used SPME post-derivatization to extract benzyl ester herbicides. The successful analysis of volatile analytes indicates a potential for the analysis of fumigant pesticides such as formaldehyde, methyl bromide and phosphine. 

Diglycidyl ether of bisphenol A (DGEBA, MW 340 Da) and 4,4 -dihydroxy-diphenylmethane (DHDPM, MW 200 Da) were analysed by SEC-MALS [784]. DGEBA and DHDPM are the basic oligomers of epoxy resins and phenol-formaldehyde condensates, respectively, which are widely used in the electronic and automotive industries. Excellent reproducibility ( 1 %) and good accuracy (better than 10%) were observed. SEC has also been used for the determination of mineral oil in extended elastomers [785] and in PS [178]. With heptane containing 0.05% isopropanol as the mobile phase, mineral oil is completely unretained and elutes before the solvent via SEC all other components in a PS extract are retained on silica and elute after the solvent peak. 

This method, although described for indoles, probably also worlds with 5-OH-tryptamine (serotonin), and 5-OH-DMT (bufotenin) with compounds of the latter type, orally active psilocybin analogs will be obtained in one step. Dissolve 5 g 5-OH-indole (or analog) in 25 ml ethanol. Add 5.5 g 33% aqueous dimethylamine (or other amine, e.g., piperidine) and add slowly dropwise with stirring 3.5 g 38% aqueous formaldehyde. Two minutes after the end of the addition shake with water and CHCI3 dry and evaporate in vacuum the CHClj phase to get 5 g oily 4-dimethyl-aminomethyl-5-OH-indole (1) (can chromatograph on 100 g alumina and elute with ethyl acetate). It has been claimed that this method does not work. 

System (3) described the use of stable-isotope-dilution mass spectrometry for the simultaneous determination of cortisol, cortisone, prednisolone, and prednisone in plasma [177]. Cortisol, cortisone, prednisolone, and prednisone were simultaneously extracted from acidified plasma on a Sep-Pak Ci8 cartridge. The column was eluted with methanol, the eluent evaporated, and the residue compounds reacted to their bismethylenedioxy-3-heptafluoro-n-butyryl derivatives by treatment with formaldehyde and heptafluoro-n-butyric anhydride. The derivatives were... 

The use of the anion-exchange resin Duolite A-7 for concentrating organic acids was reported as early as 1965 by Abrams and Breslin (7) and more recently by Leenheer (8). A-7 is a high-surface-area, macro-porous, phenol-formaldehyde, weak-base resin. This resin combines weak-base, secondary-amine functional groups with the relatively hydrophilic phenol-formaldehyde matrix to effectively sorb and elute organic acids. 

Derivatization is a procedure in which analyte is chemically modified to make it easier to detect or separate. For example, formaldehyde and other aldehydes and ketones in air, breath, or cigarette smoke25 can be trapped and derivatized by passing air through a tiny cartridge containing 0.35 g of silica coated with 0.3 wt% 2,4-dinitrophenylhydrazine. Carbonyls are converted into the 2,4-dinitrophenylhydrazone derivative, which is eluted with 5 mL of acetonitrile and analyzed by HPLC. The products are readily detected by their strong ultraviolet absorbance near 360 nm. 

TO-11 DNPH-coated adsorbent cartridge elution with acetonitrile HPLC analysis Formaldehyde... 

These treatments convert to ionic substances, and remove, nearly all constituents of natural materials the acid treatments release any inositol present as phosphate, or combined in phospholipids, glycosides, etc. Glycerol remains in the deionized sample, but it can be oxidized separately, or be removed by heat decomposition or by repeatedly evaporating the solution to dryness. Such polyhydric alcohols of greater chain length as erythritol and mannitol, when present, would still interfere. However, corrections can be made for these compounds by determining the formaldehyde which they form on periodate oxidation, or they may be removed by chromatography on filter paper. The micro-periodate method is well suited to the analysis of samples eluted from filter paper, provided that care is exercised to remove the tiny particles of cellulose which are usually found in such eluates. 

To a solution of the S-(+)-4-acethoxy-9-[2-(5-ethyl-l,2,3,6-tetrahydro-pyridin-3yl)-l-(lH-indol-2-yl)-l-methoxycarbonyl-ethyl]-3a-ethyl-5-hydroxy-8-methoxy-6-methyl-3a,4,5,5a,6,ll,12,12b-octahydro-lH-6,12a-diaza-indeno[7,l-ca]fluorene-5-carboxylic acid methyl ester in dioxane and glacial acetic acid was added 37% aqueous formaldehyde and the mixture stirred at 35°C for 24 h. The solution was evaporated in vacuo and the residue suspended in chloroform and washed with cold aqueous 5% K2C03 solution. The chloroform layer was dried (MgS04), filtered, and evaporated. The residue was chromatographed eluting with EtOAc/MeOH, 10% NH4OH to give the product navelbine. 

Separation of aldehyde dinitrophenylhydrazines by TLC and column chromatography Excess dinitrophenylhydrazine reagent and the hydrazones of acetone, formaldehyde and acetaldehyde, which occur as contaminants, can be removed prior to preparative TLC by column chromatography. Silicic acid (Merck) columns (3x2.1 cm) may be used with chloroform to elute the aldehyde dinitrophenyl-hydrazones. 

The top of the moving band in the column was the 2,4-dinitrophenylhydrazone of formaldehyde. This was cut from the column and eluted with ether yield, 34% melting point, 164-5° C. Literature value, 166° C. 

Cell cultures provide infected fluids that contain little debris and can generally be satisfactorily clarified by filtration. Because most viral vaccines made from cell cultures consist of live attenuated virus, there is no inactivation stage in their manufacture. There are, however, two important exceptions inactivated poliomyelitis virus vaccine is inactivated with dilute formaldehyde or (3-propiolactone and rabies vaccine is inactivated with (3-propiolactone. The preparation of these inactivated vaccines also involves a concentration stage — by adsorption and elution of the virus in the case of poliomyelitis vaccine and by ultrafiltration in the case of rabies vaccine. When processing is complete the bulk materials may be stored until needed for blending into final vaccine. Because of the lability of many viruses, however, it is necessary to store most purified materials at temperatures of —70°C. 

In accordance with a description by Blasius and coworkers a condensation resin was synthesized from phenol and formaldehyde which contains dibenzo[18]crown-6 anchor groups . The structure of this resin can be seen in Fig. 6 in connexion with Fig. 11. The capacity of this resin was determined to be 0.85 mmol/g for the uptake of calcium ions from a methanolic solution of CaClj. 0.052 mmol Cal2 were eluted from a column with a mixture of 30% methanol/70% tetrahydrofuran (v/v) (2.4 g resin, particle size = 45-90 pm). The elution curve is given in Fig. 15 . 

Tsuchiya K, Hayashi Y, Onodera M, et al. 1975. Toxicity of formaldehyde in experimental animals -concentrations of the chemical in the elution from dishes of formaldehyde resin in some vegetables. 

Formaldehyde Removal By Gas Elution. These experiments involve the continuous collection of formaldehyde removed by a controlled flow of gas over the wood samples. Variables studied include time, gas flow rate, sample comminution, gas type, humidity, and adhesive type. 

Eluant Gas Effects on Gas Elution. Very brief tests were made to compare the effectiveness of dry N2, CO and CO2 as eluants (Figure 2). The three gases provided no differentiation between formaldehyde states in UF board. 

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