Hydroxylamine Method

The pH of the mixture was adjusted to 7.5 by adding a saturated sodium bicarbonate solution. After being washed twice with diethyl ether, the reaction solution was acidified to pH 2 with dilute hydrochloric acid and extracted with ether. The ether solution containing the free penicillin was washed twice with water and then extracted with 50 ml of N potassium bicarbonate solution. After freeze drying of the obtained neutral solution, the potassium salt of o-azidobenzylpenicillin was obtained as a slightly colored powder (11.2 grams, 54% yield) with a purity of 55% as determined by the hydroxylamine method (the potassium salt of penicillin G being used as a standard). 

Vollmer et al. [4] compared the Hg(II) acetate method described in the Code of Federal Regulations for the determination of penicillamine in bulk drug and formulations with (i) a nonaqueous lithium methoxide titration, (ii) a nonaqueous HCLO4 titration, and (iii) a colorimetric method with hydroxylamine. Method (ii) was unsatisfactory for bulk determinations. Method (i) was less precise than the Hg(II) acetate method, but gave satisfactory results for bulk drug and capsule samples. Method (iii) was the only method that gave satisfactory results in the presence of EDTA. 

These values of carbonyl oxygen are not determined by the present authors but are taken rank-wise from Blom s determination by hydroxylamine method (4). These values are considered to be the maximum estimate for carbonyl oxygen and are about double the estimate obtainable by phenylhydrazine method (Table II). The latter method is suspect... 

This procedure measures citral content in lemon oil using acid/base titration. It has been modified from the hydroxylamine method, and is from AOAC Method 955.38 (AOAC, 1990d). 

Other methods of determining citral (aldehydes) are that of Soldaim and Bertd and that of Romeo (Ann Lab Camera dt Commercio di Messina, 1908) Results obtained by Kleber s phenylhydrazine method or Walther and Bennet s hydroxylamine method are sometimes required m the trade, the latter gives lower results than other methods... 

The resulting solution was treated as described in Example 1 to give the potassium salt of a-azidobenzylpenicillin as a white powder (29.4 grams, 84% yield) with a purity of 83% as determined by the hydroxylamine method (the potassium salt of penicillin G being used as a standard). 

Assay Accurately weigh about 1 g of sample, and determine as directed in the Hydroxylamine Method under Aldehydes and Ketones, Appendix VI, using 76.10 as the equivalence factor (e) in the calculation. 

Alcoholic Sulfuric Acid, 0.5 N, 859 Alcoholic Sulfuric Acid, 5 N, 859 Alcohols, Total, 815 ALDC Activity, (S3)110 Aldehyde C-6, 504 Aldehyde C-7, 502, (S3)76 Aldehyde C-8, 540 Aldehyde C-9, 538 Aldehyde C-10, 476 Aldehyde C-ll Undecyclic, 560 Aldehyde C-ll Undecylenic, 560 Aldehyde C-12,518 Aldehyde C-12 MNA, 534 Aldehyde C-14 Pure, So-Called, 560 Aldehyde C-16, 492 Aldehyde C-18, So-Called, 538 Aldehyde-Free Alcohol, 849 Aldehydes and Ketones, 816 Hydroxylamine Method, 816 Hydroxylamine/Tert-Butyl Alcohol Method, 816... 

Assays for Certain Aldehydes and Ketones (Flavor Chemicals), 564 Aldehydes—Hydroxylamine Method, 564... 

Aldehydes—Hydroxylamine/Tert-Butyl Alcohol Method, 564 Ketones—Hydroxylamine Method, 565 Procedure Requiring the Use of Sealed Glass Vials or Ampules, 564... 

The structure of /8-diketones of the selenophene series was found by physical129 (UV, IR, and NMR spectra) and chemical75,98 99 (reaction with hydroxylamine) methods. 

Essential oils - Determination of carbonyl value - Free hydroxylamine method... 

A mixture of 150 g (0.89 mol) of ( —)-e (fo,e.vo-2-hydroxy-2,6,6-trimethylbicyclo[3.1.1]hcptan-3-one [( — )-l-hy-droxypinocamphone], freshly distilled 150 g (0.73 mol) of AI(0-i -Pr)3 and 150 g (2.5 mol) of /-PrOH is heated in a 2 L flask with distillation column. A gentle reflux is maintained so that 30 g of the acetone/ -PrOH mixture distills per hour, which is replaced by the same volume of fresh i-prOH. When the formation of acetone ceases (ca. 3-4 h), the excess /-PrOH is distilled off and the residue is stirred for 1 h with weakly alkaline water. The mixture is filtered and the residue extracted with Ft.O. The extract contains ca. 15% of starting material which is removed by fractional crystallization (hydroxylamine method) to afford the crude diol yield 75 g (49%) mp 35 40 JC. Purification via the phenylurethane gives mp 55.5-56X [a]f,° -J-3.3 (EtOH). 

A comparison of procedures for the determination of acetaldehyde was made by Iribarne, (1941). The colorimetric Schiff, the bisulfite procedure, and the hydroxylamine method were compared. In general, the bisulfite procedure gave a better and more regular recovery, but on 49 wines it showed only 101 mg. per liter of aldehyde, and the hydroxylamine, 104. 

Stillman, R.C. and R.M. Reed, 1932. Hydroxylamine method for the determination of aldehydes and ketones in essential oils. Perfumery Essential Oil Record, 23 278. 

Determination of the carbonyl value—free hydroxylamine method ISO 1271) The determination is done by converting the carbonyl compounds to oximes by reaction with free hydroxylamine liberated in a mixture of hydroj lammonium chloride and potassium hydroxide. 

Stadman, E.R. (1957) Preparation an Assay of acyl Coenzyme A and other Thiol Esters Use of hydroxylamine. Methods EnzymoL, 3, 931-941. 

Aldehydes and ketones. Bisulfite method, neutral sulfite method, phenylhy-drazine method, hydroxylamine method. 

As oils are still commonly sold in the trade on the figure obtained by neutral sulphite or bisulphite absorption, these methods are briefly described below. They act as a useful check on the hydroxylamine method and the neutral sulphite method is especially suitable for caraway and dill oils, separation being particularly clean and the results less likely to be complicated by adulterants than in the case of other oils. 

The hydroxylamine method in which the mineral acid, liberated from hydroxylamine salts by oxime formation with the aldehyde, is titrated direct, requires to be modified according to the particular aldehyde or ketone being determined (Bennett and Cocking" ). The advantages of the hydroxylamine process over the absorption methods given above are recognised as (a) the hydroxylamine method is a definite determination of aldehydic or ketonic substances, whereas the absorption methods include impurities such as water-soluble organic acids and adulterants such as alcohol (d) a small quantity only of the oil is required and the determination can be completed in a much shorter time. Yet it must be pointed out... 

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