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Sample analytical

It is important to realise that all compounds formed biochemically can be broken down biochemically, and that micro-organisms are also capable of degrading xenobiotics (unnatural synthetic compounds). It should also be realised that many microbial communities are much more effective at degrading chemicals than the sum activities of their component species. [Pg.16]

The rate of deterioration of any product depends on a number of factors, the important ones being the chemical structure, physical characteristics, the type of micro-organisms present, the number of micro-organisms present, temperature, pH, and the water content (.4 ). [Pg.16]


Analyte Sample Volume Sample (liL) Concentration Range Sampling Frequency (h-1)... [Pg.656]

Nutritional Labeling Descriptors. In order to avoid confusion, descriptive terms must be accompanied by definitions which adequately explain the terms. In the case of nutrition-related claims, analytical sampling offers a means of assuring the accuracy of the stated claims. The USDA s FSIS has proposed a Hst of descriptors relevant for meat and poultry products (Table 3). [Pg.35]

Determination of accuracy and precision should be made by analysis of repHcate sets of analyte samples of known concentration from equivalent matrix. At least three concentrations representing the entire range of the caUbration should be studied one near the minimum (MAQ), one near the middle, and one near the upper limit of the standard curve. [Pg.243]

A solution of 2 g of sodium borohydride in 5 ml of water is added at room temperature to a solution of 1 g of 3a-hydroxy-5jS-pregnane-l 1,20-dione in 15 ml of methanol. Almost immediately, crystals begin to form. After the mixture has been kept overnight, the precipitate is collected with suction to yield 0.8 g of the diol, mp 230-232°. The analytical sample, crystallized once more from aqueous methanol, melts at 231.4-232.6° [a]p 31.2° (acetone). Reported mp 236-238°. [Pg.93]

When 3a,17a-dihydroxy-5jS-pregnane-ll,20-dione is allowed to react at room temperature overnight with sodium borohydride in aqueous methanol, no crystals form and only 5j5-pregnane-3a,l ljS,17a,20j5-tetrol is isolated in good yield. If the reaction is halted at the end of 3 h y the addition of water and extraction with chloroform, it is possible xo obtain a 55% yield of 3a,17a,20jS-trihydroxy-5j5-pregnan-ll-one, mp 218-220°,after recrystallization of the chloroform residue from aqueous methanol. The analytical sample, crystallized once more, has mp 219.0-220.6° [a][, 36° (acetone), reported mp 220° [aJu 38°. [Pg.94]

P,17P-Dihydroxyestr-4-en-3-one 1-acetate. The 6-hydroxy compound is removed from the column with 15-17% acetone. Recrystallization of the crude product (1.92 g) from acetone-hexane gives 1.25 g of crystals melting at 165-166° and 0.13 g melting at 162-164° (12.1% yield). When the analytical sample was prepared from the same solvent mixture, the melting point rose to 192-193° (Lit 166° 189-190°) [a] -59.5° (CHCI3) 2, 236 m/i (fi 14,500). [Pg.487]

A solution of 85.8 g (0.2 moles) of 3/ -acetoxy-27-norchoIest-5-en-25-one in 500 ml of anhydrous thiophen-free benzene is added to a Grignard solution prepared from 24.3 g (1 g-atom) of magnesium and 149 g (1.05 moles) of freshly distilled methyl iodide in 575 ml of anhydrous ether. The mixture is refluxed for 3 hr and allowed to stand overnight. After cooling to 5° the complex is decomposed by the slow addition of 200 ml of ice water and 400 ml of 50% acetic acid solution, and steam distilled until no more oil passes over. The residual product is filtered, washed with water and dried at 80°. Crystallization from methanol gives 70 g (87%) of cholest-5-ene-3)5,25-diol mp 179.5-181°. The analytical sample melts at 181.5-182.5° [a]o —39° (CHCI3). [Pg.71]

A total of 50 ml (0.15 moles) of a 3 ethereal solution of methylmagnesium bromide is added slowly to a vigorously stirred solution of 5.8 g (12.5 mmoles) or 3,3 20,20-bisethylenedioxy-5a,6a-epoxy-5a-pregnane-ll/l,17a,21-triol in 400 ml of tetrahydrofuran. The solution is heated under reflux for 24 hr, cooled and treated with 32 ml of saturated ammonium chloride solution. The supernatant is decanted and the residue is washed with several portions of tetrahydrofuran. The combined supernatants are evaporated and extracted with ethyl acetate, washed with saturated salt solution, dried and concentrated to give 4,55 g (75%) of 3,3 20,20-bisethylenedioxy-6 -methyl-5a-pregnane-5a,ll, 17a,21-tetrol mp 170-172° after crystallisation from acetone-petroleum ether. The analytical sample is crystallized from acetone-petroleum ether mp 175-177° [aJo —11° (CHCI3). [Pg.86]

A total of 3 g (0.13 moles) of sodium hydride is added to a solution consisting of 10 g of 17 -hydroxy-5a-androstan-3-one (36 mmoles) in 200 ml of benzene and 10 ml of ethyl formate. The reaction mixture is allowed to stand under nitrogen for 3 days followed by dropwise addition of 10 ml of methanol to decompose the excess of sodium hydride. The solution is then diluted with 300 ml water and the layers are separated. The basic aqueous solution is extracted with ether to remove neutral material. The aqueous layer is acidified with 80 ml of 3 A hydrochloric acid and the hydroxymethylene steroid is extracted with benzene and ether. The combined organic extracts are washed with water and saturated sodium chloride solution and then dried over magnesium sulfate and concentrated. The residue, a reddish-yellow oil, crystallized from 10 ml of ether to yield 9.12 g (83%) of 17 -hydroxy-2-hydroxymethylene-5a-androstan-3-one mp 162-162.5°. Recrystallization from chloroform-ether gives an analytical sample mp 165-165.5° [a]o 53° (ethanol) 2 ° 252 mjj. (g 11,500), 307 m u (e 5,800). [Pg.95]

The above nitrite (0.93 g) is dissolved in 40 ml of dry benzene and irradiated for 1 hr at 0-5° in a nitrogen atmosphere with two 200 Watt mercury lamps. The resulting suspension is concentrated and filtered to give 0.59 g of essentially pure 20a-hydroxy-18-oximinopregn-4-en-3-one as a benzene solvate mp 110-125°. Recrystallization from acetone gives an analytical sample mp 184-186° [a] 149° (CHCI3). [Pg.256]

Recrystallization from glacial acetic acid gives 4.6 g (90%) mp 225-227°. The analytical sample has mp 227-228°. [Pg.422]

A mixture of 4 g of diazoketone (94) and 2.2 g of sodium bicarbonate in 200 ml of tetrahydrofuran and 180 ml of water is irradiated with a Hanovia 200 W mercury vapor lamp (using a Corex filter) until the starting material has been consumed. After addition of 500 ml of water, followed by extraction of nonacidic products, the solution is acidified, cooled to 0° and filtered to yield 2.95 g (76%) of white crystals of crude acid (95) mp 170-176°. An analytical sample has mp 188°. ° ... [Pg.443]

Chloro-1 -methyl-5-phenyl-s-trizolo[4,3-a]quinoline A stirred mixture of 6triethyl-orthoacetate (0.925 g,0.0057 mol) and xylene (100 ml) was refluxed, under nitrogen, for 2 hours 40 minutes. During this period the ethanol formed in the reaction was removed by distillation through a short,glass helix-packed column. The mixture was concentrated to dryness In vacuo and the residue was crystallized from methanol-ethyl acetate to give 1.28 g of 7-chloro-1-methyl-5-phenyl-s-triazolo[4,3-a]-quinoline (83.9% yield). The analytical sample was crystallized from methylene chloride methanol and had a melting point 252.5°-253.5°C. [Pg.46]

Preparation of 1 -(/3-D-arabinofuranosyl)-2-thiocytosine A solution of 2.0 g of 1 -(2, 3, 5 -0-triacetyl-/3-D-arabinofuranosyl)-2,4-dithiouracil in 100 ml of methanol is saturated with anhydrous ammonia at 0°C. The mixture, in a glass liner, is heated in a pressure bomb at 100°C for three hours. The reaction mixture is concentrated to a gum in vacuo, and most of the byproduct acetamide is removed by sublimation at 60°C/0.1 mm. The residue is chromatographed on 100 g of silica gel. Elution of the column with methylene chloride-methanol mixtures with methanol concentrationsof 2-25% gives fractions containing acetamide and a series of brown gums. The desired product is eluted with 30% methanol-methylene chloride to give a total yield of 0.386 g (30%), MP 175°-180°C (dec.). Recrystallization from methanol-iso-propanol furnishes an analytical sample, MP 180°-182°C (dec.). [Pg.92]

The ether extract is evaporated to dryness to give about 500 mg of a crude product. From the ether solution there is obtained about 290 mg of yellow crystals, MP 220° to 236°C which is 17a,20,20,21-bis(methylenedioxy)-11 (3-formyloxy-2-hydroxy-methylene-6,16a-di-methyl-4,6-pregnadiene-3-one. The analytical sample is recrystallized from ethyl acetate and has a melting point of 249° to 255°C, [oIq -217°, I R 5.81 and 8.37 ji. From the mother liquor is obtained about 127 mg of 17a,20,20-21-bis(methylenedioxy)-11(3-hydroxy-2-hydroxymethylene-6,16a-dimethyl-4,6-pregnadiene-3-one. The analytical sample is recrystallized from ether and has a melting point of 200° to 204°C, [alo -197°, IR 6.05 to 6.2 and 6.4 jd. [Pg.391]

The above crude bromohydrin was mixed with 2.5 grams of potassium acetate and 60 cc of acetone and refluxed for 6 hours, at the end of which the acetone was distilled, water was added to the residue and the product was extracted with methylene chloride. The extract was washed with water, dried over anhydrous sodium sulfate and the solvent was evaporated. Recrystallization of the residue from methanol furnished 800 mg of the 16,21-diacetate of 6o-fluoro-9(3,11(3-oxido-A -pregnene-16o,l7a,2l-triol-3,20-dione with MP 120° to 124°C by chromatography of the mother liquors on silica gel there was obtained 180 milligrams more of the same compound with MP 117° to 119°C. The analytical sample was obtained by recrystallization from methanol it showed MP 125° to 127°C. [Pg.669]

The 1-(N-ethyl-N-2-hydroxyethylamino)-4-pentanone from above (284.2 grams) was dissolved in 300 grams of 28% ammoniacal methanol and reduced catalytically with Raney nickel (at an initial pressure of 1,000 pounds) at room temperature. After 24 hours the catalyst was filtered off and the product distilled in vacuo through a column, yielding 254 grams of a fraction distilling at 88.5° to 96°C at 0.3 mm and comprising mainly 5-(N-ethyl-N-2-hydroxyethylamino)-2-pentylamine. An analytical sample of this fraction distilled at 93°C at 0.6 mm. [Pg.784]

It is dissolved in hot methanol and heated on the steam bath with 10% methanolic potassium hydroxide solution (15.8 ml) for 10 minutes. Then more potassium hydroxide solution (2 ml) is added, the solution is cooled and on dilution with water a solid (II), MP 245° to 255°C, is obtained. A second crop is obtained from the mother liquors. Several recrystalli2ations from acetone yield an analytical sample, MP 262° to 265°C, [oIq is -2.1°. [Pg.912]

The above substance is dissolved in pyridine (15 ml) and acetic anhydride (7.5 ml), and heated on the steam bath for % hour. The product (lllb) crystalli2es from aqueous ethanol In leaflets, MP 237° to 239°C. An analytical sample has MP 241° to 243°C. [Pg.912]

A mixture of this material with 500 ml of toluene end 30 g of manganese dioxide wes heated to reflux for 1 A hours. The mangenese dioxide wes seperated by filtration over Celite. The filtrate wes evaporated and the residue was crystallized from ether to yield 6-chloro-6-(2-fluorophenyl)-1 -methyl-4H-imidazo[1,5-a] [1, 4] -benzodiazepine, melting point 152°C to 154°C. The analytical sample was racrystallized from methylene chloride/hexane. [Pg.1025]


See other pages where Sample analytical is mentioned: [Pg.105]    [Pg.306]    [Pg.80]    [Pg.221]    [Pg.98]    [Pg.413]    [Pg.416]    [Pg.447]    [Pg.448]    [Pg.472]    [Pg.473]    [Pg.473]    [Pg.486]    [Pg.487]    [Pg.488]    [Pg.488]    [Pg.97]    [Pg.411]    [Pg.421]    [Pg.422]    [Pg.426]    [Pg.216]    [Pg.364]    [Pg.22]    [Pg.47]    [Pg.47]    [Pg.47]    [Pg.669]    [Pg.669]    [Pg.670]    [Pg.1047]   
See also in sourсe #XX -- [ Pg.4 ]




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