L-Cysteine ​​CAS 52-90-4 (H-Cys-OH) Assay 98.5 ~ 101.0% (Titration) Hoobkas High Quality

L-Cysteine ​​muaj tsis pub tsawg dua 98.5% thiab tsis pub ntau tshaj 101.0% ntawm L-Cysteine ​​(C3H7NO2S), suav ntawm lub hauv paus qhuav.
Kev piav qhia L-Cysteine ​​tshwm sim raws li cov muaju dawb los yog cov hmoov dawb crystalline.Nws muaj ib tug yam ntxwv tsw thiab ib tug pungent saj.Nws yog dawb do soluble nyob rau hauv dej, thiab xyaum insoluble nyob rau hauv ethanol (99.5).Nws yaj hauv 1 mol / L hydrochloric acid TS.
Kev txheeb xyuas Kev txiav txim siab qhov infrared absorption spectrum ntawm L-Cysteine ​​raws li qhia nyob rau hauv cov poov tshuaj bromide disk txoj kev nyob rau hauv Infrared Spectrophotometry <2.25>, thiab muab piv cov spectrum nrog rau Reference Spectrum: ob qho tib si spectra qhia zoo sib xws ntawm kev nqus ntawm tib yoj tus lej.
Kev sib hloov kho qhov muag <2.49> [a]20D: + 8.0 ~ + 10.0 ° (2 g suav ntawm lub hauv paus qhuav, 1 mol / L hydrochloric acid TS, 25mL, 100 mm).
pH <2.54> Cov pH ntawm cov tshuaj npaj los ntawm dissolving 1.25 g ntawm L-Cysteine ​​nyob rau hauv 50 mL dej yog 4.7 mus rau 5.7.
Purity (1) Clarity thiab xim ntawm cov tshuaj - Dissolve 1.0 g ntawm L-Cysteine ​​nyob rau hauv 20 mL dej: cov tshuaj yog ntshiab thiab tsis muaj xim.
(2) Chloride <1.03>- Dissolve 0.30 g ntawm L-Cysteine ​​nyob rau hauv 10mL ntawm diluted nitric acid (1 nyob rau hauv 4), ntxiv 10mL ntawm hydrogenperoxide (30), tshav kub rau 20 feeb nyob rau hauv boiling dej da dej, txias, thiab ces ntxiv. dej los ua 50 mL.Ua qhov kev sim siv qhov kev daws teeb meem no raws li qhov kev sim tshuaj.Npaj cov tshuaj tswj nrog 0.35 mL ntawm 0.01 mol / L hydrochloric acid VS (tsis ntau tshaj 0.041%)
(3) Sulfate <1.14>- Dissolve 0.6 g ntawm L-Cysteine ​​nyob rau hauv 30 mL dej thiab 3 mL ntawm dilute hydrochloric acid, thiab ntxiv dej kom 50 mL.Ua qhov kev sim siv qhov kev daws teeb meem no raws li qhov kev sim tshuaj.Npaj cov tshuaj raws li nram no: Rau 0.35 mL ntawm 0.005 mol / L sulfuric acid VS ntxiv 3 mL ntawm dilute hydrochloric acid thiab dej kom 50 mL.Npaj cov tshuaj ntsuam xyuas thiab kev tswj cov tshuaj nrog 4 mL ntawm barium chloride TS, feem (tsis ntau tshaj 0.028%).
(4) Ammonium <1.02>-Ua qhov kev sim nrog 0.25 g ntawm L-Cysteine, siv cov distillation nyob rau hauv lub siab txo.Npaj cov tshuaj tswj nrog 5.0 mL ntawm Standard Ammonium Solution (tsis ntau tshaj 0.02%).
(5) Cov Hlau Hnyav <1.07>-Tom ntej nrog 1.0g ntawm L-Cysteine ​​raws li Txoj Kev 4, thiab ua qhov kev sim.Npaj cov tshuaj tswj nrog 1.0 mL ntawm Standard Lead Solution (tsis ntau tshaj 10 ppm).
(6) Hlau <1.10>-Npaj cov tshuaj ntsuam xyuas nrog 1.0 g ntawm L-Cysteine ​​raws li Txoj Kev 1, thiab ua qhov kev sim raws li Txoj Kev A. Npaj cov tshuaj tswj nrog 1.0mL ntawm Standard Iron Solution (tsis ntau tshaj 10 ppm. ).
(7) Cov Khoom Siv - Dissolve 0.10 g ntawm L-Cysteine ​​nyob rau hauv N-ethylmaleimide tov (1 hauv 50) kom ua raws nraim 10 mL, tawm rau 30 feeb, thiab siv cov tshuaj no ua cov qauv tshuaj.Pipet 1 mL ntawm cov qauv tov, ntxiv dej kom raws nraim 10 mL, pipet 1 mL ntawm cov tshuaj no, ntxiv dej kom raws nraim 50 mL, thiab siv cov tshuaj no raws li tus qauv tov (1).Cais, yaj 0.10 g ntawm L-cystine hauv 0.5mol / L hydrochloric acid TS kom ua raws nraim 20 mL.Pipet 1mL ntawm cov tshuaj no, ntxiv dej los ua 100 mL, thiab siv cov tshuaj no raws li tus qauv tov (2).Ua qhov kev sim nrog cov kev daws teeb meem no raws li qhia hauv Thin-txheej Chromatography <2.03>.Spot 10mL txhua tus qauv kev daws teeb meem thiab cov qauv kev daws teeb meem (1) thiab (2) ntawm lub phaj ntawm silica gel rau nyias txheej chromatography.Txhim kho lub phaj nrog sib tov ntawm 1-butanol, dej, thiab acetic acid (100) (3: 1: 1) mus rau qhov deb li ntawm 10 cm, thiab qhuav lub phaj rau 30 feeb ntawm 809C.Txau lub phaj sib npaug nrog cov tshuaj tov. ntawm ninhydrin nyob rau hauv ib tug sib tov ntawm methanol thiab acetic acid (100) (97:3) (1 nyob rau hauv 100), thiab ces tshav kub ntawm 80 ℃ rau 10 feeb: qhov chaw tau los ntawm cov qauv tov sib haum mus rau qhov chaw tau los ntawm cov txheej txheem tov. (2) tsis txhob khaus ntau tshaj qhov chaw los ntawm cov txheej txheem daws teeb meem (2).Tsis tas li ntawd, qhov chaw uas tsis yog qhov chaw tseem ceeb thiab cov chaw hais saum toj no los ntawm cov qauv kev daws teeb meem tsis yog khaus ntau dua li qhov chaw los ntawm cov txheej txheem daws teeb meem (1).
Poob rau ziab <2.41> Tsis pub ntau tshaj 0.50% (1 g, hauv lub tshuab nqus tsev, phosphorus (V) oxide, 3 teev).
Residue ntawm Ignition <2.44> Tsis ntau tshaj 0.1% (1 g).
Assay Weigh kom meej txog 0.2 g ntawm L-Cysteine, muab tso rau hauv lub khob ntim dej, thiab yaj hauv 20 mL dej.Dissolve 4 g ntawm poov tshuaj iodide nyob rau hauv cov tshuaj no, tam sim ntawd muab tso rau hauv dej txias, ntxiv 5 mL ntawm dilute hydrochloric acid thiab raws nraim 25 mL ntawm 0.05 mol / L iodine VS, tawm hauv qhov chaw tsaus rau 20 feeb, thiab ces titrate <2.50. > ib qho nyiaj ntau ntawm iodine nrog 0.1 mol / L sodium thiosulfate VS (qhov taw qhia: starch TS).Ua ib qho kev txiav txim siab dawb paug siv tib txoj kev.
Txhua mL ntawm 0.05 mol / L iodine VS＝12.12 mg ntawm C3H7NO2S
Containers thiab Storage Containers-Tight containers.