Reference

Study on tryptophan determination in feeds

Study on tryptophan determination in feeds. Ikumo, Haruhisa; Takigawa, Akihiro; Kameoka, Kenichi (Natl. Inst. Anim. Ind., Ibaraki 305, Japan). Nippon Chikusan Gakkaiho, 54(12), 788-93 (Japanese) 1983. CODEN: NICKA3. ISSN: 0369-4062. DOCUMENT TYPE: Journal CA Section: 17 (Food and Feed Chemistry) The detn. of L-tryptophan [73-22-3] in feeds was studied. Accurate detn. of tryptophan in feeds was made difficult by the required alkali hydrolysis of the sample. To prevent tryptophan degrdn. by alkali hydrolysis, 8 samples (feeds, lysozyme [9001-63-2], and egg albumin) weighing 10-500 mg were soaked in 5.0 mL of 5N NaOH soln. either with or without supplemental 250 mg L-histidine [71-00-1] and 500 mg Pb acetate [301-04-2]. The values of tryptophan contents detd. with supplemental L-histidine and Pb acetate were higher by ~20% av. than those detd. without supplementation. This increment was obsd. in all samples. Recovery of added L-tryptophan was 96.7% and 79.1% av. in supplemented and nonsupplemented samples, resp. The increased efficiency of recovery in the presence of supplements was also obsd. in all samples. Thus, loss of tryptophan during alkali hydrolysis of feeds could be prevented almost completely by histidine and Pb acetate supplementation (a modification of the method of J. R.In this experiment, several chemicals are used like 73-22-3 and 71-00-1 Spies and D. C. Chambers; 1949). .

Aspects of the chemistry of poly(ethylene terephthalate)

Aspects of the chemistry of poly(ethylene terephthalate). III. Transesterification of dimethyl terephthalate with ethylene glycol in the presence of various catalytic systems. Shah, T. H.; Bhatty, J. I.; Gamlen, G. A.; Dollimore, D. (Dep. Chem. Appl. Chem., Univ. Salford, Salford M5 4WT, UK). J. Macromol.Several substances with their cas registry numbers 107-21-1 and 7439-96-5 may be metioned in this study. Sci., Chem., A21(4), 445-57 (English) 1984. CODEN: JMCHBD. ISSN: 0022-233X. DOCUMENT TYPE: Journal CA Section: 35 (Chemistry of Synthetic High Polymers) The transesterification of di-Me terephthalate [120-61-6] with ethylene glycol [107-21-1] was studed by measuring the amt. of MeOH formed as a function of time. The influence of various catalytic systems was investigated with regard to the nature and concn. of the metal ion and the temp. The order of decreasing activity was Pb > Zn > Mn > Sn > Sb > Ti, and Zn(OAc)2 [557-34-6]-Pb acetate [301-04-2] and Zn(OAc)2-Sb2O3 mixts. were synergistic. A postulate that there is a correlation between the metal-O bond and the activity of the catalysts was discussed. .