Reagents, suppliers

Catalogues of Chemical Reagent Suppliers, (Aldrich, Sigma, Wako, Kanto). 

The history and chemistry of the hydroxy-oxime extractants which were originally developed for Cu recovery has been extensively reviewed.11,13,14 Szymanowski s book14 provides comprehensive cover of the literature prior to 1993 and assigns chemical structures to reagents which in most metallurgy texts are referred to only by codes provided by reagent suppliers. An updated version of this information is provided in Table 3. 

There is no full-scale U.S. commercial production of thiophosgene, but it is available in glass ampuls from laboratory reagent suppliers. Thiophosgene may be produced in Israel as an intermediate for tolnaftate (2-naphthyl A/-methyl-A/-w-tolylthiocarbamate) [2398-96-1], an antifungal drug. 

Synthesis. Benzenehexol is available only from laboratory reagent suppliers. The simplest laboratory preparation involves the aeration of the glyoxal—bisulfite addition product in sodium carbonate solution at 40—80°C, isolation of the sodium salt of tetrahydroxybenzoquinone, followed by acidification to obtain the free tetrahydroxy-p-benzoquinone in about 8% yield the latter is reduced with stannous chloride in boiling dilute hydrochloric acid solution to benzenehexol (77) in 77% yield (261). A similar procedure affords dipotassium rhodizonate (80) in good yield (262). 

Partly because of the complexity of the sample and problems relating to specificity, few standards are available. An expanding number of pertinent Standard Reference Materials is becoming available from the National Bureau of Standards. Even when available, cost dictates that these be used only to calibrate other reference materials. The latter include so-called standards purchased from reagent suppliers and control samples that are frequently derived from a carefully stored pool of blood samples. The precision of results can be assured by good instruments,... 

Nowadays, standard solutions may be obtained commercially from reagent suppliers. In addition to the pure aqueous standard solutions, standards made in varying matrices are also available. 

Labeling immunoenzyme conjugates Extensive publications describe methods to covalently link avidin or immunoglobulins to reporter enzymes. A wide range of bifunctional linkers are available commercially. Prepared, stabilized conjugates are available from immunological reagent suppliers. 

We advance several reasons for discussing the deceptively simple synthesis of ILBSs and their parent ILs a search in the catalog of a major chemical reagents supplier has shown that only a very few ILBSs are commercialized. If the purities in these surfactants are similar to those of the structurally related ILs, commercialized by the same supplier, then this purity is not satisfactory, because 81% have purity less than or equal to 98% (Fig. 4.2). Note that surface-active purity ... 

Protected nucleosides and nucleoside-3 -succinates are commercially available from a variety of biochemical reagent suppliers (i.e., Sigma Chemical Co., St. Louis, MO, or Penninsula Laboratories, Inc., Belmont, CA), or they may be prepared by following published procedures (2). 

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