Phosphate washing

A better method has been described by Schwarz (S6). Washed red blood cells are lysed, precipitated with trichloroacetic acid below 0°C and the supernatant quickly neutralized. Speed and low temperatures are necessary to prevent hydrolysis of galactose-l-phosphate which is very sensitive to acid. Barium acetate and ethanol are added, and the precipitated barium salt of galactose-l-phosphate washed with 80% ethanol. The barium salt is then hydrolyzed by heating with dilute hydrochloric acid, acid and salts removed with mixed ion-exchange resins, and the galactose estimated by paper chromatography as described above. It is probably better to avoid the Amberlite MB-1 resin used by Schwarz and, instead, to use a weak base resin mixture, such as Amberlite MB-4. Recovery of added galactose-l-phosphate should be determined simultaneously. 

The synthesis of the photoaffinity probe, NAZA-FL, lc, will be described elsewhere. The effects of this acyclic modifier on mitochondrial activities were assayed as previously described (5,6). The results are summarized in the Table. The effects, and the effective concentration range, of compounds lc and La are similar in the dark. With the photolabile modifier,< T(c, illumination with strong light resulted in an irreversible preferential inhibition of the energy-dependent proton movements this effect was not relieved by phosphatidylcholine vesicles. Hence, the modifier became covalently bonded in the vicinity of its implantation. Additional experiments were performed with phosphate-washed (12) membrane preparations (ATPase-enriched inner membrane frac-... 

Analogous experiments were performed with PCP. In these experiments, hair from a PCP drug user was exposed to a solution of p-methylPCP at a concentration of 1 pg/mL for 1 h. The final extract contained 2.3 ng of PCP/mg of hair, whereas p-methylPCP was found at a concentration of 12 ng/mg of hair. More of the drug surrogate was found in the hair than the PCP incorporated in vivo. Neither the extraction kinetics nor the ratio of PCP in hair to that of the last phosphate wash clearly distinguished this hair specimen as contaminated by p-methylPCP. 

The uptake of cocaine to hair after preliminary exposure to various acidic and basic solutions is shown in Figure 10. Three sets of experiments were performed. In the first experiment, hair was exposed to base (0.1 M sodium carbonate, pH 12) for 3 h and then washed extensively with water rmtil the water was neutral. This was then followed by two phosphate buffer rinses at pH 5.3 for 10-min periods. The hair was then exposed to 5 pg/mL of cocaine, containing a radioactive tracer, in phosphate buffer at pH 5.3 for 1 h. After exposure the excess cocaine was removed with three water rinses of 10 min each and the hair was dried. Then the hair was decontaminated with ethanol and six phosphate washes, digested, and the cocaine concentration determined by scintillation counting as per previously described procedures. Approximately twice as much cocaine was incorporated into the hair pretreated by exposure to base as compared to hair not subjected to any pretreatment. In the second experiment, hair was pretreated with 0.1 M HCl, then treated as in the first experiment. In this case approximately one sixth as much cocaine was incorporated as the control. In the third experiment, hair was pretreated with 5% acetic add and treated as in the... 

Baumgartner and Hill s decontamination procedure was evaluated on more than 500 different hair samples that were externally contaminated in this laboratory. In the initial phases of this study we used four phosphate washes. In later phases, based upon the comments in Baumgartner and Hill, ° our procedure was modified to use between three and ten phosphate washes. However, in the radioactive tracer experiments we typically perform, it is possible to account for all radioactivity the sample is digested and no radioactivity is lost from any extraction step. Therefore, it is possible to calculate the effect of either three or four phosphate washes on the decontamination of the hair and on the various calculated criteria. No remarkable differences were found between our four-phosphate extraction process and the recalculated values for the equivalent three-phosphate extraction process. 

Inorganic contaminants are immobilized by washing the waste with soluble phosphates. This treatment uses a very small amount of phosphate, does not change other characteristics of the waste such as its granular nature or volume, and is relatively inexpensive. If the waste contains radioactive contaminants, phosphate washing is not sufficient because the dispersibility of the radioactive contaminant powders needs to be reduced, and hence, the waste needs to be solidified. Solidification requires generating phosphate ceramics of the waste in the form of a CBPC. In the case of radioactive waste, both stabilization and solidification are needed because they not only immobilize the contaminants, but also solidify the entire waste. As we will see in this and the next chapter, whether phosphate treatment is used only for stabilization or for both stabilization and solidification, it is very effective for a wide range of waste streams. 

The overall phosphate stabilization of hazardous waste streams may be put in two categories simple phosphate washing to stabilize most of the contaminants and actual formation of a CBPC waste to treat more difficult contaminants. These two approaches are described below. 

Phosphate washing has been in use for many years. Over a decade ago, Wheelabrator Technologies [8,9] patented a process to treat waste incineration residue ashes from... 

In the phosphate washing discussed above, only a small amount of acid phosphate is used to convert contaminants into their insoluble phosphate forms. To fabricate CBPC waste forms, however, a larger amount of binder is needed, so compared to the phosphate washing, the cost of the binder is high. This condition does not mean that the volume of the stabilized waste will increase. Typically, the washed waste is loosely packed, but the fully stabilized ceramic matrix is dense. As a result, the volume does not increase and, hence, the disposal cost will remain the same. Depending on the nature of the waste and amount of the phosphate binder used, the binder cost may be the only higher cost in the CBPC treatment compared to simple acid washing. 

The examples given above and the work done in the last 10 years on phosphate washing demonstrate that phosphates are very powerful stabilizers of inorganic hazardous contaminants. Phosphate washing is very economical, and once the treated waste is disposed, because phosphates are common fertilizer components, the soil becomes enriched with phosphates. Hence, the entire disposal process is ecologically sound. 

Prepare the gel by mixing 500 ml of 1 M calcium chloride and 500 ml of IM dibasic sodium phosphate. Wash the gel on a glass filter with 1000 ml of ice-cold water and then suspend in 500 ml of... 

A reactivation of an inactive nitrate reductase apoenzyme extracted from molybdenum-deficient plants can be achieved by the addition of acid-treated nitrate reductase or by addition of phosphate buffer washes of nitrate reductase absorbed on AMP-Sepharose. The acid treatment or phosphate wash apparently produced a molybdenum-containing complex which was responsible for reactivation of the apoenzyme. The complex had a molecular weight of less than 3 x 10 (Notton and Hewitt, 1971 Rucklidgee/< /., 1976). These reports clearly demonstrate the requirement for molybdenum for nitrate reduction however, the role of the metal in the reduction process is not completely resolved. 

In 1803, Thenard showed that by calcining a mixture of aluminium hydrate with acetified cohalt phosphate or acetified cobalt arsenate one could more easily produce the pigment than with mixtures of cobalt carbonate or cobalt nitrate. Cobalt nitrate solutions would be precipitated with the acetified sodium phosphate, the purple cobalt phosphate washed with water and mixed with eight times the weight of alumina hydrate which had been precipitated with ammonia. Afterwards this mixture would be brushed onto boards for drying when it became solid and brittle it would be ground and calcined in a closed clay container for half an hour. 

Codeine phosphate. Wash the column with 100 ml of water and elute the codeine to volume into a 100-ml graduated fiask with N hydrochloric acid at a flow rate of 3-5 ml per minute. Measure the extinction E) of a 1-cm layer at the maximum at about 285 mp using N hydrochloric acid as reference. 

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