Blood pH

Bioceuticals are supposed to be generally more biodegradable - but is this true even after denaturation, for example, in effluents of low or high pH Blood stains on textiles teach the opposite. 

You are doubtless familiar with the pH scale. On this scale, solutions with a pH less than 7 are acidic, and solutions greater than 7 are basic or alkaline. Solutions with a pH of exactly 7 are pH neutral, neither acidic nor basic. You know certain bodily fluids have characteristic pHs. Blood has a pH of 7.4. Stomach juice has a pH of around 1. What does the little p mean Why is 7 the midpoint How do we calculate pH ... 

Multiple-use quantitative, Electrochemistry. , pH, blood gases, electrolytes, metabolites... 

Ehrmeyer SS> Laessig RH. A computer model to translate federal proficiency testing performance standards for pH/blood gases into intralaboratory precision and accuracy requirements. In Methodology and clinical applications of blood gases, pH, electrolytes and sensor technology. 

International Federation of Clinical Chemistry, Committee on pH, Blood Gases and Electrolytes An Approved IFCC Recommendation. IFCC method (1988) for tonometry of blood Reference materials for PCO2 and PO2. Clin Chim Acta 1989 185 ... 

Burnett RW, Covington AK, Fogh-Anderson N, Kuipman WR, Maas AH, MuUer-Plathe, et al. Recommendations on whole blood sampling, transport, and storage for simultaneous determination of pH, blood gases, and electrolytes. J Int Fed Clin Chem 1994 6 115-20. 

Physiological factors, including expression of transporters, gastric emptying, gastrointestinal motility, intestinal pH, blood flow, lymph flow, and pathological state, must also be taken into account when evaluating absorption [13, 14]. 

Figure 2 - Effect of hemorrhage on muscle pH. Blood was withdrawn from this 12 kg. dog in 50 cc. aliquots represented by each arrow. Muscle pH decline preceded hypotension by 15 min. and began after the removal of 15% of estimated blood volume. Reinfusion of shed blood restored mean arterial pressure and muscle pH. The extent of peripheral vasoconstriction that caused the marked muscle acidosis was not evident from the minimal changes observed in arterial pH.

Jacobs E, Ancy JJ, Smith M (2002) Multi-site performance evahiatirai of pH, blood gas, electrolyte, glucose, and lactate determinations with the GEM Prtanier 3000 critical care analyzer. Point Care J Near-Patient Test Technol 1 135-144... 

This difference in behavior for acetic acid in pure water versus water buffered at pH = 7 0 has some important practical consequences Biochemists usually do not talk about acetic acid (or lactic acid or salicylic acid etc) They talk about acetate (and lac tate and salicylate) Why Its because biochemists are concerned with carboxylic acids as they exist in di lute aqueous solution at what is called biological pH Biological fluids are naturally buffered The pH of blood for example is maintained at 7 2 and at this pH carboxylic acids are almost entirely converted to their carboxylate anions... 

The concentration of the barbiturate barbital in a blood sample was determined by extracting 3.00 mL of the blood with 15 mL of CHCI3. The chloroform, which now contains the barbital, is then extracted with 10.0 mL of 0.045 M NaOH (pH = 13). A 3.00-mL sample of the aqueous extract is placed in a 1.00-cm cell, and an absorbance of 0.115 is measured. 

Immersion electrodes are the most common glass electrodes. These are roughly cylindrical and consist of a barrel or stem of inert glass that is sealed at the lower end to a tip, which is often hemispherical, of special pH-responsive glass. The tip is completely immersed in the solution during measurements. Miniature and microelectrodes are also used widely, particularly in physiological studies. Capillary electrodes permit the use of small samples and provide protection from exposure to air during the measurements, eg, for the determination of blood pH. This type of electrode may be provided with a water jacket for temperature control. 

Fouling of the pH sensor may occur in solutions containing surface-active constituents that coat the electrode surface and may result in sluggish response and drift of the pH reading. Prolonged measurements in blood, sludges, and various industrial process materials and wastes can cause such drift. Therefore, it is necessary to clean the membrane mechanically or chemically at intervals that are consistent with the magnitude of the effect and the precision of the results requited. 

Fig. 1. A multilayer coating dry chemistry test for blood urea nitrogen (BUN) where HI and I represent the acid base forms of a pH indicator, respectively...

Fig. 2. Homeostatic control of blood Ca " level where PTH is parathyroid hormone [9002-64-6], CC, cholecalciferol, ie, vitamin D HCC, hydroxycholecalciferol DHCC, dihydroxycholecalciferol CaBP, calcium-binding protein NAD PH, protonated nicotinarnide-adenine dinucleotide...

CycHc adenosine monophosphate (cAMP), produced from ATP, is involved in a large number of ceUular reactions including glycogenolysis, Hpolysis, active transport of amino acids, and synthesis of protein (40). Inorganic phosphate ions are involved in controlling the pH of blood (41). The principal anion of interceUular fluid is HP (Pig. 3) (41). 

Chromium(III) Chemistry. The most characteristic reactions of Cr(III) in aqueous solution at >4 pH, eg, in the intestine and blood, and hydrolysis and olation (147). As a consequence, inorganic polymeric molecules form that probably are not able to diffuse through membranes. This may be prevented by ligands capable of competing for coordination sites on Cr(III) (see Coordination compounds) (147). Thus any large fraction of ingested Cr(III) should be absorbed. Chromium (ITT) in the form of GTF may be more efficiendy absorbed. 

L-pyrenyldiazomethane to form stable, highly fluorescent L-pyrenyhnethyl monoesters (87). These esters have been analy2ed in human blood by ce combined with lif detection. To mimini e solute adsorption to the capillary wall, they were coated with polyacrjiamide, and hydroxypropyl methylceUulose and dimethylfoTTnamide were used as buffer additives to achieve reflable separations. Separation was performed in tris-citrate buffer, pH 6.4, under reversed polarity conditions. The assay was linear for semm MMA concentrations in the range of 0.1—200 p.mol/L. 

---