Acidified urine

Although it has not been proven that acidification of the urine to increase PCP excretion alters the duration of the symptoms of psychosis, it appears appropriate to facilitate excretion of PCP from the adipose tissue in which it is stored in any PCP user (Done 1980). Maintaining the urine pH at an acid level for several weeks, even though the mental status is normal, is advised. It is important to test the pH of the urine to ensure compliance with the acidification. We have found that PCP becomes detectable in acidified urine for a time, even after being undetectable in alkaline urine, in previously intoxicated individuals. We have not found a change in mental status to result from such acidification treatment and resultant enhanced PCP excretion. 

Several investigators have described the indirect determination of orthophosphate by extraction of the phosphomolybdic acid complex and the measuring the molybdenum extracted. Zaugg and Knox 2921 first applied this technique to the determination of phosphate in urine. A protein-free filtrate was formed and the complex was extracted into 2-octanol. More recently, Devoto 293) determined 0 to 25 pg of phosphate in 50 ml of urine by extracting the complex from acidified urine into isobutyl acetate. 

Acidosis induced by salt feeding to humans influenced urinary calcium loss as effectively as feeding whole foods. Martin and Jones (25), for example, fed adult subjects a diet supplemented with ammonium chloride which resulted in marked hypercalciuria and an acidified urine. In a follow-up trial, feeding alkali as sodium bicarbonate, they also demonstrated that human hypercalciuria could be prevented by adding an alkaline supplement to the diet. 

Fio. 60. Chromatogram of acidified urine extract. Column 5>/ m octadecyl silica, 25 cm X 4.6 mm i.d., temperature, 70 C flowrate, 2.0 ml/min. Gradient elution from 0.1 M phosphaM buffer, pH 2.1, with acetonitrile to about 4096 (v/v) organic solvent concentration. Sample size 10 containing the extract of 100 of urine. Reprinted with permission from Horvath et al. (3S4). 

Ascorbic acid may acidify urine, leading to crystalluria. 

Keep urine acidic (pH <5.5) by eating food that acidifies urine (meats, eggs, fish, gelatin products, prunes, plums, cranberries) may need to add ascorbic acid... 

It is indicated for treatment of scurvy, for prophylaxis of vitamin C deficiency, to acidify urine, anaemia of vitamin C deficiency, as antioxidant to protect natural colour and flavour of many foods, dental caries and increased capillary fragility. 

Alternatively, acidified urine can be collected on a filter paper. The urine is preserved with 20% HC1 as described above. Filter paper strips (3 x 5 cm filter paper backing, cat. No. 165-0921, Bio-Rad) are dipped into urine to 1 cm below the upper edge. Excess urine is wiped off, and the filter is left to dry at room temperature. Urinary filter paper spots are then cut into small pieces, shaken in 3 ml of water for 15 min at room temperature, and sonicated for 5 min at room temperature. The extracts are filtered through an Ultrafree-MC filter with 10-kDa cutoff (Millipore, USA) at 2000g for 10 min at room temperature. The clear supernatant is analyzed by HPIC. 

The metabolism of amphetamine has been studied in those presenting with amphetamine psychosis. In the presence of acidified urine, the renal elimination of amphetamine increased significantly. The intensity of the psychosis was found to correlate with the amount of basic polar metabolites excreted in the urine, such as norephedrine and p-hydroxyamphetamine, and not with the plasma amphetamine concentration. This suggests that these metabolites may play an important role in the development of paranoid psychosis in chronic amphetamine users.6... 

Of the common alkyl polyamines, ethylenediamine is the most notable because of its widespread use and toxicity. Although it has a toxicity rating of only three, it can be very damaging to the eyes and is a strong skin sensitizer. The dihydrochloride and dihydroiodide salts have some uses as human and veterinary pharmaceuticals. The former is administered to acidify urine, and the latter as an iodine source. Putrescine is a notoriously odorous naturally occurring substance produced by bacteria in decaying flesh. 

Exposure to toluene can be detected by extracting hippuric acid from acidified urine into diethyl ether or isopropanol and direct ultraviolet absorbance measurement of the extracted acid at 230 nm. When the analysis is designed to detect xylenes, ethylbenzene, and related compounds, several metabolites related to hippuric acid may be formed and the ultraviolet spectrometric method does not give the required specificity. However, the various acids produced from these compounds can be extracted from acidified urine into ethyl acetate, derivatized to produce volatile species, and quantified by gas chromatography. 

An HPLC method to determine etodolac enantiomers and their major metabolites in urine, using a bovine serum albumin stationary phase, has been developed [13]. After extraction of etodolac from acidified urine with cyclohexane / ethyl acetate (95 5, v/v), the organic layer was separated, evaporated, and reconstituted in 2-propanol. The samples were injected onto a 125 x 4 mm i.d. (10 pm particles) column. The mobile phase used was 0.05 M pH 4 phosphate buffer / 2-propanol (98 2, v/v) at a flow rate of 1.2 mL/min. Detection was effected at 230 nm using a UV detector. The (5)-(+)-etodolac enantiomer eluted before the (/ )-(-)-enantiomer. The enantiomeric analysis of various metabolites of etodolac was also described. 

It is used in the treatment of scurvy, postoperative cases, and healing bedsores and chronic leg ulcers. Vitamin C increases the absorption of iron during anemia and is frequently combined with ferrous salts. It is used in urinary tract infections to acidify urine. Large doses of vitamin C have been tried to cure everything from the common cold to cancer, with not much success. The usefulness of vitamin C in asthma, cancer, atherosclerosis, psychologic symptoms, and fertility is doubtful. Ascorbic acid is well tolerated in large doses and may cause rebound scurvy on withdrawal. There is a possibility of forming urinary stones. 

LC/MS/MS is an important technique for the analysis of free metabolites and covalent adducts of sulfur mustard in urine and blood. In the case of TDG and TDGO, LC/MS has not yet been able to achieve the LODs obtainable with GC/MS after derivatization. LC/MS/MS has, however, been used successfully to analyze the metabolites (20, 21) derived from an initial reaction of sulfur mustard with glutathione (see Chapter 16). The two metabolites (20), derived from the 3-lyase pathway, can be isolated from urine by SPE on a hydroxylated polystyrene-divinylbenzene polymeric cartridge. Using a sensitive triple sector quadrupole LC/MS/MS system, detection limits of O.lng/ml have been achieved using positive ESI and MRM (56). This provides a useful alternative to GC/MS/MS, which requires reduction of the sulfoxide functions with titanium trichloride. An LC/MS/MS method (detection limit lng/ml) has been developed for the analysis of the hisf N - ace ly I cysteine) metabolite (21) in urine (57). Concentration from acidified urine was achieved on... 

Attempts to develop a GC/MS method for this metabolite were unsuccessful, no doubt because of thermal instability. An LC/MS/MS method using thermospray ionization, after derivatization to the dimethyl ester, gave a modest detection limit of 25 ng/ml, again probably due to poor thermal stability, in this case, in the thermospray ion source (12). A substantial improvement has recently been achieved (detection limit 1 ng/ml) using LC/ESI/MS/MS without derivatization (31). Concentration from acidified urine was achieved on... 

The drug which is a weak base is more ionized in acidified urine and less able to be reabsorbed. Uncharged molecules have a greater solubility in the lipid bilayer of membranes, and thus more readily cross membranes. 

Urine. As previously mentioned, the term albumin derives from the white precipitate resulting from boiling acidified urine. The sulfosalicyhc acid heat test is still used today to test for albuminuria however, screening is usually... 

Methods for porphyrin fractionation are complex and time consuming and not available in every laboratory. For this reason, simple qualitative screening tests are often used to exclude the majority of specimens that do not require further investigation from the few that justify fractionation of the individual porphyrins. Screening tests in which extracts of urine or feces are examined visually for typical red-pink fluorescence of porphyrins lack sensitivity and should not be used. Methods based on spectrophoto-metric scanning of acidified urine or fecal extracts for the presence of the Soret band are recommended and yield semiquantitative information. Quantitative fluorometric methods are also available. ... 

Figure 32-3 Absorption spectrum of acidified urine showing the procedure for the measurement of corrected absorbance (A) of the porphyrin peak.

Some patients acidify urine at a submaximal rate, but at a rate that is generally sufficient to maintain acid-base balance. Potassium wasting, hypokalemia, and hyperchloremia are generally not present. However, when patients are stressed or are given an acid load, their ability to excrete acid and to lower urine pH is suboptimal and urinary pH may exceed 5.5. 

Beckett and Triggs were interested in the determination of nicotine and its main metabolite cotinine in urine. An acidified urine was extracted with diethyl ether to remove impurities, the urine was made alkaline with sodium hydroxide and the nicotine extracted with diethyl ether. Cotinine was extracted from urine with methylene chloride after basification of the sample with ammonia. On concentration of the solution, the gas chromatography was carried out on a packed column treated with KOH using Carbowax 20 M as stationary phase. A relative recovery of 95-100 % for the two alkaloids was obtained with respect to their internal standard, chlorophentermine for nicotine and lignocaine for cotinine, which were added to the urine at the start of the assay procedure. Typical chromatograms are given in Figure 4. 

Urine (TTCA) Acidify urine sample, extract with ether and evaporate dissolve residue in methanol and analyze HPLC 82 ng/L NR Campbell et al. 1985... 

Water, urine, mussel tissue, SRMs/CRMs Co Waters filter and acidify urine and mussel digest with HNO3/ HCl (bomb) [N/MT WDC] Direct solution by FI to on-line column preconcentration system, inject into transversely heated GFA (THGA), [FTAAS] [N/MT-SEP/ CONC-EAAS WDC-SEP/CONC- ETAAS] Anthemidis et al. (2002)... 

Arsenic, copper, antimony, chromium, mercury, selenium and zinc were concentrated in the precipitate upon storage of acidified urine for 2 days, whereas manganese, cobalt, caesium and rubidium remained in the supernatant fraction (Cornelis et al., 1975). 

The procedure started with acidified urine (1 ml HCI to 100 mL of urine) and used a commercially available mercury/hydride system (MHS-10, Perkin Elmer) attached to a Perkin-Elmer 360 AAS instrument with EDL (resonance line at 193.8 nm). The peak area measurements and peak recording were performed with a single-channel integrating recorder. 

The GC/MS-MS methods for the quantitative determination of nerve agents have been reported (Driskell ct al 2002 Barr etal., 2004). The difference between the two methods is that in the study by Driskell etal., the urine sample.s were concentrated by forming an azeotrope with acetonitrile, whereas in the study by Barr et al the acidified urine samples were extracted into ether acetonitrile. The samples were derivalized by methylalion with diazomeihane and analyzed by GC/MS-MS. 

---