Acidic deproteination

In each of these methods, undiluted serum, urine, acid-deproteinized milk, or a buffered saline extract of muscle was mixed with sulfamethazine-horseradish peroxidase and added to antibody-coated wells of a microtiter plate. A sulfamethazine-bovine serum albumin conjugate prepared by the glutaraldehyde procedure (56) was used for antibody production. Results showed that screening of serum was of value since sulfamethazine concentrations in serum directly correlated with those in swine tissues. Thus, for example, a level of 100 ppb of sulfamethazine in... 

T Flirai, H Ohyama, R Kido. A direct determination of taurine in perchloric acid-deproteinized biological samples. Anal Biochem 163 339-342, 1987. 

Stewart et al. (S8) estimated magnesium in serum and urine. Of four different methods of sample preparation (i.e., wet-ashing, deproteiniza-tion, simple dilution with water, and dilution with hydrochloric acid), deproteinization with trichloroacetic acid was found to be most satisfactory. No interference was seen from sodium, potassium, or phosphate, but sulfate produced depression. With protein a 6% decrease in the apparent magnesium concentration was seen. Calcium and sulfate were added to standards and samples to control sulfate depression. 

This method was developed by Stoeppler et al. (1978). It has the advantage of a simple and fast sample pretreatment. Since lead is determined in an acidic aqueous solution obtained from blood by acid deproteinization, the matrix influences are relatively low and there are practically no salt residues left in the graphite tube. The method. 

Vitamin B5 occurs in three biologically active forms in foods [1] pantothenic acid, coenzyme A (CoA), and acyl carrier protein (ACP). Calcium or sodium pantothenate are the forms generally used as supplements in infant formula [4], The total quantification of vitamin B5 requires the release of pantothenic acid from CoA and ACR Since it consists of pantoic acid linked through an amide linkage to p-alanine, chemical hydrolysis cannot be used. The only alternative to free pantothenic acid from CoA is the digestion with a number of enzymes (pepsin, alkaline phosphatase, pantetheinase) nevertheless, this treatment is unable to release the vitamin from ACP [27,28]. For the extraction of free pantothenic acid from milk and calcium pantothenate from infant formula an acidic deproteination is often used, followed by centrifugation and filtration [29,30]. 

The optimized method was used for the analysis of ovine, caprine and bovine milk, in the last case in either skimmed, semi-skimmed and full-cream milk, after suitable acidic deproteination followed by a sohd phase extraction procedure. 

With gently hemolyzed chicken erythrocytes PROTO synthesis from glycine is markedly depressed but may be restored partially by the addition of various cofactors (35). For example, 80% of the activity may be restored by the addition of glycine, pyridoxal-P, and an acid-deproteinized pig liver fraction the synthesis may then continue over a period of 15 hr. 

A polymethacrylate copolymer is modified by successive reaction with epichlorohydrin, w-aminophenylboric acid, and nitric acid to introduce a 1-amino-(2 -nitrophenyl-5 -boric acid)-2-hydroxyl-3-o-propyl group. The modified polymethacrylates are used as chromatographic support materials and can be used to analyze biological materials without prior deproteinization (35). 

Polymer Labs. PLRP-S 0.01M oxalic acid-ACN (75 25, v/v) UV 360 nm Animal tissues Extraction with oxalic buffer followed by chelation and deproteination, cleanup with styrene-divinylbenzene cartridge Rec 76-87% [77]... 

Rabenstein and Yamashita [52] determined penicillamine and its symmetrical and mixed disulfides by HPLC in biological fluids. Plasma and urine were deproteinized with trichloroacetic acid, and HPLC was performed on a column (25 cm x 4.6 mm) or Biophase ODS (5 pm) with a mobile phase comprising 0.1 M phosphate buffer (pH 3) and 0.34 mM Na octylsulfate at 1 mL/min. Detection was with a dual Hg-Au amalgam electrode versus a Ag-AgCl reference electrode. (z>)-penicillamine and homocysteine were determined at the downstream electrode at +0.15 V, and homocystine, penicillamine-homocysteine, and penicillamine disulfides were first reduced... 

Shaw et al. [64] described a (D)-penicillamine detection method in blood samples that had been treated with EDTA, deproteinized with trichloroacetic acid, and analyzed within 1 h. Penicillamine was detected at a vitreous-carbon electrode operated at +800 mV after HPLC separation. A linear calibration graph was obtained, and the method had a limit of detection equal to 5-20 ng. The method was useful in clinical and in pharmacokinetic studies. 

A competitive fluorescence-polarization immunoassay method was described for the monitoring of 12 drugs including valproic acid [18]. Samples (serum or plasma) were deproteinated. Fluorescence from the fluorescein-labeled analyte used as tracer was excited at 488 nm and polarization of light emitted at 531 nm was measured. The calibration was stable for 4 weeks and the coefficient of variation was below 10%. A single measurement took 8-10 min. 

More recent determinations of serum iron have been reported by Schmidt 57), who simply diluted with lanthanum chloride solution, and by Tavenier and Hellen-doorn58), who deproteinized samples in the latter study, iron in the protein precipitate is analyzed to correct the serum iron level. Uny etal. 59) determined serum iron, using ultrasonic nebulization of the sample to increase the sensitivity. Olson and Hamlin 6°) have determined serum iron and total iron-binding capacity. Proteins are precipitated and iron (III) is released by heating with trichloroacetic acid. 

There is a great deal of interest in the determination of lead, particularly micromethods applicable to the analysis blood lead in children. Consequently, reports continue to appear on the atomic absorption determination of lead in blood and urine. Ninety percent of blood lead is found in the erythrocytes and, therefore, whole blood is analyzed rather than serum or plasma. Berman etal. 134) have described a procedure for determining normal lead levels in which only 250 fd of blood are taken. The blood is deproteinized with 1 ml of 10 % trichloroacetic acid and then the lead is extracted with APDC into 1 ml of MIBK, at pH 3.5. 

Blood should be deproteinized by some technique which leaves no extra salt, acid, or alkali in the supernatant Some suitable techniques are with tungstic acid, with ethanol (BIO), or with zinc sulphate and barium hydroxide (S21). The supernatant is desalted in the same way as urine and, if necessary, concentrated before applying to the paper. Subsequent technique is as for urine. 

The first fractionation of urinary ampholytes in this way was carried out by Boulanger et al. (BIO) in 1952 with the use of ion-exchange resins. They had designed this procedure previously for the fractionation of ampholytes in blood serum (B8). According to this method, deproteinized urine was subjected to a double initial procedure aiming at the separation of low-molecular weight substances from macro-molecular ones. One of the methods consisted of the fractionation of urinary constituents by means of dialysis, the second was based on the selective precipitation of urinary ampholytes with cadmium hydroxide, which, as had previously been demonstrated, permits separation of the bulk of amino acids from polypeptides precipitated under these circumstances. Three fractions, i.e., the undialyzable part of urine, the dialyzed fraction, and the so-called cadmium precipitate were analyzed subsequently. 

Plasma Deproteinization with trichloroacetic acid bromination of supernatant and treatment with pyridine-p-phenylene diamine Spectrophotometry (thiocyanate- cyanide determination) 0.07 ppm 96 (thiocyanate) Pettigrew and Fell 1972... 

Deproteinization with 5% acetic acid in ACN, defatting with n-hexane, SPE C18, 25% 1 M aq. Ammonia in MeOH elution... 

Dairy Dilution with 0.3 N oxalic acid solution and deproteinization with TCA Extrasyl ODS-2 S5 (25x0.40cm, 5pm) NaOAc buffer 0.08 M UV, DAD [84]... 

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