Biological Material deproteination

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). 

While flame AAS is adequate for routine determination of serum Fe, micro methods utilizing the furnace have been developed (Lewis et al., 1984) for pediatrics, etc. Of course, deproteinization is still required, usually with trichloroacetic acid. Because of furnace sensitivity, the serum sample is diluted 1 -i- 9 in a solution containing the matrix modifier and about 0.2% Triton X-100, and a 10-/other biological materials, once the sample is in solution. 

Cholak et al. (C5) determined 0.05-20 /xg of lead in biological materials by extraction with APCD and MIBK at pH 8.5. Potassium cyanide was added to mask the effects of iron, zinc, and copper. Only bismuth and cadmium were found to interfere under these eonditions. Mishima et al. (M4) deproteinized 5 ml of blood with 10 ml of 5% TCA and extracted the lead with I ml of 1% APCD and 5 ml of MIBK. Marumo et al. (M2) overcame a reported interference from greater than 220 /xg iron in blood by extracting the iron with cupferron into MIBK prior to extraction of the lead with APCD. 

AAS is the most widely used analytical technique for the determination of lead in biological materials [57,58], The majority of AAS methods employ the electrothermal atomic absorption spectrometry (ETAAS) technique, using either Zeeman background correction or deuterium background correction for the determination of lead in biological fluids [55,59-65], Urine is less often employed as an indicator of exposure however, similar problems associated with AAS determination of lead exist for blood as well as urine (1) incomplete atomization (2) volatile lead salts (3) spectral interferences (4) buildup of carbonaceous residue reducing sensitivity and precision. These analytical problems are eliminated by optimal sample preparation, e,g., dilution, addition of matrix modifiers, deproteinization, and background correction and calibration by matrix-matched standards [66],... 

Today, there is strong interest in the development of online sample treatment techniques that allow the handling of untreated biological samples. Thus, in online SPE-LC, deproteination of plasma and serum is required before extraction, especially if the same cartridge is used for repeated analysis. For this purpose, restricted-access materials (RAMs) have been developed, which combine size-exclusion and reversed phase mechanisms, allowing extraction and cleanup of samples in the same step. RAMs have became quite popular for the direct injection of biological fluids, since they prevent the access of matrix components (e.g., proteins) while retaining the analytes in the interior of the sorbent. 

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