EDTA buffers

Fig. 4.3.1 Effect of pH on the total light emission of phialidin (A), and the temperature stability profiles of phialidin (minute open circles) and aequorin (solid line) (B). In A, each buffer contained 0.1 M CaCl2 plus 0.1 M Tris, glycine or sodium acetate, the pH being adjusted with NaOH or HC1. In B, the photoprotein samples in 10 mM Tris-EDTA buffer solution, pH 8.0, were maintained at a test temperature for 10 min, and immediately cooled in an ice water bath. Then total luminescence activity was measured by injecting 1ml of 0.1 M CaCl2/Tris-HCl, pH 7.0, to 10 pd of the test solution. From Levine and Ward (1982), with permission from Elsevier.

Stellwagen, NC, Apparent Pore Size of Polyacrylamide Gels Comparison of Gels Cast and Run in Tris-acetate-EDTA and Tris-borate-EDTA Buffers, Electrophoresis 19, 1542, 1998. Stellwagen, NC Gelfi, C Righetti, PG, The Free Solution Mobility of DNA, Biopolymers 42, 687, 1997. 

Three pH values (acidic, neutral, and basic AR solution), and three heating conditions (under boiling, boiling, and pressure heating) are recommended for the basic test battery. However, alternative procedures may be applied according to laboratory facilities and routine protocols as described above. Currently, citrate buffer pH 6.0, Tris-EDTA buffer pH 8-9, and certain AR solutions at lower pH, such as boric acid pH 2-3, or acidic acid buffer pH 2, as well as 0.05% citraconic anhydride pH 7.4, may be used to evaluate the optimal AR protocol. 

Purify the biotinylated protein by gel filtration using a desalting resin or by dialysis. The PBS/EDTA buffer described in step 1 is suitable for either operation. 

Fig. 17.11. Bottom CGE separation of components of poly U (sigma) in 25% pluronic F127. Top Note the resolution of two contaminants between each of the oligonucleotides from about 15 to 27 nucleotides long in this expanded section of the bottom electropherogram. Electrophoresis was performed in 25% pluronic F127 in tris-borate-EDTA buffer (90 mM tris, 90 mM boric acid, 2 mM Na EDTA, pH 8.3.) (25°C, 500 V cm-1, effective column length 30 cm). Reprinted with permission from Ref. [82],...

Target Retrieval Solutions from DAKO with pH 6.0 or pH 9.0 are well-suited for use on formalin-fixed, paraffin-embedded tissue sections mounted on glass slides. Compared with 0.01 M Citrate buffer, pH 6, the use of 0.001 M EDTA buffer, pH 9, significantly improves staining results for many antigens, preserves the morphology better and is especially useful in combination with the Dako EnVision visualization systems. 

EDTA buffer wash - dissolve 40 g tetrasodium EDTA, and 6.75 g ammonium chloride in approximately 800 ml water, then, in a fume cupboard, carefully add 57 ml ammonia solution (approximately 35% m/m NH3). Stir and make up to 1 I with water. 

Fig. 6. Apoptotic DNA ladder pattern of eosinophils treated with dexamethasone (Dexa, 2 (xM) for 18 h (Zl). DNA was extracted from cells with ethanol (P4) and electrophoresed on 1% agarose gel in 1 X TAE (Tris acetate-EDTA) buffer (pH 8.0). After electrophoresis, the gel was soaked in 1 x TAE buffer containing 0.5 /tg/ml ethidium bromide, and DNA was visualized by an ultraviolet illuminator. Reproduced with permission from Zhang, J. R, Wong, C. K., Lam, C. W. K., Ho, C. Y., and Hjelm, N. M., Biochemical assessment of apoptosis. Chinese J. Lab. Med. Clin. Sci. 1, 27-28 (2000).

Tris-Acetate-EDTA buffer (50x) [TAE Buffer] pH 8.3 (Nacalai Tesque) Store at room temperature. 

Ethylenediaminetetraacetic acid disodium salt dehydrate (EDTA) buffer solution... 

Homogenate buffer sucrose 171 mg/2 ml Tris-HCl/EDTA buffer (MW 342.30 —> 250 mM). Prepare fresh ... 

In this assay, milk samples could be analyzed without dilution, but tissue and egg white samples should be homogenized in 5% trichloroacetic acid, centrifuged, and brought to pH 7 prior to analysis. Egg yolks required a separate treatment involving mixing with a pH 7.4 phosphate-EDTA buffer, incubation for 3 h at 25 C with cephalexin antiserum and enzyme-label cephalexin, and centrifugation. The assay could detect cephalexin down to 30 ppb in milk, 60 ppb in egg yolk, and 400 ppb in hen tissue. 

MclIvaine/EDTA buffer extn, heat deprtn, SPE cleanup... 

Sample extraction/deproteinization is usually accomplished with mild acidic solvents to free the noncovalently bound tetracyclines from macromolecules. Mcllvaine buffer, pH 4.0 (286, 287), Mcllvaine/EDTA buffer, pH 4.0 (283, 287-293), succinate buffer, pH 4,0 (278-281,294-296), acidic acetonitrile (297-299), and acidic methanol (14, 199, 300) have all been used successfully. Moreover, trichloroacetic acid, pH 2.0 (301, 302), metaphosphoric acid (303), acetate buffer (126, 280), citrate buffer, pH 4.0 (304), citrate buffer/ethyl acetate, pH 4-5 (305), and hydrochloric acid/glycine buffer (306, 307) have all been employed with varying success to precipitate proteins from the sample homogenates. 

Mcllvaine/EDTA buffer homogenization/precipitation-SPE assays... 

B. Mcllvaine/EDTA Buffer Homogenization/Precipitation-SPE Assays... 

The milk/tissue sample was homogenized/extracted with Mcllvaine-EDTA buffer (pH 4.0). The pellet was resuspended and extracted again. The combined extracts were further filtrated on a paper disk to remove any solid particles that might result in the plugging of an SPE cartridge. The extract was loaded on a preconditioned SPE cartridge (with MeOH and water), and TCs were eluted with 10 mM oxalic acid solution in MeOH. 

The homogenization with both Mcllvaine-EDTA buffer (pH 4.0) and n-hexane dichloro-methane was presented for the determination of OTC in eggs and OTC, TC, and CTC in muscle. The proteins were further precipitated with the addition of TCA, and TCs were preconcentrated on a C18 SPE cartridge (34,35). 

The assay based on a homogenization with Mcllvaine/EDTA buffer followed by SPE on a C18 cartridge (as described earlier) was evaluated for the determination of OTC, TC, and CTC residues in pork/beef kidney and muscle samples in 13 laboratories, and the results were com-... 

Most of the LC-MS assays for the determination of TCs in food samples were based on a sample homogenization/precipitation with Mcllvaine-EDTA buffer followed by SPE on a C18 cartridge. Only one paper presented a combination of MCAC assay with LC-MS analysis (28) thus, it was reviewed in the previous section. 

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