Reagent solutions labeling

The methods for using this reagent in labeling glycoproteins on cell surfaces or in solution are similar to those described for fluorescein-5-thiosemicarbazide, above. 

The first experimental demonstration of such a device has been published by Jacobson et al. [53]. Amino acids were injected by a gated injection scheme, separated in a 7 mm channel and subsequently labeled by controlled mixing with an o-phthaldialdehyde reagent solution at a T-intersection. The separation efficiency achieved, however, was relatively poor and the inadequate kinetics of the labeling reaction caused significant band broadening. 

Are reagents and solutions labeled correctly with expiration dates ... 

Providing all the reagents, solutions and apparatus are at hand a set of 2-4 M13 recombinant DNA samples can be sequenced in an 8 hour working day. When using fresh a-32P dATP label overnight autoradiography is often sufficient and if all is well sequences totalling 500-1000 nucleotides may be determined daily. 

C-toluene standard—In a fume hood, mix sufficient 14C-toluene and unlabeled toluene to yield a known quantity of 14C-toluene (e.g., 1 to 2 nCi of 14C-toluene) per 0.1 ml of toluene solution. Label the sample with the 14C-toluene/ml with known disintegrations per minute (dpm). Y)u will need 250 ml of this solution. Save 50 ml of this reagent for the quenched 14C unknown. Dispense the other 200 ml to the students. 

Antipyrine-H2S04 reagent—Carefully add 1.25 liters of concentrated H2S04 to 1.25 liters of distilled water and allow to cool. Dissolve 12.5 g of antipyrine in the H2S04 solution. Label with warning strong acid. 

All reagent solutions must be clearly labelled with the name and concentration of the reagent and the name of the person responsible for it. 

For reporter groups sensitive to the reagents used in cleavage-deprotection of the PNA, labeling of the PNA in solution postsynthetically is performed (Fig. 10). The PNA should be purified (typically by reverse-phase HPLC) before attempting solution labeling. This is customarily accomplished as follows ... 

This method is based on the chemical reaction of the constituent of interest with a radio-labeled reagent. The labeled component is then released either as a gas or in some readily extractable form. From a measurement of the amount of radioactivity released and the stoichiometry of the reaction, the quantity of the constituent of interest is determined. Consider the determination of SO2 in air by this method. If air is passed through a basic solution of KPO3, the following reaction takes place ... 

Phenyldimethylsilyl chloride has been introduced as a reagent for labelling alditols and mono- and di-sacdtarides [135]. The derivatization was carried out in N,N-dimethyl-formamide. Imidazole solution (200 fi, 0.33 g ml ) was added to a solution of the carbohydrate (<10mg). The mixture was then heated at 100 C for 1 h. After... 

Labeled primers Oligonucleotide primers are easily labeled on the 5 -phosphate group with biotin, digoxygenin, dinitrophenol, other haptens, fluorescein, other fluorophores, and many other reagents. These labels can be used for either capture or detection. To increase specificity, the primer label is generally used for capture, rather than for detection. Thus, hybridization to a labeled oligonucleotide probe can be performed in solution where kinetics are more rapid, and followed by capture on the solid phase. 

In each solution, curved arrows show formation of the new carbon-carbon bond and the alkoxide ion. The new carbon-carbon bond formed by each set of reagents is labeled in the final product. 

A concentrated C.P. reagent usually comes to the laboratory in a bottle having a label which states its molecular weight w, its density (or its specific gravity) d, and its percentage assay p. When such a reagent is used to prepare an aqueous solution of desired molarity M, a convenient formula to employ is... 

Isotope labeling by derivative formation with deuterated reagents is useful for the preparation of analogs such as dg-acetonides, da-acetates, da-methyl ethers, dg-methyl esters, etc. The required reagents are either commercially available or can be easily prepared. (The preparation of da-methyl iodide is described in section IX-F. Various procedures are reported in the literature for the preparation of dg-acetone, da-diazometh-ane57.i63.i73 and da-acetyl chloride. ) These reactions can be carried out under the usual conditions and they need no further discussion. A convenient procedure has been reported for the da-methylation of sterically hindered or hydrogen bonded phenolic hydroxyl functions by using da-methyl iodide and sodium hydroxide in dimethyl sulfoxide solution. This procedure should be equally applicable to the preparation of estradiol da-methyl ether derivatives. 

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