Voyager DP-263-S Betriebsanweisung PDF herunterladen (Seite 138)

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101

Chapter 3 Preparing Samples

3-8 PerSeptive Biosystems

CHCA

Use

-cyano-4-hydroxycinnamic acid (CHCA) for:

• Dried drop application—Peptides/proteins <10,000 Da

• Thin layer application—Peptides <~3,000 Da

CHCA for dried

droplet application

Use for peptides/proteins <10,000 Da.

Matrix concentration 10 mg/ml

Final sample concentration 0.1–5 pmol/µl

Solvents Acetonitrile, 0.1% TFA in deionized water

Preparation Follow the procedure in “Preparing matrix” on

page 3-5 and combine one part 0.1% TFA solution

with one part acetonitrile. Dissolve the matrix at a

concentration of 10 mg/ml (for example, add 500 µl

0.1% TFA solution and 500 µl acetonitrile to 10 mg

of solid matrix).

Air dry sample plate after loading sample and matrix,

or use gentle air flow to speed drying.

NOTE: If the dry matrix is a mustard-yellow color instead of bright yellow, it may

contain impurities. To recrystallize (purify), dissolve the

-cyano matrix in warm

ethanol. Filter and add about two volumes of deionized water. Let stand in the

refrigerator overnight. Filter, then wash the precipitate with cold water. This

procedure is not optimized for yield.

NOTE: The organic concentration above assumes you are premixing sample

solution:matrix solution in a 1:10 dilution. If you are mixing sample solution:matrix

solution on the plate in a 1:1 dilution, increase the proportion of acetonitrile to

60 percent to prevent the matrix from precipitating. Adjust the other components

accordingly.

NOTE: A higher concentration of TFA (up to 3%) may improve sample solubility.

Crystals Rounded (see Figure 3-1 on page 3-34)

Stability Prepare weekly.

1. Shevchenko, A., M. Wilm, O. Vorm, M. Mann,

Anal. Chem.,

1996, 68, 850–858.

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