TE buffer (Tris-EDTA buffer) Recipe

The purpose of TE buffer is to solubilize DNA or RNA, while protecting it from degradation.

10 mM Tris, bring to pH 8.0 with HCl, 1 mM EDTA

A stock can be prepared and stored at RT

Component For 500ml
1M Tris pH 8* 5ml
0.5M EDTA pH 8 1ml
dH2O 496ml

Autoclave to sterilize. It is then best to remove a working aliquot and not repeatedly access the stock.
*the pH is usually adjusted to RNA 8.0 for DNA and 7.5 for

How to make acetate-acetic acid buffer solutions

Sodium acetate-acetic acid buffer solutions, pH 3.7-5.6

Sodium acetate trihydrate, CH3COONa.3H2O, M.Wt. 136.09;
0.2M solution contains 27.22g/l.
Acetic acid, glacial is ~17.47M.

x ml 0.2M NaOAc and y ml 0.2M HOAc mixed.

pH, 18°C X mL

0.2M NaOAc

Y mL

0.2M HOAc
3.7 10.0 90.0
3.8 12.0 88.0
4.0 18.0 82.0
4.2 26.5 73.5
4.4 37.0 63.0
4.6 49.0 51.0
4.8 59.0 41.0
5.0 70.0 30.0
5.2 79.0 21.0
5.4 86.0 14.0
5.6 91.0 9.0

How to Dilute a Stock Solution

How to Dilute a Stock Solution


A. Why dilute? 

Here are two situations that arise repeatedly in molecular biology labs:
1. You have a stock solution of some compound,  let’s say an antibiotic, and you want to add the
compound to growth medium, at a much smaller concentration than the stock solution.
2. You have a tube of very concentrated bacteria, perhaps a billion cells per milliliter. You want to put
a few hundred of them on a petri plate, so that the colonies that arise will be easily distinguishable.
In both cases, the way out of the problem is to dilute the original solution. If you work in a lab, you need to
know how to do this.

B. Methods of calculating dilutions 

1. DILUTION FACTOR METHOD (fast, but requires inspiration): First, figure out the factor by which the
original solution must be diluted. Second, divide the final volume of the desired solution by that
factor, yielding the volume required of the original solution.
EXAMPLE: Suppose you need to make a 3 ml solution of growth medium supplemented with 50 µM of
the antibiotic ampicillin from a stock solution of 5 mM ampicillin. The dilution factor is :
  (5 mM) / (50 µM) = (5000 µM) / 50 µM) = 100
 so you need to dilute:
   (3 ml) / 100 = (3000 µl) / 100 = 30 µl
 of the stock solution to a final volume of 3 ml.

2M H2SO4 for 100ml

2M H₂SO₄ for 100ml

• mix 50ml Milli Q water + 50ml 4M H₂SO₄ solution

4M H2SO4 for 1 liter

4M H₂SO₄ for 1 liter

• Carefully pour 392ml H₂SO₄ {Sulphuric acid 96% H₂SO₄ Carlo Erba reagents Code no. 410301 (Reanal 17769) FW 98.078} into 608ml Milli Q water (always pour acide into water)

TMB-buffer for 1 liter

TMB-buffer for 1 liter[0.1M Na-acetate, pH 5.5]

• Disolve in 950ml Milli Q water
• 13.6g Na-acetate {Nátrium acetát, kristályvizes CH₃COONa*3H₂O M:136.08 Reanal 14021}
• Adjust pH to 5.5 with app. 700ul cc. Acetic acid {Ecetsav 96% Reanal 0914-1-08-65 M:60.05}
• Adjust volume to 1 liter with Milli Q water 

TMB solution for 1ml - ELISA

TMB solution for 1ml [10mg/ml TNB in DMSO]

• Disolve in 1ml DMSO {Dimethyl sulfoxide, minimum 99.5% GC Sigma D5879-100ml }
• 10mg TNP {3,3',5,5'-tetramethyl-benzidine Sigma T-2885 FW240.3}
• Store at +4C

ELISA blocking-buffer for 10ml

ELISA blocking-buffer for 10ml [0.05% Tween 20, 5%BSA, 0.05% azide, PBS]

• Mix on magnetic stirrer:
• 10ml PBS-Tween
• 100mg BSA {Sigma, No.:A3059-100G, Albumin, bovine serum, Fraction V}
• 50ul Sodium azide (from 10% NaN₃ stock solution)
• Store at +4C

Carbonate buffer pH 9.5 for 1 liter (for ELISA coat)

Carbonate buffer pH 9.5 for 1 liter (for ELISA coat) Disolve in 1 liter Milli Q water: 1.6g Na2CO3 2.9g NaHCO3 Adjust to pH 9.5 Store at R/T

5x Veronal buffer for 500ml (5xVBS) Recipe

5x Veronal buffer for 500ml (5xVBS) [727mM NaCl, 9.12mM Na-diethyl-barbiturate (C8H11O3N2Na), 15.63mM 5,5’-diethyl barbiture acid (C8H12N2O3), pH7.3] Make solution 'A': 0.94g Na-diethyl-barbiturate (C8H11O3N2Na){5,5-Diathylbarbitursaure. Na-salz Serva 18797; MW:206.2} 21.25 g NaCl {Reanal, No.:2464-1-22-38, Nátrium-klorid, Ph. Eur.5; MW:58.44} ~300ml Milli Q water Make solution 'B': 1.44g 5,5’- diethyl barbiture acid {5,5-dietil-barbitursav Reanal 04049; MW:184.2} ~100ml Milli Q water Boil it otherwise it won’t dissolve, then cool it down Mix solution ‘A’ and ‘B’ set pH to 7.3 with app. 50-70μl 10N NaOH Fill up until 500ml with Milli Q water, then store it at +4C

1x Veronal buffer recipe

1x Veronal buffer (VBS)[145mM NaCl, 1,8mM Na-diethyl-barbiturate (C8H11O3N2Na), 3mM 5,5’-diethyl barbiture acid (C8H12N2O3), pH7.3] Dilute 5x Veronal buffer with Milli Q water

0.2M EGTA stock solution for 10ml

0.2M EGTA stock solution for 10ml Mix on magnetic stirrer: 8ml Milli Q water 0.7608g EGTA{ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) Sigma E-4378 LOT 111K5411 FW 380,4} Adjust to pH8 with 10N NaOH otherwise it won't disolve (be careful EGTA is an acid) Adjust volume to 10ml with Milli Q water Store at 4C

EDTA-VBS solution for 10ml

EDTA-VBS solution for 10ml (dilute serum 5x with it)[25mM EDTA, 5%BSA, 0.05% Tween 20, VBS ] Mix on magnetic stirrer: 2ml 5x VBS 500ul 0.5M EDTA 0.5g BSA {Sigma, No.:A3059-100G, Albumin, bovine serum, Fraction V} 50ul 10% Tween 20 {Sigma No.:P-1379, Polyoxylethylene-sorbitan monolaurate (Tween 20)} Adjust volume to 10ml with Milli Q water Filtrate though an 0.45um filter Aliquot 1ml/eppendorf Store at -20C

Mg-EGTA-VBS solution for 10ml

Mg-EGTA-VBS solution for 10ml (dilute serum 5x with it)[2.5mM Mg2+, 6.2mM EGTA, 5%BSA, 0.05% Tween 20, VBS] Mix on magnetic stirrer: 2ml 5x VBS 310ul 0.2M EGTA 25ul 1M MgCl2 stock solution 0.5g BSA {Sigma, No.:A3059-100G, Albumin, bovine serum, Fraction V} 50ul 10% Tween 20 {Sigma No.:P-1379, Polyoxylethylene-sorbitan monolaurate (Tween 20)} Adjust volume to 10ml with Milli Q water Filtrate though an 0.45um filter Aliquot 1ml/eppendorf Store at -20C

Ca-Mg-VBS (veronal buffered saline) for 25ml

Ca-Mg-VBS (veronal buffered saline) for 25ml (for serum dilution)[2.5mM Ca2+, 0.7mM Mg2+, 0.05% Tween 20, 5%BSA, VBS] Mix on magnetic stirrer: 5ml 5x VBS 250ul Ca2+ Mg2+ stock solution [0.25M Ca2+, 0.07M Mg2+] 1.25g BSA {Sigma, No.:A3059-100G, Albumin, bovine serum, Fraction V} 12.5ul Tween 20 {Sigma No.:P-1379, Polyoxylethylene-sorbitan monolaurate (Tween 20)} Adjust volume to 25ml with Milli Q water Filtrate though an 0.45um filter Aliquot 1ml/eppendorf Store at -20C

Ca2+ Mg2+ stock solution for 5ml [0.25M Ca2+, 0.07M Mg2+]

Ca2+ Mg2+ stock solution for 5ml [0.25M Ca2+, 0.07M Mg2+] Dissolve in 5 ml Milli Q water: 0.1838g CaCl2*2H2O {Reanal 11024 MSZ 24161-65 Kalcium-klorid, szárított MW: 147.02 CaCl2*2H2O} 0.0712g MgCl2*6H2O {Reanal No.: 20281-1-01-38 Magnézium-klorid 6-hidrát MW: 203.30 MgCl2*6H2O}

PBS-Tween BSA for 300ml [0.05% Tween 20, 5%BSA, 0.05% azide, PBS]

PBS-Tween BSA for 300ml [0.05% Tween 20, 5%BSA, 0.05% azide, PBS] Mix on magnetic stirrer: 300ml PBS-Tween 15g BSA {Sigma, No.:A3059-100G, Albumin, bovine serum, Fraction V} 1.5ml Sodium azide (from 10% NaN3 stock solution) Filtrate through an 0.45um filter Aliquot 50ml/falcon Store at 4°C

PBS-Tween for 1 liter [0.05% Tween 20, PBS]

PBS-Tween for 1 liter [0.05% Tween 20, PBS] Mix on magnetic stirrer: 0.5ml Tween 20 {Sigma No.:P-1379, Polyoxylethylene-sorbitan monolaurate (Tween 20)} 1 liter PBS

1x PBS Recipe for 1 liter[137mM NaCl, 2.7mM KCl, 8mM Na2HPO4, 1.46mM KH2PO4]

Dissolve in 800 ml distilled water: 8 g NaCl {Reanal, No.:2464-1-22-38, Nátrium-klorid, Ph. Eur.5; MW:58.44} 0.2 g KCl {Reanal, No.:18050-1-01-38, Kálium-klorid, a.r.; MW: 74.56} 1.424 g Na2HPO4*2H2O {Reanal, No.:08973-1-01-38, di-Nátrium-hidrogén-foszfát 2-hidrát, a.r.; MW:177,99} 0.2 g KH2PO4 {Reanal, No.:17890-01-38, Kálium-dihidrogén-foszfát, a.r.; MW:136.09} Adjust volume to 1 liter with H2O Filtrate trough an 0.22um filter or sterilize by autoclave Store at room temperature

10x PBS Recipe for 1 liter

10x PBS Recipe for 1 liter Dissolve in 800 ml distilled water: 80 g NaCl {Reanal, No.:2464-1-22-38, Nátrium-klorid, Ph. Eur.5; MW:58.44} 2 g KCl {Reanal, No.:18050-1-01-38, Kálium-klorid, a.r.; MW: 74.56} 14.24 g Na2HPO4*2H2O {Reanal, No.:08973-1-01-38, di-Nátrium-hidrogén-foszfát 2-hidrát, a.r.; MW:177,99} 2 g KH2PO4 {Reanal, No.:17890-01-38, Kálium-dihidrogén-foszfát, a.r.; MW:136.09} Adjust volume to 1 liter with H2O Filtrate through an 0.22um filter and divide in 500ml aliquotes Store at room temperature