Laboratory SOPs

Common buffers

Artificial Saliva
Component wt%
NaCl 0.08
KCl 0.12
MgCl2.6H2O 0.01
K2HPO4 0.03
CaCl2.2H2O 0.01
Na-CMC 0.1
Water 99.6
Dissolve phospahte separately and mix with the rest. Na-CMC can be replaced by guar gum. Good for one week if use sterile water. Adding 0.1-0.25% antimicrobial QAS will extend storage if using non-sterile water. Adding 0.002% NaN3 can also prevent microbial growth. - (Commented by Dr. Fan)
Ref: Oshiro M, Yamaguchi K, Takamizawa T, Inage H, Watanabe T, Irokawa A ,et al. (2007). Effect of CPP-ACP paste on tooth mineralization: anFE-SEM study. J Oral Sci 49: 115-120.
Artificial Saliva- 2 (1 Liter)
Component Mass, gram
CaCl2·2H2O 0.103
KCl 2.24
MgCl2.6H2O 0.019
HEPES buffer (acid) 4.47
KH2PO4 0.544
for 1000 mL and final pH =7.00
Ref: Arı H, Dönmez N, Belli S. Effect of artificial saliva contamination on bond strength to pulp chamber dentin. Eur J Dent. 2008;2(2):86-90.
Hanks buffer solution 1L for tooth storge
Component grams
Sodium Chloride-NaCl 8
Potassium Chloride -KCl 0.12
KH2PO4 0.06
Magnesium Sulfate. 7H2O 0.148
or: Magnesium Sulfate anhyd. 0.098
CaCl2.2H2O 0.18
or CaCl2 0.14
Dissolve phospahte separately and mix with the rest to be one liter. pH =7.0-7.2. Good for four months if use sterile water. Adding 0.1-0.25% antimicrobial QAS will extend storage if using non-sterile water. Adding 0.002% NaN3 can also prevent microbial growth. - (Commented by Dr. Fan)
1 litre of 1x phosphate-buffered saline (1x PBS buffer)
Component grams
Sodium Chloride-NaCl 8.00
Potassium Chloride -KCl 0.20
KH2PO4 0.24
Na2HPO4 1.44
  1. Dissolve in 800 ml of distilled H2O
  2. Adjust the pH to 7.4 with HCl or NaOH
  3. Add distilled H2O to 1 liter.
A 10 liter stock of 10x PBS can be prepared by dissolving 800 g NaCl, 20 g KCl, 144 g Na2HPO4 and 24 g KH2PO4 in 8 L of distilled water, and topping up to 10 L. The pH is ~6.8, but when diluted to 1x PBS it should change to 7.4.
Artifical caries solution
Component grams
0.1 M lactic acid 9.01
Calcium Chloride -CaCl2.2H2O 0.441
KH2PO4 0.408
Guar Gum 2.00
  1. Dissolve in 800 ml of distilled H2O. Guar Gum takes time to be fully dissolved.
  2. The pH should be 4.5. adjust with KOH and HCl if needed.
  3. Add distilled H2O to 1 liter.
Adding 0.002% NaN3 can prevent microbial growth.