. 2013 Jul 29;3(3):421–448. doi: 10.3390/life3030421

Table 1.

Amino acids identified in Hydrogen Cyanide (HCN) polymers. The reaction conditions are described together with the material analysed: soluble fraction (solution or soluble oligomers), insoluble fraction (brown or dark precipitates) or raw reaction. c (M) = initial molar concentration of the reactant in aqueous solution; HCN_(L) = HCN in liquid phase; HCN_(G) = HCN in gas phase; d = days; m = moths; y = years;Non hydrolysis = no additional hydrolysis (acid, basic or neutral) was made over the final product analysed; Acid = HCl 6N/100–110 °C/16–24 h; Basic = NaOH 0.1 N/100 °C/6 h; Neutral = NaOH pH 8–8.5/110 °C/6–24 h; GC-MS = Gas Chromatography-Mass Spectrometry; AAA = Automatic amino acid analyzer; PC = paper chromatography; HPLC = High performance liquid chromatography.

Compound	Starting material, c (M)	T (°C)/t/Catalyst	Final product analysed	Hydrolysis	Method of identification	Reference
Glycine	HCN, 0.2	100/1 d/-	Raw mixture	Acid	GC-MS	[75]
	NH₄CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN, 1.5	70/5 d/NH₄OH	Soluble oligomers	Non hydrolysis	PC	[78]
	HCN, 2.2	70/25 d/NH₄OH	Soluble oligomers	Non hydrolysis	PC	[63]
	NaCN, 1	38/3–30 d/NH₄Cl	Black solid	Acid	GC-MS	[46]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA, GC-MS	[80,81]
	HCN, 0.1	r.t./4–12 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid and neutral	GC-MS	[82]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
	HCN, 0.002–0.1	r.t./UV radiation (Hg lamp)/pH (8–9)	Soluble oligomers	Acid	AAA	[69]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.004–0.1	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
	HCN, 0.1	−20/2 m/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
	HCN, 0.1	−20/25 y/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
	HCN, 0.1	−78/25 y/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
Glycinamide	HCN, 1.5	70/5 d/NH₄OH	Soluble oligomers	Non hydrolysis	PC	[78]
Aminomalonic acid	NaCN, 1	38/3–30 d/NH₄Cl	Black solid	Acid	GC-MS	[46]
Alanine	HCN, 1.5	100/1 d/-	Raw mixture	Acid	GC-MS	[75]
	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN, 1.5	70/5 d/NH₄OH	Soluble oligomers	Non hydrolysis-	PC	[78]
	HCN, 2.2	70/25 d/NH₄OH	Soluble oligomers	Non hydrolysis	PC	[63]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA, GC-MS	[80,81]
	HCN, 0.1	r.t./4–12 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid and neutral	GC-MS	[82]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
	HCN, 0.002–0.1	r.t./UV radiation (Hg lamp)/pH (8–9)	Solution	Acid	AAA	[69]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.004–0.1	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
	HCN, 0.1	−20/2 m/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
	HCN, 0.1	−20/25 y/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
	HCN, 0.1	−78/25 y/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
β-alanine	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN, 0.1	r.t./4–12 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid and neutral	GC-MS	[82]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
Sarcosine	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
Serine	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN_(L)	r.t./.4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN, 0.002–0.1	r.t./UV radiation (Hg lamp)/pH (8–9)	Solution	Acid	AAA	[69]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.004	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
2,3-Aminopropioinic acid	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
Aspartic acid	HCN, 0.2	100/1 d/-	Raw mixture	Acid	GC-MS	[75]
	NH₄CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN, 1.5	70/5 d/NH₄OH	Soluble oligomers	Non hydrolysis	PC	[78]
	HCN, 2.2	70/25 d/NH₄OH	Soluble oligomers	Non hydrolysis	PC	[63]
	NaCN, 1	38/3–30 d/NH₄Cl	Black solid	Acid	GC-MS	[46]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA, GC-MS	[80,81]
	HCN, 0.1	r.t./4–12 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid and neutral	GC-MS	[82]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
	HCN, 0.002–0.1	r.t./UV radiation (Hg lamp)/pH (8–9)	Solution	Acid	AAA	[69]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.004–0.1	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH3/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
	HCN, 0.1	−20/2 m/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
	HCN, 0.1	−20/25 y/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
	HCN, 0.1	−78/25 y/NH₃/pH 9.2	Solution	Acid	HPLC	[67]
Diaminosuccinic acid	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA, GC-MS	[80,81]
	HCN, 0.1	r.t./4–12 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid and neutral	GC-MS	[82]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
2-aminoisobutyric acid	HCN, 0.2	100/1 d/-	Raw mixture	Acid	GC-MS	[75]
	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	GC-MS	[80,81]
	HCN, 0.1	r.t./4–12 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid and neutral	GC-MS	[82]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
2-amino-n-butyric acid	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
4-amino-n-butyric acid	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
Threonine	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.004–0.1	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
Glutamic acid	HCN, 0.2	100/1 d/-	Raw mixture	Acid	GC-MS	[75]
	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA, GC-MS	[80,81]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.004–0.1	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
2-methyl aspartic acid	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 6	Raw mixture	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[70]
	NaCN, 0.1	r.t./γ-radiation (⁶⁰Co source)/pH 11.3	Solution	Acid	AAA, GC-MS	[70]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
Ornithine	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH⁴OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
Histidine	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH⁴OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
Valine	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.1	r.t./γ-radiation (⁶⁰Co source)	Raw mixture	Acid	PC, AAA, GC-MS	[84]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
Isoleucine	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN (L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	NaCN, 1	r.t./3 m/pH 9.2 (HCl)	Soluble oligomers	Acid, basic and neutral	GC-MS	[79]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA, GC-MS	[80,81]
	HCN, 0.1	r.t./18 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid, Basic and neutral	GC-MS	[79]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
Leucine	HCN, 1.5	90/18 h/NH₃	Soluble oligomers	Acid	2D-PC, AAA	[77]
	HCN (L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
Citrulline	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
Lysine	NH4CN, 1	90/4 h/-	Brown precipitate	Acid	AAA	[76]
	HCN, 1	90/4 h/NH₄OH (pH 9.58)	Black solid	Acid	2D-PC	[72]
	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 0.1	r.t./1–6 m/NH₄OH (pH 9.2)	Soluble oligomers	Acid	AAA	[80,81]
	HCN_(G)	r.t./UV radiation (Hg lamp)	Solid	Acid	AAA	[83]
	HCN, 0.1	r.t.−40 °C/γ-radiation (⁶⁰Co source)/NH₃/pH 9	Solution	Acid	AAA, GC-MS	[71]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]
Arginine	HCN_(L)	r.t./4 w/anhydrous NH₃	Dark solid residue	Acid	AAA	[51]
	HCN, 1.5	Refrigerator/4 d/NH₃	Black Solid	Acid	AAA	[51]