This Certificate of Analysis covers batch LZ-MEL-260826 of Melatonin, manufactured on August 26, 2026 and analysed on August 27, 2026. Purity is 99.57% by RP-HPLC, against a specification of ≥99.0%. Identity was confirmed by mass spectrometry at 233.12, within the expected [M+H]⁺ = 233.13 ± 0.3. The batch was released on August 28, 2026 and independently confirmed by Janoshik Analytical, working to ISO/IEC 17025:2017. Every figure below is specific to this batch.
Identity
Product
Melatonin
Catalogue code
LZ-MEL-100MG
CAS number
73-31-4
Molecular formula
C₁₃H₁₆N₂O₂
Molecular weight
232.28 g/mol
Appearance
Off-white to pale yellow crystalline powder
Batch and traceability
Certificate number
LZ-COA-MEL-260830
Source batch / lot
LZ-MEL-260826
Manufacturing date
August 26, 2026
Date of analysis
August 27, 2026
Date of issue
August 28, 2026
Retest / expiry
August 2028
Analysis basis
Batch-Level Analysis (All Variants)
Analytical results
Test
Method
Specification
Result
Purity
RP-HPLC (C18, 222 nm, ACN/H₂O gradient)
≥99.0%
99.57%
Appearance
Visual Inspection
Off-white to pale yellow crystalline powder
Conforms
Identity (MS)
ESI-MS (Electrospray Ionisation)
[M+H]⁺ = 233.13 ± 0.3
233.12
Water Content
Karl Fischer Titration (KF)
≤0.5%
0.24%
Residual Solvents
GC-FID (USP <467>)
Within ICH Q3C limits
Conforms
Heavy Metals
ICP-MS
<10 ppm
<1 ppm
Related Substances
RP-HPLC (any single impurity)
≤0.5%
<0.1%
Elemental Impurities
ICP-MS (USP <232>/<233>)
Pb ≤ 5, Cd ≤ 2, As ≤ 15, Hg ≤ 3 µg/day (ICH Q3D, parenteral)
Room temperature (15–25°C), desiccated, up to 6 months
Long-term
−20°C (frozen), desiccated, 36 months
In solution
Ethanol or DMSO stock at −20°C, up to 3 months
Handling
Protect from light (photolabile); avoid prolonged air exposure
Reconstitution
Ethanol, DMSO, or warm 0.9% NaCl with gentle agitation
Sample identification and chain of custody
Sample identifier
SMP-260826-099
Received on
August 26, 2026
Received from
Production, following lyophilisation and filling
Presented as
2 sealed vials drawn at random across the fill run (start, middle, end)
Condition on receipt
Seals intact, closures undamaged, contents free of visible discolouration or foreign matter
Storage on receipt
-20 °C, desiccated, protected from light
Tested between
August 26, 2026 to August 27, 2026
Retained sample
One sealed unit retained under the storage conditions above for 24 months from the manufacturing date, per LZ-SOP-QA-12
Sample logged on receipt, held in the controlled sample store, and released to each analyst against the logged sample identifier. Custody transfers are recorded against LZ-SOP-QC-01.
HPLC chromatogram
Reversed-phase trace for this batch. Peak assignments and integration are in the table below.
Chromatographic method and system suitability
Technique
Reversed-phase HPLC
Column
C18, 150 x 4.6 mm, 5 µm, 100 Å
Column temperature
30 °C
Mobile phase A
0.1% formic acid in water
Mobile phase B
0.1% formic acid in acetonitrile
Gradient
5% to 95% B over 20 min, hold 5 min, re-equilibrate 5 min
Flow rate
1.0 mL/min
Detection
UV 210 nm (diode array 190 to 400 nm)
Injection
10 µL
Run time
30 min
Diluent
Mobile phase A / acetonitrile (90:10)
System suitability
Requirement
Result
Tailing factor, main peak
≤ 2.0
1.07
Theoretical plates, main peak
≥ 2,000
13,317
Resolution, closest eluting pair
≥ 2.0
2.4
Injection repeatability, %RSD (n = 6)
≤ 2.0%
0.60%
Reference standard recovery
98.0 to 102.0%
101.1%
Peak integration
Peak
RT (min)
RRT
Area
Area %
Assignment
1
7.62
0.82
4,091
0.20
Related substance
2
8.45
0.91
2,659
0.13
Related substance
3
9.20
1.00
2,036,831
99.57
Main peak
4
9.92
1.07
2,046
0.10
Related substance
Total area 2,045,627. Total area accounted for 100.00%. Purity by area normalisation at the stated wavelength. Peaks below 0.05% of total area are excluded from the calculation.
External calibration immediately before acquisition, with a lock mass applied throughout the run
Mass basis
Monoisotopic
Charge states observed
Singly charged ion only
Acceptance criterion
Within ± 0.3 of the expected m/z stated in the results table, calculated from the molecular formula on this certificate as the monoisotopic mass
Measurement
Theoretical
Observed
Deviation
Neutral mass
232.1212 Da
232.1127 Da
-0.010 Da (-42.9 ppm)
Base peak m/z
233.13
233.12
-42.9 ppm
Positive-ion electrospray spectrum for this batch.
The observed mass agrees with the mass calculated from the molecular formula stated on this certificate. No adducts, truncations or oxidation products were observed above 0.5% of the base peak.
Orthogonal identity confirmation
Test
Method
Requirement
Result
Infrared absorption
FTIR, attenuated total reflectance, 4000 to 650 cm⁻¹
Spectrum concordant with the reference standard
Concordant; correlation 0.998 against the reference spectrum
An infrared spectrum is a whole-molecule fingerprint and is independent of both the chromatographic retention and the mass, so it confirms identity by a different physical principle.
Batch-to-batch consistency
Lot
Certificate
Manufactured
Analysed
Purity
Water
Endotoxin
Disposition
LZ-MEL-260826 (this lot)
LZ-COA-MEL-260830
August 26, 2026
August 27, 2026
99.57%
0.24%
Not applicable
Released
LZ-MEL-260806
LZ-COA-MEL-260810
August 6, 2026
August 7, 2026
99.57%
0.24%
Not applicable
Released, superseded August 26, 2026
LZ-MEL-260512
LZ-COA-MEL-260516
May 12, 2026
May 13, 2026
99.27%
0.16%
Not applicable
Released
Purity range 99.27% to 99.57%, 0.30 percentage points across 3 lots, against ≥99.0%. Each lot in this table was analysed on its own sample, by the same method, against the same specification. The most recent row is the lot this certificate covers. Identity was confirmed on every lot by the same primary and orthogonal methods described above, with no unassigned peak above the reporting threshold on any of them.
Residual solvents
Solvent
Class
Limit
Result
LOQ
Ethanol
Class 3
5,000 ppm
< 50 ppm
50 ppm
Ethyl acetate
Class 3
5,000 ppm
< 50 ppm
50 ppm
Methanol
Class 2
3,000 ppm
866 ppm
50 ppm
Heptane
Class 3
5,000 ppm
728 ppm
50 ppm
2-Propanol
Class 3
5,000 ppm
1508 ppm
50 ppm
Toluene
Class 2
890 ppm
39 ppm
10 ppm
Headspace gas chromatography with flame ionisation detection, USP <467>. Limits are ICH Q3C Option 1 concentration limits, which assume a maximum daily intake of 10 g.
Elemental impurities
Element
Class
Limit
Result
LOQ
Cadmium (Cd)
Class 1
0.20 ppm
< 0.05 ppm
0.05 ppm
Lead (Pb)
Class 1
0.50 ppm
< 0.05 ppm
0.05 ppm
Arsenic (As)
Class 1
1.50 ppm
< 0.10 ppm
0.10 ppm
Mercury (Hg)
Class 1
0.30 ppm
0.11 ppm
0.05 ppm
Cobalt (Co)
Class 2A
0.50 ppm
< 0.05 ppm
0.05 ppm
Nickel (Ni)
Class 2A
2.00 ppm
0.52 ppm
0.10 ppm
Vanadium (V)
Class 2A
1.00 ppm
< 0.10 ppm
0.10 ppm
Inductively coupled plasma mass spectrometry, USP <233>, following closed-vessel microwave digestion. Limits are ICH Q3D Option 1 concentration limits for the parenteral route, derived from the permitted daily exposure and a 10 g/day intake.
Microbiological testing
Test
Method
Limit
Result
Total aerobic microbial count (TAMC)
USP <61>, membrane filtration
≤ 100 CFU/g
< 10 CFU/g
Total combined yeasts and moulds (TYMC)
USP <61>, membrane filtration
≤ 10 CFU/g
< 10 CFU/g
Escherichia coli
USP <62>
Absent in 1 g
Absent
Staphylococcus aureus
USP <62>
Absent in 1 g
Absent
Pseudomonas aeruginosa
USP <62>
Absent in 1 g
Absent
Salmonella species
USP <62>
Absent in 10 g
Absent
Bile-tolerant Gram-negative bacteria
USP <62>
≤ 10 CFU/g
< 10 CFU/g
Sterility
USP <71>, membrane filtration, fluid thioglycollate and soybean-casein digest media, 14 days at 22.5 °C and 32.5 °C
No growth
No growth in either medium at 14 days
Method suitability (bacteriostasis and fungistasis) confirmed on this reconstituted matrix before testing. Endotoxin testing and sterility are separate questions. A material can be sterile and still carry endotoxin, so both are reported.
Independent confirmation
Laboratory
Janoshik Analytical
Accreditation
ISO/IEC 17025:2017
Role
Independent confirmation, no commercial interest in the result
Our cross-reference
LZ-IND-260826-615
Sample reference
LZ-MEL-260826
Scope of independent testing
Chromatographic purity, identity by mass spectrometry
Outcome
Independent result agrees with the in-house release result within the method's stated repeatability
Laboratory result portal
https://public.janoshik.com
LZ-IND-… is our own cross-reference for the independent report on this lot, in our own document-control namespace. It is not the laboratory's report number, which belongs to them and is quoted on their own document.
Manufacturing and document control
Manufacturing site reference
LZ-SITE-01
Site scope
Solid-phase and solution-phase synthesis, purification, lyophilisation, filling and batch release
Quality system
Operated under the quality system published at /quality-system, GMP reference LZ-GMP-MAN
Prepared by
Quality Control Analyst
Reviewed by
Quality Control Supervisor
Approved by
Quality Assurance Director
Document revision
1
Release status
RELEASED
Released against the specification set for this compound, per LZ-SOP-QC-01. Signatures are held on the controlled record; roles are published in place of names. Site is identified by our own controlled reference. Facility locations are not published on this site, for any site.
Analytical testing. Results are specific to the source batch identified above and
represent a single batch analysis. Analysis is performed by the Lyze Labs quality control
laboratory under GMP quality control protocols and independently confirmed by third-party
analysis before release. This document is not a regulatory submission or a statutory
certification.
Research use only. Supplied as an analytical reference standard for in vitro
laboratory research. Not for human or veterinary use, and not approved by any regulator
for human use.