AssayIndex

SIG-2602-6794

PEG-MGF · 2 mg declared · Sigma-Aldrich (Shanghai) Trading Co., Ltd. · manufactured 09 Feb 2026

CHARACTERISED
Lot code
SIG-2602-6794
Supplier
SIG — Sigma-Aldrich (Shanghai) Trading Co., Ltd.
Compound
PEG-MGF
Compound class
Growth-hormone axis peptides
Declared label claim
2mg
Manufacture date
09 Feb 2026
Index quarter
2026-Q2
Independent assays
13
Laboratories involved
Janoshik, PeptideMeter, Kestrel, VendorInvestigate, Nordanalyt
Provenance mix
Buyer-sourced ×12 · Laboratory-retained ×1
Section 1

Reproducibility across independent tests

Every report below is an observation of the same physical material. What they disagree about is measurement; what they agree about is the lot. The size of the disagreement is compared against what the contributing laboratories' own repeatability figures predict.

Independent assays 13
Median purity 97.75% n=13
Spread (max − min) 1.30pp n=13
Standard deviation 0.320pp n=13
95.395.996.697.297.898.599.1This lot (SIG-2602-6794)This lot (SIG-2602-6794): Q1 97.57, median 97.75, Q3 97.78, n=13outlier 98.58n=13All PEG-MGFAll PEG-MGF: Q1 97.42, median 97.75, Q3 98.18, n=42outlier 95.57outlier 95.93outlier 95.96outlier 96.04outlier 96.05outlier 96.05n=42 Purity (% area)
Figure 1. This lot's independent purity results against the whole PEG-MGF record set in the index. The vertical line is the index acceptance specification for the growth-hormone axis peptides class, 92.0 % area. A narrow box on the top row against a wide box on the bottom row is the ideal reading: it means the disagreement between lots is much larger than the disagreement within this one.
Section 2

Member reports 13

Every report the index holds on this lot. Each is a page carrying its own chromatogram, mass spectrum, mass balance, provenance and caveats.

ReportLotLabQuarterPurity %Water %Recovery %ProvenanceFlagsResult
AX-2026-043568SIG-2602-6794Janoshik2026-Q297.755.39Buyer-sourced0PASS
AX-2026-043569SIG-2602-6794PeptideMeter2026-Q297.525.36Laboratory-retained0PASS
AX-2026-043570SIG-2602-6794PeptideMeter2026-Q297.765.45104.2Buyer-sourced0PASS
AX-2026-043571SIG-2602-6794Janoshik2026-Q297.755.56Buyer-sourced0PASS
AX-2026-043572SIG-2602-6794PeptideMeter2026-Q297.575.15Buyer-sourced0PASS
AX-2026-043573SIG-2602-6794Janoshik2026-Q298.584.79104.2Buyer-sourced0PASS
AX-2026-043574SIG-2602-6794Kestrel2026-Q298.045.9888.6Buyer-sourced1MARGINAL
AX-2026-043575SIG-2602-6794VendorInvestigate2026-Q297.415.63Buyer-sourced0PASS
AX-2026-043576SIG-2602-6794Nordanalyt2026-Q297.615.56Buyer-sourced0PASS
AX-2026-043577SIG-2602-6794Kestrel2026-Q297.666.08Buyer-sourced0PASS
AX-2026-043578SIG-2602-6794Janoshik2026-Q297.785.76Buyer-sourced0PASS
AX-2026-043579SIG-2602-6794Janoshik2026-Q297.285.80Buyer-sourced0PASS
AX-2026-043580SIG-2602-6794Janoshik2026-Q297.835.5199.3Buyer-sourced0PASS
Section 3

By laboratory

Where more than one laboratory assayed this lot, the difference between them is a paired observation of their relative bias — the same material, the same time window, different instruments. Those pairs are what the index's bias estimates are built from.

LaboratoryReportsPurity results (% area)MedianGradientPublished bias (pp)Bias-adjusted
Janoshik697.75, 97.75, 98.58, 97.78, 97.28, 97.8397.7730min+0.0097.77
PeptideMeter397.52, 97.76, 97.5797.5728min-0.0597.62
Kestrel298.04, 97.6697.8515min+0.2497.61
VendorInvestigate197.4197.4132min-0.1197.52
Nordanalyt197.6197.6135min+0.0297.59

This lot contributes 10 paired comparisons to the inter-lab analysis.

Section 4

The supplier's certificate for this lot

One number the supplier wrote, beside the median of the numbers other people measured on the same physical material. That comparison is only available because the index groups by lot.

FigureSupplier COAThis reportIndex note
Purity (% area)98.097.75divergence +0.25 pp vs batch median
Total impurities (% area)2.002.25
Largest single impurity (% area)1.161.22
Water (%)3.85.39
Counter-ion (%)3.62.00
Peptide content (%w/w)92.0not determined
Endotoxin (EU/mg)not stated2.04
Method stated on certificateYEScolumn, gradient and wavelength given
Section 5

Impurity fingerprint

The named impurities reported across this lot's assays, with how consistently each was seen. A fingerprint is what allows two lot numbers held by different companies to be identified as one bulk.

Named impurityReported inMedian % areaRange
free MGF (unconjugated)13 / 131.060.15–1.32
di-PEGylated species13 / 130.700.57–1.69
hydrolysed linker13 / 130.260.21–0.46
free mPEG13 / 130.150.12–0.29
Section 7

What this rollup does not establish