Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
ISO 29943-1:2017 — Guidance on Measurement of Nitrosamines from Condoms — Part 1: Artificial Sweat Extraction
Expanded guidance for N-nitrosamine determination using artificial sweat extraction | GC-TEA method validation | Laboratory quality control
1. Purpose and Scope of ISO 29943-1
ISO 29943-1:2017 provides detailed guidance on the measurement of N-nitrosamines released from condoms using an artificial sweat extraction procedure. While ISO 29941 establishes the reference method, this standard offers expanded procedural guidance for laboratories performing routine compliance testing. The document addresses common sources of variability in nitrosamine measurement and provides recommended practices for method validation, quality control, and data interpretation.
Key Application: ISO 29943-1 is particularly valuable for laboratories establishing nitrosamine testing capabilities for the first time, as it provides step-by-step guidance on extraction cell preparation, solvent handling, and instrument setup that supplements the more concise ISO 29941.
2. Artificial Sweat Extraction Procedure
The extraction procedure uses an artificial sweat formulation that closely matches human perspiration composition. The sweat solution contains sodium chloride, lactic acid, and urea at controlled pH. The condom sample is placed in an extraction cell with a known volume of artificial sweat and incubated at 40 ± 1 °C for 4 hours with continuous agitation. After extraction, the solution undergoes SPE cleanup using a two-stage column configuration.
| Step | Parameter | Acceptance Criteria |
|---|---|---|
| Sample preparation | Surface area ≥ 100 cm² | ± 2 % measurement accuracy |
| Extraction volume | 50 mL artificial sweat | Pre-warmed to 40 °C |
| Incubation | 40 ± 1 °C, 4 h | Continuous orbital shaking at 100 rpm |
| SPE conditioning | 5 mL methanol, 5 mL water | Flow rate ≤ 3 mL/min |
| Elution | 5 mL dichloromethane | Collect in graduated tube |
Critical Control Point: The pH of artificial sweat must be verified before each extraction series. pH drift above 6.8 significantly increases nitrosamine migration rates, leading to falsely elevated results and potential non-conformities.
3. Method Validation Requirements
The standard recommends a comprehensive validation protocol including linearity (r² ≥ 0.995 over the calibration range), precision (RSD ≤ 15 % at the limit of quantification), recovery (70-120 %), and measurement uncertainty estimation. Matrix effects must be evaluated by standard addition experiments, and laboratory control samples should be analyzed with each batch at a frequency of at least 5 %.
4. Frequently Asked Questions
Q1: How does ISO 29943-1 differ from ISO 29941?
A: ISO 29943-1 provides expanded procedural guidance and troubleshooting advice, while ISO 29941 focuses on the core method specification. Both use artificial sweat extraction.
A: ISO 29943-1 provides expanded procedural guidance and troubleshooting advice, while ISO 29941 focuses on the core method specification. Both use artificial sweat extraction.
Q2: What type of agitation is recommended?
A: Orbital shaking at 100 rpm is preferred. Ultrasonic agitation is not recommended as it may cause mechanical degradation of the latex and artifactually increase nitrosamine release.
A: Orbital shaking at 100 rpm is preferred. Ultrasonic agitation is not recommended as it may cause mechanical degradation of the latex and artifactually increase nitrosamine release.
Q3: Can the same calibration standards be used for GC-TEA and GC-MS/MS?
A: Yes, but matrix-matched calibration is recommended for GC-MS/MS to account for ion suppression or enhancement effects.
A: Yes, but matrix-matched calibration is recommended for GC-MS/MS to account for ion suppression or enhancement effects.
