Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was studied
The study developed and validated a tin-in-canned-foods analytical method designed for routine monitoring in packaged beverages and canned foods. Specifically, the authors optimized a non-extractive spectrofluorimetric assay where tin(II) forms a fluorescent complex with 1-(2-pyridylazo)-2-naphthol (PAN) inside a mixed micellar medium. A blend of the non-ionic surfactant Triton X-100 and the anionic surfactant AOT was used to solubilize the otherwise water-insoluble Sn–PAN complex and intensify fluorescence. Under optimized conditions, the Sn–PAN complex was measured at 300 nm excitation and 360 nm emission after a 20-minute complexation period, with performance characterized by linear range, detection/quantification limits, precision, and interference tolerance. Because tin can leach from tinplate packaging into foods, the method is positioned as a practical quality-control tool aligned with public-health limits for tin in canned foods (the paper notes FAO/WHO guidance of 250 mg/kg and reports GI effects above ~200 mg/kg).
Who was studied?
No human participants were studied. The “subjects” were commercially relevant tin-in-canned-foods matrices and analytical test solutions: canned fruit beverages (pear nectar, mango juice, orange juice, pineapple juice) and canned fish. The authors also examined method robustness using (1) calibration standards prepared from SnCl₂·2H₂O, (2) digestion and reduction steps tailored to real samples (acid digestion followed by aluminum metal to reduce Sn(IV) to Sn(II), since Sn(IV) does not react with PAN under the described conditions), and (3) spiking/recovery experiments across multiple fortification levels to simulate contamination scenarios relevant to compliance testing. These choices mirror the types of packaged foods an HMTC-style certification program would screen, where matrix effects, oxidation state, and co-occurring ions can determine whether a method is dependable enough for pass/fail decisions.
Most important findings
For tin-in-canned-foods monitoring, the key result is that a relatively simple fluorescence workflow achieved low ng/mL detection with strong precision and acceptable selectivity in digested canned matrices, supporting surveillance against regulatory and certification thresholds.
| Critical point | Details |
|---|---|
| Sensitivity and working range support compliance screening | Calibration was linear from 0.01–0.8 µg/mL (r = 0.9991). Detection and quantification limits were 2.0 ng/mL and 6.6 ng/mL, respectively, using IUPAC definitions (3Sb/m and 10Sb/m). |
| Precision is compatible with certification-grade repeatability | The relative standard deviation was 0.74% for five same-day measurements at 0.1 µg/mL tin, indicating tight repeatability for routine QC. |
| Matrix preparation addresses oxidation state, a common failure mode | The method targets Sn(II); Sn(IV) does not react under the assay conditions. For real samples, aluminum metal was added after digestion to reduce Sn(IV) to Sn(II), preventing under-reporting when tin is oxidized during processing. |
| Accuracy demonstrated through spike recoveries across foods | Spike recoveries in juices and canned fish ranged from 95.2% to 102.8% across multiple fortification levels, supporting quantitative use in complex matrices. |
| Selectivity: most ions tolerated, but specific metals can interfere | Many common ions were tolerated at high mass ratios, but Cu(II), Co(II), Fe(II) interfered at ~1:1 and Fe(III), V(V) at lower relative levels; the authors note masking/ion-exchange approaches as mitigation strategies when needed. |
| Real-sample tin levels provide context for surveillance | Reported total tin contents (mg/kg) were ~56–78 for juices and ~109.7 for canned fish (means of three determinations), below the paper’s cited public-health limit but high enough to justify routine monitoring. |
Key implications
For tin-in-canned-foods regulation and HMTC-style certification, this method supports enforceable, lot-level monitoring because it combines low detection limits, strong repeatability, and demonstrated recovery in representative canned matrices. Certification requirements should explicitly control oxidation state handling (Sn(IV) reduction to Sn(II)), digestion consistency, and interference management for Cu/Co/Fe/V to prevent false compliance calls. Industry applications include rapid screening of canned beverages and fish for packaging-leachate tin and verification against action limits near 200–250 mg/kg. Research gaps include inter-laboratory validation, broader food categories, and comparison to reference methods (e.g., ICP-based totals). Practical recommendations are to adopt QC spikes, matrix-matched calibration checks, and documented masking/cleanup triggers when interfering metals are suspected.
Citation
Manzoori JL, Amjadi M, Abolhasani D. Spectrofluorimetric determination of tin in canned foods. J Hazard Mater. 2006;B137:1631-1635. doi:10.1016/j.jhazmat.2006.04.058
