Table 1.
Validation parameters calculated for determination of sulphonamides in honey and beeswax samples (n = 18)
| Honey | Beeswax | |||||
|---|---|---|---|---|---|---|
| Sample | Concentration (μg/kg) | Recovery (%) | Intermediate precision (CV, %) | Concentration (μg/kg) | Recovery (%) | Intermediate precision (CV, %) |
| SCA | 2 | 69.7 | 15.1 | 1,000 | 71.9 | 12.7 |
| 25 | 68.1 | 14.9 | 5,000 | 73.1 | 14.6 | |
| 100 | 72.4 | 16.6 | 10,000 | 69.1 | 13.2 | |
| SDA | 2 | 96.7 | 12.9 | 1,000 | 98.2 | 11.4 |
| 25 | 98.4 | 11.7 | 5,000 | 99.2 | 12.3 | |
| 100 | 99.3 | 13.2 | 10,000 | 97.7 | 12.9 | |
| STZ | 2 | 93.3 | 13.4 | 1,000 | 98.9 | 10.4 |
| 25 | 93.2 | 11.8 | 5,000 | 99.1 | 12.3 | |
| 100 | 94.2 | 14.2 | 10,000 | 97.2 | 10.9 | |
| SMR | 2 | 97.2 | 14.8 | 1,000 | 97.4 | 10.1 |
| 25 | 99.7 | 13.2 | 5,000 | 98.6 | 10.9 | |
| 200 | 98.3 | 14.6 | 10,000 | 97.7 | 12.3 | |
| SMZ | 2 | 97.4 | 11.9 | 1,000 | 99.1 | 12.9 |
| 25 | 99.7 | 13.2 | 5,000 | 98.6 | 10.4 | |
| 200 | 98.1 | 12.8 | 10,000 | 99.7 | 12.1 | |
| SMT | 2 | 98.0 | 12.3 | 1,000 | 97.1 | 11.7 |
| 25 | 96.7 | 11.1 | 5,000 | 98.5 | 13.2 | |
| 200 | 99.3 | 12.8 | 10,000 | 97.9 | 10.5 | |
| SMM | 2 | 96.9 | 13.7 | 1,000 | 99.9 | 12.1 |
| 25 | 98.0 | 12.9 | 5,000 | 97.0 | 10.3 | |
| 200 | 99.6 | 14.1 | 10,000 | 99.1 | 12.2 | |
| SDX | 2 | 97.0 | 10.4 | 1,000 | 98.2 | 13.2 |
| 25 | 99.9 | 11.2 | 5,000 | 97.9 | 11.5 | |
| 200 | 98.3 | 10.7 | 10,000 | 99.7 | 13.3 | |
| SMX | 2 | 96.1 | 14.5 | 1,000 | 98.0 | 11.8 |
| 25 | 97.8 | 13.8 | 5,000 | 96.6 | 11.9 | |
| 200 | 99.7 | 13.2 | 10,000 | 98.8 | 12.8 | |
| SDM | 2 | 95.6 | 15.9 | 1,000 | 96.3 | 12.9 |
| 25 | 94.2 | 13.2 | 5,000 | 99.3 | 12.6 | |
| 200 | 97.8 | 15.2 | 10,000 | 97.0 | 10.2 | |
Table 2.
The concentrations and recoveries of sulphonamides calculated for the beeswax foundation fortified with 10 sulphonamides at 10,000 μg/kg (n = 4)
| Analyte | Concentration (μg/kg) | Recovery (%) | Analyte | Concentration (μg/kg) | Recovery (%) |
|---|---|---|---|---|---|
| SDM | 4,625 ± 287 | 46 | SMR | 4,358 ± 260 | 44 |
| SMM | 5,326 ± 399 | 53 | SDA | 5,027 ± 318 | 50 |
| SDX | 4,541 ± 383 | 45 | SMT | 1,993 ± 156 | 20 |
| SMX | 3,824 ± 406 | 38 | SCA | 4,409 ± 370 | 44 |
| SMZ | 4,138 ± 152 | 41 | STZ | 3,072 ± 236 | 31 |
Table 3.
The maximum transfer (%) of sulphonamides from tainted beeswax to the honey stored in the comb
| Analyte | The maximum transfer (%) of sulphonamides | |||||
|---|---|---|---|---|---|---|
| 1 month | 2 months | 3 months | 4 months | 5 months | 6 months | |
| SDM | 13.2 | 15.7 | 21.1 | 42.6 | 20.4 | 9.9 |
| SDX | 10.3 | 13.4 | 17.9 | 34.3 | 18.3 | 8.1 |
| SMM | 10.0 | 11.5 | 15.8 | 31.7 | 14.9 | 6.9 |
| SMX | 7.9 | 9.3 | 13.9 | 30.1 | 13.5 | 5.1 |
| SMT | 8.4 | 12.3 | 17.7 | 29.5 | 18.6 | 9.0 |
| SMZ | 8.2 | 9.6 | 13.6 | 25.2 | 12.3 | 5.8 |
| SMR | 6.2 | 7.0 | 10.6 | 18.7 | 9.7 | 4.2 |
| SDA | 4.5 | 5.6 | 8.6 | 16.1 | 8.4 | 3.9 |
| STZ | 2.2 | 3.2 | 5.6 | 9.5 | 6.4 | 2.3 |
| SCA | 3.6 | 5.0 | 7.8 | 8.6 | 8.5 | 4.0 |
1 SDM – sulphadimethoxine; SDX – sulphadoxine; SMM – sulphamonomethoxine; SMX – sulphamethoxazole; SMT – sulphameter; SMZ – sulphamethazine; SMR – sulphamerazine; SDA – sulphadiazine; STZ – sulphathiazole; SCA – sulphacetamide. Combs were completely filled with honey on both sides, thus the ratio of honey (2,448 g) to beeswax (110 g) at each sampling point on the comb was always 22.25 : 1
Fig. 1.
Concentrations of sulphadimethoxine (SDM), sulphamonomethoxine (SMM), sulphadoxine (SDX), sulphamethoxazole (SMX), sulphamethazine (SMZ), sulphamerazine (SMR), sulphadiazine (SDA), sulphameter (SMT), sulphacetamide (SCA) and sulphathiazole (STZ) in honey sampled from a comb drawn out on a wax foundation contaminated with these antimicrobials at 4,625, 5,326, 4,541, 3,824, 4,138, 4,358, 5,027, 1,993, 4,409 and 3,072 μg/kg, respectively (n = 4)
Table 4.
Predicted pKa and lipophilicity of sulphonamides
| Analyte | pKa1a pKa2b | % particles in the unionised form at pH 4.2 | logP | Analyte | pKa1a pKa2b | % particles in the unionised form at pH 4.2 | logP |
|---|---|---|---|---|---|---|---|
| SDM | 1.95 6.91 | 99.3 | 1.26 | SMZ | 2.00 6.99 | 99.2 | 0.65 |
| SDX | 2.11 6.12 | 98.0 | 0.58 | SMR | 2.00 6.99 | 99.2 | 0.52 |
| SMM | 2.17 7.15 | 99.0 | 0.74 | SDA | 2.01 6.99 | 99.2 | 0.39 |
| SMX | 1.97 5.86 | 97.3 | 0.79 | STZ | 2.04 5.73 | 96.4 | 0.98 |
| SMT | 1.98 7.06 | 99.3 | 0.23 | SCA | 2.14 5.60 | 95.3 | -0.26 |