Table 2.
Spectrophotometric methods for determining adulterated drugs in herbal medicine.
| Analyte | Matrix | Method | Max Wavelength or Frequency | LOD/LOQ | %RSD/Recovery | Reference |
|---|---|---|---|---|---|---|
| Dexamethasone | Herb claimed for joint painkiller * | Infrared spectroscopy combined with partial least square (PLS) |
Wavenumbers 3646, 3642, 2461, 2453, 2432, 2406, 2229, 2209, 2197, 2097, 2092, 2064, 2059, 2047, 2026, 2009, 1969, and 1513 cm−1 | - | Validation: R2 = −0.9988 RMSEC = 0.009455 PRESS = 0.0022721 RMSECV = 0.02902 |
[10] |
| Sildenafil | An herbal product claimed to enhance sexual activity * | FTIR-SMLR Stepwise multiple linear regression |
wavenumbers 1791, 1692, 1691 and 971 cm−1 | - | Validation: R2 = 1.00 RMSEC = 0.000310913 PRESS = 0.0009191 |
[11] |
| Sibutramine, phenolphtalein |
Capsule, tablet, powder for weight-loss | Low-field 1H NMR spectroscopy | Frequency = 59.7 mHz for 1H | Lowes limit 3 mg/100 mg | - | [5] |
| Rutin, quercetin, kaempferol | Capsule and tablet containing Ginkgo biloba |
FTIR-PLS DA | Wavelength = 900–1800 cm−1 | - | Validation RMSEC = 0.393 RMSECV = 0.570 |
[36] |
| Ephedrin, pseudoephedrine | Slimming herbal product | 2DCOS | Wavelength: 4000–400 cm−1 | LOD = <1% | - | [37] |
| Melatonin, doxepin, diazepam, chlorpheniramine, zopiclone, nitrazepam, zaleplon, alprazolam, clonazepam and chlordiazepoxide |
Herbal dietary supplements (pills, tablets, capsules, or soft-gel capsules) | WT-ESI-MS | Tranquilizer and aphrodisiac samples = 230 nm Weight loss samples = 225 nm or 265 nm. |
LOD = 0.1 mg/g | - | [39] |
| Paracetamol, naproxen, sulfamethoxazole, diclofenac, and phenylbutazone |
Tablet and capsules (anti rheumatism health care products) | Fast-switching +/− HV tip-ESI--MS |
- | LOD: (<0.1 ng/g) PCM = 0.05 ng/g NPX 0.1 ng/g for NPX, 0.01 ng/g for SMZ, 0.01 ng/g for DCM, and 0.1 ng/g for PBZ |
- | [40] |
| Nifedipine, nisoldipine, nicardipine, lercanidipine, felodipine, clevidipine, metformin hydrochloride, lovastatin, Simvastatin, gemfibrozil, and fenofibrate | Tablets, pills, granules, and capsules | UEN/CFI-MS | - | LOD = 2 mcg/g to 50 mcg/g | RSD = less than 15% | [41] |
* The detailed herbal matrices available in the article.