Ultratraces of carotenes in tomato purées: HPLC-TLS study

Abstract

The present study was designed to provide information about ͑i͒ the profile of carotene pigments and ͑ii͒ trace quantities of lycopene and ␤-carotene left in tomato purées. The ultrasensitive method comprising HPLC and thermal lens spectrometric ͑TLS͒ detection enabled us to detect as low as 0.3 and 1.1 ng ml Ϫ1 lycopene and ␤-carotene in purée extracts, respectively. Total concentration of ␤-carotene and lycopene ͑varying from 3 to 170 ng g Ϫ1 ) in the examined tomato purées may serve as an indicator of the carotene-specific antioxidative capacity of these products. Although conventional spectrophotometry can be used to rapidly assess the quality of products derived from tomatoes, a highly sensitive and selective method such as HPLC-TLS is needed for reliable analyses of samples such as, for example, those subjected to inappropriate storage and/or handling.

Separation and Direct Detection of Long Chain Fatty Acids and their Methylesters by the Non‐Aqueous Reversed Phase HPLC and Silver Ion Chromatography, Combined with CO Laser Pumped Thermal Lens Spectrometry

“…The relatively high IR background absorption of the mobile phases used in our experiments precludes, at least for the time being, NARP-HPLC-TLS and Ag-HPLC-TLS detectors from achieving spectacular sensitivities already obtained with the same technique in the visible region when quantifying trans-beta-carotene in human blood serum [29] and fish oil based supplementary drugs, [30] detecting carotenoids in the edible oils [31] and determining the content of lycopene in tomato purees. [32] A more judicious selection of the mobile phase could compensate for this effect; however, the choice of weakly absorbing and polar eluents that are also capable of achieving good chromatographic separation may be limited. [33] …”

On the photoacoustic, photothermal and colorimetric quantification of carotenoids and other phytonutrients in some foods: a review

“…By combining coaxial DBTLS with a reverse phase HPLC system, it was possible to detect as little as 0.3 and 1.1 ng/ml lycopene and beta-carotene, respectively, in extracts of tomato purees [32]. The total concentration of beta-carotene and lycopene (varying from 3 to 170 ng/g) in the investigated purees can be regarded as indicative for the assessment of carotene-specific antioxidative capacity.…”

Quantification of lycopene in tomato products: comparing the performances of a newly proposed direct photothermal method and high‐performance liquid chromatography

“…Likewise, Luterotti et al 19 recently studied lycopene in tomato purées and reported a good correlation (R 2 = 0.85) between data acquired by conventional spectrophotometry and those obtained by HPLC combined with thermal lens spectrometry as a novel methodology to measure the absorbance.…”