Rapid detection of illegal colorants on traditional Chinese pastries through mass spectrometry with an interchangeable thermal desorption electrospray ionization source

Rhodamine and related substances in food: Recent updates on pretreatment and analysis methods

Rhodamine, a colorant prohibited in various consumer products due to its demonstrated carcinogenic, mutagenic, and toxic properties, necessitates the development of a straightforward, efficient, sensitive, environmentally friendly, and cost-effective analytical method. This review provides an overview of recent advancements in the pretreatment and determination techniques for rhodamine across diverse sample matrices since 2017. Sample preparation methods encompass both commonly used pretreatment techniques such as filtration, centrifugation, solvent extraction, and cloud point extraction, as well as innovative approaches including solid phase extraction, dispersive liquid-liquid microextraction, hollow fiber liquid phase microextraction, magnetic solid phase extraction, and matrix solid phase dispersion. The analytical techniques encompass high performance liquid chromatography, surface-enhanced Raman scattering, and sensor-based methods. Furthermore, a comprehensive examination is conducted to offer insights for future research on rhodamine regarding the advantages, disadvantages, and advancements in various pretreatment and determination methodologies.

Application of sodium bicarbonate in extraction and determination of synthetic colorant in processed grain products

As the only standard of its kind, GB5009.35-2016 provides the determination of water-soluble synthetic colorants in processed grain products with high starch content for the purpose of food safety risk monitoring. However, it's only applicable to candy products and liquid foods as beverages, but not solid grain products. Extraction is a critical and essential step in the overall analytical process for determination. This paper provides an improved method for extraction of synthetic colorants in food products presenting high starch content. The samples were successively extracted with methanol-water (4:6, v/v) containing 2.7% sodium bicarbonate, and the target analytes were purified by solid phase extraction column. The obtained eluent was concentrated in constant volume, separated by ODS-SP C18 column and determined by diode array detector. The limits of detection were in the range of 2.21 ~ 8.62 ng/mL for 6 synthetic colors. The average recoveries at the spiked levels of 10, 30, 50 μg/kg varied in the range of 79.3 ~ 101.4% with RSD (n = 6) around 0.2 ~ 6.7%. The developed sodium bicarbonate based extraction method was successfully applied to speciation analysis of water soluble azo synthetic colorant in starchy food, such as millet, grits, brown rice, rice flour, cornmeal and cornflakes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05199-x.

Rapid Screening of β-agonists in Animal Hair by Thermal Desorption Electrospray Ionization Mass Spectrometry

BACKGROUND

Even though the usage of β-agonists in livestock has been banned in many countries, β-agonists abuse is still out of control towing to the time-consuming and complicated determination technique.

OBJECTIVE

This study applied ambient thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS) as a new strategy for rapidly screening 7 β-agonists. As it does not require pretreatment, this method allows in-site and real time detection.

METHODS

Samples were collected directly using a simple metal probe. Analytes on the probe were desorbed and ionized in TD-ESI, after which analyte ions were detected using a triple quadrupole mass analyser.

RESULTS

The results showed that thermal desorption temperature of 320 °C and nebulizer pressure of 3 psi demonstrated the highest sensitivity. Excellent linear relationships were obtained in concentrations ranging from 10 to 400 μg/kg. The limit of detection of the method was 1-10 μg/kg with relative standard deviation of 7.2%-14.6%. A positive sample was verified using high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry, consistent with the results from TD-ESI/MS.

CONCLUSIONS AND HIGHLIGHTS

This method was the first to apply TD-ESI/MS to rapid analyse β-agonists in livestock hair which was proven to be accurate, fast and environmentally friendly. Because qualitative screening for each analysis was completed within approximately 1 min, it seems to contribute to prevent non-compliance animal-derived food flowing into the market.

Miniaturized sample preparation techniques and ambient mass spectrometry as approaches for food residue analysis

Analytical methods such as liquid chromatography (LC) and mass spectrometry (MS) are widely used techniques for the analyses of different classes of compounds. This is due to their highlighted capacity for separating and identifying components in complex matrices such food samples. However, in most cases, effective analysis of the target analyte becomes challenging due to the complexity of the sample, especially for quantification of trace concentrations. In this case, miniaturized sample preparation methods have been used as a strategy for analysis of complex matrices. This involves removing the interferents and concentrating the analytes in a sample. These methods combine simplicity and effectiveness and given their miniaturized scale, they are in accordance with green chemistry precepts. Besides, ambient mass spectrometry represents a new trend in fast and rapid analyses, especially for qualitative and screening analysis. However, for complex matrix analyses, sample preparation is still a difficult step and the miniaturized sample preparation techniques show great potential for an improved and widespread use of ambient mass spectrometry techniques. . This review aims to contribute as an overview of current miniaturized sample preparation techniques and ambient mass spectrometry methods as different approaches for selective and sensitive analysis of residues in food samples.

Simultaneous Determination of Synthetic Food Dyes Using a Single Cartridge for Preconcentration and Separation Followed by Photometric Detection

A novel preconcentration/separation method for simultaneous sorption-spectrophotometric determination of anionic food dyes Sunset Yellow and Tartrazine is proposed. The method is based on preconcentration of the dyes using solid phase extraction on a cartridge filled with silica chemically modified with C16 groups from aqueous solution at pH 1 followed by elution with water/acetonitrile mixture containing 2 mmol·L−1 KH2PO4 adjusted to pH 3 with a step gradient of acetonitrile content. This elution allows quantitative separation of the dyes which makes their individual spectrophotometric determination possible. The detection limits for Tartrazine and Sunset Yellow are 0.15 and 0.11 μg·mL−1 and the linearity range is 2–20 μg·mL−1. The method is applied for analysis of beverages. The recovery of dyes is higher than 97% at the relative standard deviation not exceeding 10%.

Using ambient mass spectrometry and LC–MS/MS for the rapid detection and identification of multiple illicit street drugs

In this study the recently developed technique of thermal desorption electrospray ionization/mass spectrometry (TD–ESI/MS) was applied to the rapid analysis of multiple controlled substances. With the reallocation of mass spectral resources [from a standard ESI source coupled with liquid chromatography (LC) to an ambient TD–ESI source], this direct-analysis technique allows the identification of a wider range of illicit drugs through a dual-working mode (pretreatment-free qualitative screening/conventional quantitative confirmation). Through 60-MRM (multiple reaction monitoring) analysis—in which the MS/MS process was programmed to sequentially scan 60 precursor ion/product ion transitions and, thereby, identify 30 compounds (two precursor/product ion transitions per compound)—of a four-component (drug) standard, the signal intensity ratios of each drug transition were comparable with those obtained through 8-MRM analysis, demonstrating the selectivity of TD–ESI/MS for the detection of multiple drugs. The consecutive analyses of tablets containing different active components occurred with no cross-contamination or interference from sample to sample, demonstrating the reliability of the TD–ESI/MS technique for rapid sampling (two samples min⁻¹). The active ingredients in seized drug materials could be detected even when they represented less than 2 mg g⁻¹ of the total sample weight, demonstrating the sensitivity of TD–ESI/MS. Combining the ability to rapidly identify multiple drugs with the “plug-and-play” design of the interchangeable ion source, TD–ESI/MS has great potential for use as a pretreatment-free qualitative screening tool for laboratories currently using LC–MS/MS techniques to analyze illicit drugs.