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preparation required. This enables onsite analysis at a tea production facil- ity to rapidly identify contaminants such as medications and agricultural product residues. In this case, tea samples were spiked, but this analysis represents the ability of the analyzer to separate nonnative tea compounds from contaminants, such as agricultural and pharmaceutical products.


In another application, the analyzer was used to achieve high-resolution separation of a complex mixture of seven pesticides (Figure 3), simulating analysis that can be performed onsite at a quality control facility in the agri- culture industry. Peaks were well separated and distributed uniformly along 8 minutes of analysis time and using less than 2 mL of acetonitrile. Despite the structural similarities of some of the analytes, i.e., 4-chlorophenoxyace- tic acid and 2,4-dichlorophenoxyacetic acid, in particular, the analyzer was able to achieve 4 minutes of separation between these compounds using the Primesep D reversed-phase column (SIELC Technologies).


Analysis of food dyes in consumer products The Alltesta analyzer provides rapid (<3 minute) analysis of food dyes commonly used in products in the beverage and pharmaceutical indus- tries. Allura Red (Red #40) was quantified in both soft drinks (Figure 4a) and over-the-counter drugs (Figure 4b) using the analyzer equipped with an Obelisc N mixed-mode column (SIELC Technologies). Minor differences in Allura Red AC concentration were detected in the samples tested. Ammonium formate was employed in a low-concentration gradient in both cases to ensure fast separation and LC/MS compatibility.


Figure 3 – High-resolution separation of seven pesticides in a mixture: 1) dichloran, 2) folpet, 3) azinphos-ethyl, 4) 4-chloro-phenoxyacetic acid, 5) mecoprop, 6) triclopyr, 7) 2,4-dichlorophenoxyacetic acid. Column: Primesep D, 3.2 × 50 mm; mobile phase: 35% MeCN, 0.30% H3


PO4 ; flow


rate: 0.6 mL/min; detection: 270 nm; sample preparation: 1 mg/mL in 1:1 MeCN:water.


Analysis of prescription and over-the-counter (OTC) drugs Separation of prescription antibiotics is shown in Figure 5. As with the anal- ysis of pesticides in Figure 3, some of the analytes, namely sulfaguanidine and sulfanilamide, resemble each other structurally, yet separation was


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