Analysis of toxic and nutrient elements in hops by NexION ICP-MS

Introduction

Plants are an important source of food nutrition, but toxic elements can also be found in them, mainly from soil, water and fertilizer during their growth. Therefore, it is important to determine the content of nutrients and toxic elements in plant materials. There are many challenges in elemental analysis in plants. First, in order to improve production efficiency, it is usually required to simultaneously measure toxic elements and nutrient elements, thus requiring a large dynamic range; and plants are complex biological entities that require sample preparation before testing can be performed. It is usually first homogenized by the sample and then digested to decompose the complex matrix and extract the elements. Plant samples Despite the above steps, matrix-induced spectral interference can still occur in ICP-MS detection, which can lead to data deviations and even errors, especially for low-level toxic elements. Therefore, collision / reaction cell technology can be used to better eliminate interference.

The current cultivation and use of cannabis has caused widespread concern in the United States. Several states have declared the legalization of marijuana, which can be used for both entertainment and medical purposes through both food intake and food intake. Therefore, there is an increasing concern about its toxic and mineral content.

Another challenge in cannabis analysis in the United States is the legal acquisition of samples, after which marijuana is not legal in some states. However, hops are a generally accepted alternative to cannabis due to their similar chemical and physical properties.

This article discusses toxic elements and nutrients in hops using ICP-MS as a substitute for cannabis.

experiment

Sample Preparation

Hops are purchased from a store and chopped to make them uniform and surface area increased to improve digestion efficiency. The Titan MPSTM microwave sample preparation system equipped with a standard 75 mL PTFE (polytetrafluoroethylene) digestion tank was used for digestion according to the digestion procedure in Table 1 . Each digestion tank contains 0.25 g of plant material sample, 5.0 mL of concentrated nitric acid, 5.0 mL of deionized water, and 3.0 mL of 30% hydrogen peroxide. After the digestion is complete, dilute the sample with deionized water until
50 mL, was added while the gold (Au) to stabilize the mercury (final solution contained 200 μ g / L Au).

Instrument condition

All analyses were performed on a PerkinElmer NexION® ICP-MS equipped with standard injection components .
The elements of the assay and the analytical modes used are shown in Table 2 . Add the internal standard online by mixing the tee. The final concentration of the instrument injection was 10 mg/L Sc , 5 mg/L Ge, and 0.1 mg/L Rh , In , Tb , 10% methanol, and 1% nitric acid. The combination of standard and collision modes results in an analysis time of only 100 seconds per sample .

Results and discussion

Table 3 shows the average results of two hop sample digestions. In order to verify the accuracy, the elements before the digestion are spiked for elements with a content of less than 50 mg/kg . The spiked concentration of all elements was 20 mg/L and the spiked concentration of Hg was 2 mg/L . All spiked recoveries were within 15% of the added amount , further confirming the accuracy of the method.

in conclusion

This work proves that NexION ICP-MS combined with Titan MPS microwave system can effectively analyze the nutrients and toxic elements in hops that can be used as a substitute for cannabis. The analysis uses collision and standard modes, and each sample analysis takes only 100 seconds. The accuracy of the applied method was verified by analyzing various NISTTM standard plant materials.

references

1. Bosnak, C., Pruszkowski, E., “The Determination of Toxic, Essential, and Nutritional Elements in Food Matrices Using the NexION 300/350 ICP-MS”, PerkinElmer Application Note.

Related instruments: NexION® 1000G ICP-MS

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