Caffeine 20-second test
No consumables are required, and caffeine, chlorogenic acid and ochratoxin can be detected
The measurement technology is based on the spectral architecture
The spectrometer has a light source. The light is transmitted through the optical fiber. The light passes through the cuvette. The test liquid is placed in the cuvette. The degree of light absorption of the test liquid is determined. The degree of light absorption is detected by the spectrometer. The result is read by the computer to obtain the absorption spectrum of the test object, and then the concentration is determined by the absorption spectrum.
The caffeine rapid test reduces the size of the spectrometer structure and uses aluminum fixtures to fix the light source and sensor. A fixed light path is created between the aluminum fixtures, and there are detection holes between the light paths. Quartz plates are placed in the detection holes, and the test liquid is between the quartz plates. The quartz plates are like colorimetric dishes. Signal judgment and calculation are performed through a microprocessor.
Limitations of use of Caffeine Quick Test
This is the spectrum of coffee diluted 30 times. Because of direct measurement, the deuterium lamp light source cannot penetrate the coffee, and it cannot be analyzed.
The caffeine quick screen uses a quartz plate to clamp the coffee, which acts like dilution, so the user can measure directly after dripping.
Four light sources are used: 280nm for caffeine, 320nm for chlorogenic acid, and the remaining two are for calibration. Although there is also trigonelline at 245nm, 245nm will produce ozone, which will damage the circuit, so it is not used.
The wavelength of 280nm for caffeine is the same as the wavelength for determining caffeine using HPLC as mentioned in the Method for Testing Caffeine in Beverages (MOHWA0028.00) announced by the Food and Drug Administration of the Ministry of Health and Welfare.
The caffeine rapid test mainly uses the measurement method of the spectrometer as the judgment principle. It is a rapid screening device. Because it is based on the principle of the spectrometer, it has some limitations, as explained below:
1. Unable to measure when the temperature of the liquid to be tested is too high:
Because the molecules and atoms in the liquid will move and vibrate at different speeds at different temperatures, this phenomenon will cause signal differences, so it is not recommended to measure at high temperatures. You can put it in a small cup and return it to room temperature, or use room temperature drinking water to dilute the test liquid, and multiply the dilution factor after the measurement.
2. For low-caffeine coffee, you must establish your own judgment formula:
If you need to measure low caffeine, we can help you create low caffeine caffeine and chlorogenic acid judgment options.
The caffeine rapid test can quickly screen the caffeine and chlorogenic acid in the coffee brewed on site. It can be clearly seen from the figure that the spectra of caffeine/chlorogenic acid of different concentrations vary greatly, and the caffeine rapid test can easily judge, but the spectrum of low-caffeine coffee is similar to the spectrum of coffee with lower concentration.
If low-caffeine measurement is used, the data that appears will be the same as the low-concentration coffee data. Although the caffeine absorption spectrum of low-caffeine drifts to 290nm, the half-wave width of the LED is about 15~20nm, so it is impossible to judge low-caffeine beverages.
3. Measure the linearity of caffeine, currently set within 120mg/100mL:
If the measured data shows 0 mg/100mL, the screen will display "out of range". Please dilute the test solution.
It is set within 120mg/100mL to increase stability. The sensor has an output voltage, which corresponds to the caffeine measurement concentration. Although the measurement range can be very wide, the operation of rapid screening equipment is not like laboratory instruments. It needs to remove impurities and operate delicately, so the signal will jump. When the signal jumps, it corresponds to the detection result. As shown in the figure, the output voltage and concentration performance, so the measurement range is deliberately set to within 120mg/100mL.
