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Thermo Fisher Scientific (China) Co., Ltd
CAD Solution Collection | New Electric Mist Detector Seamless Connection Pharmacopoeia Varieties
Date: 2025-11-05Read: 2
The seventh generation Vanquish CAD P-series electric fog detector has won widespread attention and in-depth exploration in the industry since its launch. Two core questions: Can we reproduce and optimize some pharmacopoeia varieties? Can existing CAD methods be seamlessly transferred? Answer each one for you!
1. Daguanmycin
Daguanmycin (an amino cyclic alcohol antibiotic derived from Streptomyces) has no conjugated structure and weak UV absorption, making it impossible to perform routine analysis using UV detectors. The universal CAD detector has become the preferred choice for detecting such antibiotics due to its high sensitivity and stable reproducibility.
1.1 Instruments
Thermo Scientific ™ Vanquish ™ Vanquish Core HPLC Chromatography System:
System Base:Vanquish Core (VC-S01-A-02)
Pump:Quaternary Pump CN (VC-P21-A-01)
Automatic sampler:Split Sampler C (VC-A13-A-02)
Column temperature box:Column Compartment C (VC-C10-A-03)
Detector:Vanquish Horizon CAD P(VH-D21-A-01)
Software:Chromeleon™ 7.3 CDS
1.2 Chromatographic conditions
Chromatographic column:Acclaim AmG C18，3.0×150mm，3µm(P/N：088755)
Mobile phase:0.1mol/L trifluoroacetic acid aqueous solution, isocratic elution
Current Speed:0.4mL/min
Column temperature:25℃
Injection volume:5μL
CAD detector:Evaporation temperature: 35 ℃, collection frequency: 5Hz, filtration constant: 3.6S
1.3 Experimental results
Figure 1 Determination spectrum of spectinomycin in the sample
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Figure 2 Quantitative limit map of spectinomycin
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Figure 3 Precision results of spectinomycin
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Figure 4: Linear Results of Macromycin (1-20ppm)
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The Thermo Fisher Acclaim AmG C18 column (polymer coated technology) is stable and resistant to hydrolysis in strong acid and high water phase environments, and is suitable for chromatographic conditions of 0.1 mol/L trifluoroacetic acid aqueous solution. The detection showed that the main peak and related substances of spectinomycin were completely detected and the separation degree was good; The quantification limit is 5ng (1.0ppm, S/N=11.7, 5 μ L injection), with 6 repeated injections and RSD (retention time 0.06%, peak area 0.87%). The linear R ² of 1-20ppm is greater than 0.999 (PV=1.5). This method is highly sensitive, high-precision, and has good linearity, fully meeting the detection requirements of hydrochloric acid spectinomycin.
1.4 Results and Discussion
The response value of the evaporative light scattering detector is exponentially related to the mass of the measured substance and requires logarithmic conversion; The response value and mass number of CAD detectors are mostly nonlinear and require logarithmic conversion or quadratic function calculation. In a small range (such as 1-20ppm of spectinomycin), they can exhibit linear linearity. Partial scenarios require a wide concentration range to examine linearity, combined with CAD response consistency, to accurately obtain information such as sample principal component purity.
Figure 5 shows the linear results of different PV values in the range of 1-200ppm for erythromycin (PV values are 1.5, 1.8, 2.0, 2.2 in sequence) (click to view the larger image)
Figure 6 Four channels simultaneously collecting different PV values settings
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The new CAD P series detector has a convenient PV value optimization function, which expands the linear range and reduces result deviation. Case study of spectinomycin: At concentrations of 1-200ppm, measurements of four PV values (1.5/1.8/2.0/2.2) showed that only PV=2.0 could be linearly fitted with a linear regression (R ²>0.999), while the rest were quadratic functions; When 1-600ppm, PV=2.2 is linearly optimal. In practical applications, the optimal PV value can be selected according to the concentration range to efficiently complete the content determination. The new CAD P series detection can simultaneously set 4 PV values, shorten screening time, and improve method development efficiency.
Figure 7 CAD standard switching valve
Figure 8: Sample chromatogram of spectinomycin after valve switching (click to view larger image)
CAD P series detector 3-to-1 switching valve, more flexible to set as needed. As shown in the figure: 1.6-2.6min valve cutting, cut the irrelevant matrix into waste liquid, retain hydrochloric acid spectinomycin and impurities, reduce pollution, improve instrument durability, and reduce maintenance costs. When the detector is empty/reporting an error, the valve switches to the waste liquid/bypass to avoid flooding the detector and ensure the safety of the instrument.
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2. Deoxycholic acid
From standard status to market application, deoxycholic acid has formed a stable adaptation with CAD detectors. Firstly, as a commonly tested variety of CAD, deoxycholic acid has been included and used by USP for many years, becoming the gold standard for its content and impurity detection; Secondly, with the authority of standards and the adaptability of testing, many customers have adopted CAD detectors to carry out deoxycholic acid testing work.
2.1 Instruments
Thermo Scientific ™ Vanquish ™ Flex UHPLC Chromatography System:
System Base:Vanquish Horizon/Flex (VF-S01-A-02)
Pump:Vanquish Quaternary Pump F (VF-P20-A)
Automatic sampler:Vanquish Split Sampler FT (VF-A10-A-02)
Column temperature box:Vanquish Column Compartment H (VH-C10-A-03)
Detector:Vanquish Charged Aerosol Detector HP (VH-D21-A-01)
Vanquish Charged Aerosol Detector H (VH-D20-A)
Software:Chromeleon™ 7.3.2 CDS
2.2 Chromatographic conditions
Chromatographic column:Acclaim™ 120 C18 3µm,4.6 × 150 mm (P/N 059133)
Mobile phase:A: 0.1% formic acid aqueous solution, B: 0.1% formic acid acetonitrile, gradient elution as shown in Table 1
Table 1 Gradient elution program
Current Speed:1.0mL/min
Column temperature:30 ℃, air circulation mode (fan speed 5), active preheating
Injection volume:25μL ， Injector temperature: 8 ℃
PFV values of Vanquish CAD H: 1.0, 1.2, 1.4, 1.6
PV value of Vanquish CAD HP:
CAD General Parameters:Evaporation temperature: 50 ℃, collection frequency: 20Hz, filtration constants: 2, 3.6, 5, 10s
2.3 Experimental Results
Core parameters of CAD detector: PV value (original PFV value), evaporation temperature, filtration constant. To transfer from Vanquish CAD H to Vanquish CAD HP, adjustments to these parameters need to be considered. Result: The evaporation temperature was 50 ℃, and both met the S/N requirement; The filtering constant is 5s, and both models balance noise and peak width. Please note that there is a significant difference between the PFV and PV values of the two, which needs to be verified.
Figure 9 Linear and residual results of different PV values of CAD HP deoxycholic acid
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Figure 10: Linear and Residual Results of CAD H Deoxycholic Acid with Different PFV Values
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To compare the linear performance of deoxycholic acid, the PFV values of Vanquish CAD H were set to 1.0, 1.2, 1.4, and 1.6, and the PV values of Vanquish CAD HP were set to 1.5, 1.8, 2.1, and 2.4, respectively, to investigate the linear relationship within the concentration range of 0.5-10 μ g/mL. The experimental results show that Vanquish CAD H (PFV=1.2) and Vanquish CAD HP (PV=1.8) can achieve the best linear results, R²=1.00； And both residuals are randomly distributed near the zero line (y=0), verifying the fitting effectiveness of the selected linear model.
Figure 11 CAD chromatogram and system adaptability results of deoxycholic acid (n=10) (click to view large image)
System applicability results: When deoxycholic acid is 0.01mg/mL, the RSD of peak area for both CAD detectors is less than 3.0%; When the concentration is 0.0005mg/mL, the S/N ratio is>10, indicating that the sensitivity meets the standard. Both meet the requirements of USP method for determining deoxycholic acid.
2.4 Results and Discussion
Figure 12 Seamless Transfer in Legacy Mode (Click to View Large Image)
From mode functionality to method transfer, the Vanquish CAD P series forms a complete solution: ① Mode selection: Easy (single channel PV), Advanced (4-channel efficient filtering), Legacy (automatic conversion of old PFV); ② Conversion logic: PFV × 1.5=new PV, deoxycholic acid case (1.2 → 1.8) is consistent with experimental data; ③ Core value: Safe conversion of old parameters, convenient and efficient method transfer, and reduced operating costs.
Summary
The Vanquish CAD P electric mist detector is designed for the detection scenario of hydrochloric acid spectinomycin in the 2025 edition of the Chinese Pharmacopoeia. It accurately overcomes the core pain points of low sensitivity and poor repeatability of evaporative light scattering detectors (ELSD), obtaining wider linearity with one click and minimizing result deviation, significantly improving the applicability of pharmacopoeia methods and ensuring durability when switching valves. Deoxycholic acid USP method for easy transfer, worry free for customers!
References:
[1] Chinese Pharmacopoeia 2020 Edition, Part 2: Macromycin Hydrochloride
[2] Research on the Method of AN_25052-HPLC High Performance Liquid Chromatography with Electric Mist Detector for the Detection of Macromycin
[3] The United States Pharmacopoeia[M]. The United States Phar macopeial Convention, 2016.
[4] TN_3816 Method transfer and optimization of deoxycholic acid analysis using HPLC-CAD