1) British blue ultrafiltration ™
1. Application of British Blue Ultrafiltration
The requirements for the samples analyzed by ion chromatography are very strict, and the samples must not contain particulate matter, as these particles will clog and ultimately damage the separation column. If the analyzed sample contains small particles that are difficult to remove, using blue ultrafiltration is a good choice. In the process of treating beverages, surface water, wastewater, and digestion solutions, the use of English blue ultrafiltration technology can effectively protect the separation column and reduce interference to zero.
2. The difference between English blue ultrafiltration and ordinary online filtration
Nowadays, there are also some automatic samplers that integrate filtering function. The method is very simple, such as putting a disposable filter membrane on each sample tube or on the sampling needle. This method does indeed achieve filtering function, but the actual effectiveness is mediocre because it is cumbersome and the effect is questionable. We not only need to prepare filter membranes for each sample, but also need to consider the quality of the filter membranes. In fact, except for a few brands whose filter membrane quality is up to standard, most filter membranes have more or less residual anions and cations, which affects the detection effect. The price of filter membranes that meet the requirements is often astonishing, and not all laboratories can afford it when there are a large number of samples to be tested.
What are the unique features of Yinglan ultrafiltration
The uniqueness of Yinglan ultrafiltration lies in the integration of a specialized ultrafiltration module on the robot sample processor. The module design of this ultrafiltration is very special. The internal filter membrane is in the shape of a pipeline and arranged in a spiral shape. When the sample flows through the spiral pipeline, only a part of the sample completes ultrafiltration through the filter membrane. At this time, the direction of ultrafiltration is perpendicular to the flow of the sample liquid, and the entire liquid maintains 80% fluidity. In this parallel flow ultrafiltration process, residues on the surface of the filter membrane are continuously carried away, so there is no risk of clogging or rupture of the filter membrane.
Moreover, the robot sample processor can automatically clean the entire ultrafiltration unit and rinse it with the next sample, with a very low possibility of cross contamination. Therefore, the filter membrane in the ultrafiltration unit can complete 40-400 ultrafiltration processes before replacement, with an average cost of only about 0.2 yuan per ultrafiltration. The robot sample processor can complete the entire ultrafiltration and injection process. In addition, it also avoids external contamination and instability caused by general disposable filter membranes, without the need to test each purchased filter membrane for unknown issues such as residue.
4. Application examples of English blue ultrafiltration:
The Yinglan ultrafiltration technology is suitable for direct injection analysis of low load samples, such as drinking water, surface water, process water, wastewater, extracts, digestive juices, and diluted fruit juices.
The attached figure shows the spectrum of anions in fruit juice analyzed by direct injection of English blue ultrafiltration. Using a NaHCO3/Na2CO3 eluent system with a concentration of 1.7/1.8 mmol/L, the sample was diluted 100 times and directly placed in an automatic sampler for anion detection. In fact, if British blue ultrafiltration is combined with British blue dilution, even the sample dilution step can be automatically completed.
The attached figure uses A Supp 4-250 separation column, which can accurately quantify Cl? NO3? HPO42? SO42?， For the detection of industrial wastewater and urban sewage, the use of English blue ultrafiltration is also a very fast and accurate technique, as peaks 1 and 2 represent organic acids that cannot be separated and require specialized organic acid columns for separation.
2) British blue dialysis ™
Compared with blue ultrafiltration, the matrix of the analyte in blue dialysis is more complex. For example, the following substances are almost impossible to directly inject for analysis using conventional methods:
Environment: high load wastewater, high load sewage, soil and filter extract, solid waste extract
Industry: electrolytic cell solution, fermentation solution, drug decomposition solution
Agriculture: milk, beverages, food extracts, plant extracts
Medicine: Blood/Serum/Plasma, Urine, Tissue Extracts, Extracellular Fluid
In ordinary manual pretreatment, dialysis is rarely used because the operation is very complicated. We need to prepare various equipment such as semi permeable membranes and dialysis tanks, and external pollution is easily introduced during the operation. Moreover, the operation time and waiting time for dialysis are long, and each treatment is time-consuming and laborious. Therefore, other pretreatment methods were commonly used in previous methods.
For example, if we want to sample samples like milk, common preprocessing steps include:
1. Dilution
2. Ultrasonic dissolution
3. Add 3% acetic acid
4. Filtering
5. Pass through C18 solid-phase extraction column
6. Centrifuge
7. Sample injection
And using the Anglo blue dialysis technology, the pretreatment steps are:
1. Dilution
2. Sample injection
Adopting the technique of dilution with English blue and dialysis with English blue:
1. Sample injection
2.... (No further steps required)
-Application of indigo dialysis

Blue dialysis makes it possible to determine some samples that are very difficult to directly detect, for example, the national standard GBT 20188-2006 uses ion chromatography as the detection method for wheat flour bromate. So, how do samples like flour enter ion chromatography testing? By extension, if we want to test samples such as deep-fried dough sticks and noodles, it will be more difficult. Similar to the processing method of milk, these very tricky problems can be solved by ultrasonic crushing, centrifugation, and indigo dialysis.

-The advantages of indigo dialysis

Yinglan dialysis actually integrates the dialysis module into the robot sample processor, with a total dialysis time of only 6 to 10 minutes, a centrifuged sample volume of only 10 mL, a dialysis rate of over 96%, and no need for pre concentration or filtration. More than 90% of manual labor has been saved.
Another valuable feature is that the Yinglan dialysis technology can achieve simultaneous detection and dialysis, meaning that while the previous sample is being tested, the machine is already beginning to dialyze the next sample for injection. From the entire experimental process, it can be seen that the efficiency of the experiment was greatly improved as there was no additional waiting time.
-Implementation method of indigo dialysis
Yinglan dialysis adopts the principle of semi permeable membrane, which blocks biomolecules, long-chain organic compounds and other substances outside the semi permeable membrane, while small molecules, inorganic cations and anions can be enriched by the receiving solution through the semi permeable membrane. After the dialysis process is completed, the entire dialysis unit can be automatically cleaned and moistened, eliminating contamination or interference caused by manual operation. The dialysis unit and robot sample processor are integrated together, enabling automated operation.
1) Dialysis tank rinsing: There is a porous membrane in the dialysis tank, through which only ions of a certain size can pass. The membrane separates the sample from the receiving solution.
2) Dialysis: Open the sample preparation valve. The sample solution continuously passes through the dialysis cell while the receiving liquid remains stationary in a closed circulation channel. In this case, the measured ions will diffuse through the dialysis membrane, driven by the concentration difference on both sides of the membrane. Due to the continuous inflow of the sample solution, the ion concentration in the sample solution and the ion concentration in the receiving solution eventually reach equilibrium, with equal concentrations on both sides. This equilibrium point usually reaches a sufficiently accurate requirement after 10 to 11 minutes.
3) Transfer: After dialysis, a portion of the receiving solution is transferred to the quantitative loop
4) Injection: Once the pure sample is filled with the quantitative ring, the instrument automatically injects the sample and begins chromatographic analysis. Usually, ultrapure water is used as the receiving liquid for anion determination, and dilute nitric acid is used as the receiving liquid for cation determination.
-Application examples of indigo dialysis
The attached figure shows an example of adding standards for measuring bromate in wheat flour using English blue dialysis. The sample was treated with ultrasound, centrifuged, and directly placed in a robot sample processor for analysis. The small molecules that were not removed by dialysis could no longer affect the quantification of bromate ions. This method has been validated and applied in multiple domestic testing institutions.
Separation column: Metrosep A Supp 7-250
Showdown solution: 3.6mM Na2CO3 ultrapure water solution
Flow rate: 0.7ml/min
Injection volume: 100 μ L
3) Dilute with English blue ™
1. The dilution effect of English blue
When the sample concentration is too high, we can dilute the sample and then pass it through an ultrafiltration unit or dialysis unit. In fact, this dilution step can also be completed by Yinglan technology.
On the other hand, for samples with significant changes in measured data, it is also difficult to organize experiments. For example, for a batch of samples, the concentration difference of the tested ions is huge, and the data points may not fall on the standard curve. If human judgment is used to dilute each sample by different multiples, it will face a lot of manual labor and on duty judgment, and the automatic sampler will be useless.
In addition, if dilution is done manually, volumetric flasks are often needed, and it is very difficult to clean them thoroughly. A slight mistake can cause contamination. Many solutions use peristaltic pumps on automatic samplers to achieve dilution, that is, adding a certain amount of solvent to each sample grade; Alternatively, a buffer unit can be added between the automatic sampler and the chromatograph, and the sample and solvent can be separately added to the buffer unit using a peristaltic pump to achieve dilution. The dilution achieved through peristaltic pumps often lacks precision and requires the integration of multiple peristaltic pumps into an automatic sampler for separate control. The pipeline is complex and difficult to clean, thus limiting its application range.
The dilution of English blue adopts a different method, and the addition process of English blue dilution is not completed through a peristaltic pump, but through a specialized Dosino addition unit. The Dosino dosing unit can be seen as a fixed, multi-channel, continuous flow, and cross contamination free precision mixer, with an accuracy of up to one ten thousandth of the pipetting volume. It is with the help of Dosino that the dilution process is more accurate and error free.
2. Operation process of dilution with English blue:
1) Dosino dosing unit adds the sample and solvent in proportion to the English blue dilution unit
2) The English blue dilution unit thoroughly stirs and mixes the sample and solvent
3) Injection measurement
4) Perform logical judgment while measuring, determine the ideal dilution multiple based on whether the signal falls within the range of the standard curve, and automatically determine whether to perform secondary dilution or injection measurement
5) Automatic emptying and cleaning of the English blue dilution unit

3. Application examples of English blue dilution
Detection of desulfurization wastewater diluted with indigo blue
Rinsing solution: NaHCO3/Na2CO3: 1.0/3.2 mM

Automatic dilution 100 times detection, 20 μ l injection

1 Cl- 1896 ppm

2 NO3- 362 ppm
3 SO42 - 1341 ppm
4) Blue matrix elimination ™
In daily ion analysis experiments, the common matrix (or solvent) is water, which is easy to handle for general ion chromatography. However, for certain special cases, it is necessary to detect the content of inorganic ions in the organic phase, such as inorganic ions in gasoline. At this point, the sample needs to be processed accordingly to remove the matrix, otherwise the matrix will cause damage to components such as chromatography columns and pipelines; The interference of the matrix often prevents the required ions from peaking properly.
The common manual matrix elimination technique is to manually extract and then treat it with a C18 column. Through the adsorption of the matrix by the C18 column, some organic matter is removed. However, this method is difficult to automate and has a small processing capacity; On the other hand, the regeneration of C18 columns is very difficult, and the general matrix has strong adsorption force on C18 columns, making it difficult to wash off completely. Sometimes, in order to regenerate a C18 column, chloroform is added to the eluent. Although it can be washed off immediately, the C18 column can also be quickly damaged as a result. For users who frequently measure ions in organic matrices, traditional methods are undoubtedly a time-consuming and expensive choice.
The Yinglan matrix elimination technology integrates the function of matrix elimination into software controlled automation equipment, enabling the entire process of matrix elimination to be automated. On the other hand, the matrix elimination column can be repeatedly washed and used, greatly reducing the cost of experimental consumption.
1. Steps for eliminating the English blue matrix:
1) The sample is transferred from the robot sample processor to the matrix elimination column, and all the tested ions are retained on the column, while the matrix part is not retained and directly enters the waste liquid pool
2) Transfer the matrix to eliminate the test ions on the column and rinse them off, then transfer them to the quantitative injection ring for analysis
3) The robot sample processor starts processing the next sample
2. Matrix elimination column
Matrix elimination columns are divided into anion specific and cation specific based on the retention of ions, and are designed for different injection volumes. Commonly used matrix elimination columns include:
1) Metrosep A PCC 1 (anionic)/Metrosep C PCC 1 (cationic)
The small dead volume ensures a beautiful peak shape
2) Metrosep A PCC 1 HC (anionic)/Metrosep C PCC 1 HC (cationic)
High capacity version, mainly used for experiments with large injection volume and low ion content
3) In addition, there is a VHC (Very High Capacity) high-capacity version available
Used for pre concentrated samples with high ion concentration in the matrix, such as anion analysis in tap water, anion analysis in Bayer liquid, etc.
3. Example of Eliminating English Blue Matrix
Anion detection in organic solvents (light oil)
As shown in the figure, the blue image is the spectrum without eliminating the sample through the matrix. Due to the interference of the matrix, F -, Cl -, and Ac - are all masked, and other ion detection errors are also significant.
The red graph shows the spectrum after matrix elimination, with a stable baseline and accurate peaks for each ion. It can be fully automated for continuous injection analysis.
5) Neutralization of English blue matrix ™
In many cases, the collected samples have differences in pH, which requires the tester to spend a lot of time adjusting their pH value to the standard state. It is difficult to complete the tedious and tedious task of adjusting pH value in a short period of time in routine experiments. And when it comes to measuring ions in matrices such as caustic soda, ammonia water, boric acid, etc., this problem arises.
1. The purpose of neutralization in English blue matrix:
The English blue matrix neutralization technology is an online neutralization treatment technique. Due to the use of ion exchange to neutralize the substrate, the parallelism of the experiment can be well guaranteed. Even if the substrate is strong acid or strong alkali, continuous direct injection analysis can be achieved using a robotic sample processor.
2. Construction of neutralization module in English blue matrix
The English blue matrix neutralization module consists of three parallel neutralization chambers. When processing acidic matrix samples, the neutralization chamber contains saturated Li+or Na+, which can exchange H+in the matrix for Li+or Na+to increase the pH of the sample. When processing alkaline matrix samples, the neutralization chamber contains saturated H+, which neutralizes with OH in the matrix and generates H2O to reduce the pH.
The purpose of using three parallel neutralization chambers is to have them work alternately, with one neutralization chamber rotating for each sample processed. During the neutralization process of the matrix, one of the three neutralization chambers is in operation, the second is in regeneration, and the third is in flushing to ensure the continuity of the neutralization chamber capacity and sample processing; The regenerated liquids in the neutralization chamber are LiOH/NaOH and HClO4, respectively.
3. Application examples of neutralization in English blue matrix
Measure anions in 30% NaOH solution
As shown in the figure, the blue image is the spectrum of direct injection without neutralization in the matrix. Due to the interference of high concentration NaOH, except for a large negative peak, almost all useful signals are masked.
The red graph shows the spectrum of the sample after neutralization in the English blue matrix. The baseline is stable, and all ions can accurately peak, and it can be fully automated for continuous injection analysis.
6) English blue extraction ™
In many cases, when measuring a large amount of non-polar matrix or trace inorganic ion matrix in high load non-polar matrix, liquid-liquid extraction pretreatment methods such as heavy oil, biodiesel, etc. can be considered. In practical use, the indigo extraction module is often added before indigo dialysis to effectively increase the ion concentration entering the dialysis tank.
1. Working method of English blue extraction
1) Accurately transfer the sample from the robotic sample processor to the extraction tank using the Dosino pipetting unit, while transferring the extraction solution from the fixed container to the extraction tank.
2) The stirring rotor in the extraction tank thoroughly mixes the sample and extraction solution and allows them to separate into layers at rest. The extraction time can be determined by MagIC Net ™ Magician software control.
3) Transfer the extracted inorganic phase to the indigo dialysis unit
4) Analysis of samples after dialysis
5) At the same time of analysis, the indigo extraction and indigo dialysis modules begin processing the next sample
2. Example of the combination of indigo extraction and indigo dialysis
Detection of alkali metals and alkaline earth metals in biodiesel
Extraction solution: dilute nitric acid
Analysis method: Direct injection analysis after treatment with indigo extraction and indigo dialysis module
Separation column: C2 150， Rinsing solution: 2 mM HNO3+10% acetone, flow rate 1.0 mL/min
7) Pre concentration of English blue ™
The direct detection lower limit of ion chromatography is usually in the low ppb range (0.1 ppb~10 ppb), and the pre concentration technology of indigo blue makes it possible to detect even lower ion concentrations! Before entering the chromatographic column from the robot sample processor, the tested ions are enriched through a pre concentration column. By controlling the sample volume or enrichment time, the degree of concentration can be accurately controlled, greatly expanding the application scope of ion chromatography. Compared with large volume injection, pre concentration of English blue can effectively avoid the interference of huge injection peaks and obtain excellent peak shapes and analysis results. Compared to large volume injection techniques, the use of English blue pre concentration technology can effectively reduce the injection volume, protect the chromatographic column, and extend the service life of the chromatographic column.
At present, the pre concentration technology of Yinglan has been widely used for quality monitoring of ultrapure water, and the detection limit of anions and cations can reach ppt level. Many components of the Yinglan pre concentration module can be shared with the Yinglan matrix elimination module, so when combined with Yinglan matrix elimination technology, trace ions in various complex matrices can also be analyzed, such as ethanolamine, morpholine, ammonia water, etc. Anion detection in matrices can also reach ppt level.
Example of pre concentration of English blue:
Detection of Anions in Pressure Water Supply of Nuclear Reactors
35ml sample, After treatment with 0.4 ppm ammonia solution/6.0 ppm ETA, the sample was placed on a robot sample processor and analyzed by injection into a pre concentration unit using English blue. The eluent was 3.6 mM Na2CO3.
(Unit: ppb）
1 F 0.33
2 Ethanol acid 2.23
3 Acetic acid 1.64
4 formic acid 6.47
5 Cl 0.66
6 NO3 0.02
7 PO4 0.08
8 SO4 0.51
8) English blue correction ™
The English blue calibration technique utilizes the principle of English blue pre concentration. When measuring unknown samples with ultra-low concentrations, it is often necessary to use English blue pre concentration technology. However, it is very difficult to prepare such low concentration standard solutions. In fact, it is almost impossible to prepare PPT level standard solutions. In this case, a higher concentration standard solution can be prepared and injected into the pre concentration column. By controlling the injection volume, the ion concentration in the pre concentration column can reach the same level as that of the pre concentration dilute solution, thus eliminating the need to prepare a lower concentration standard solution.
In this way, simply prepare a standard solution of a certain concentration and inject it into the pre concentration column at 1, 2, or multiple times its volume for detection, to obtain multiple corresponding calibration points. Due to the absence of any manual liquid preparation process, the possibility of contamination can be almost avoided. In the experiment of measuring trace ions at the PPT level, the production of standard curves has also been automated.
9) Blue cation elimination ™
When the cation concentration in the sample is too high or there is interference from transition metals (such as in electroplating solution samples), the blue cation elimination technique can be used to replace it with H+ions or Li+ions online (to avoid acidification of the sample). When the cation pairs with weak acid ions, it is particularly important to use the indigo technique for treatment.
10) English Blue Label ™
For the detection of trace substances, the traditional manual labeling method can easily contaminate the sample and greatly reduce the analysis results. Similarly, for non-aqueous matrices such as gasoline, diesel, heavy oil, etc., it is particularly difficult to add standards due to the inability of standard samples to be effectively miscible. Therefore, the English blue labeling technology is mainly used in combination with English blue pre concentration (to detect trace ions, the standard concentration is very low and easy to contaminate), or in combination with English blue matrix elimination technology (organic phase is difficult to label).
The implementation method of English blue labeling is to quantify the sample and standard separately, and then enter the pre concentration column or matrix elimination column in order and be retained. They are both eluted by the eluent and then enter the analysis system. The entire process avoids manual labeling and mixing, achieving very ideal parallel performance.
Taking the detection of anions in gasoline as an example, the use of indigo matrix elimination technology is required, and ordinary NaCl standard samples are insoluble in gasoline. There are reports that use the principle of NaCl slightly soluble in ethanol to produce ethanol NaCl standard samples for analysis, or use TBA salt ethanol solution for addition. However, the actual effect is not ideal. Due to the large variation of NaCl solubility in ethanol with external factors such as temperature, it brings about significant instability. In addition, due to the inability to guarantee the uniform distribution of ethanol NaCl in gasoline, the peak of the standard sample often appears deformed, tailing, and other situations, and the recovery rate is not ideal.
By using the technique of eliminating the English blue matrix and adding English blue standards, it is possible to directly add inorganic anions to gasoline samples as standard samples, with symmetrical peak shapes and high recovery rates, resulting in satisfactory results.