In recent years, photoelectrochemical sensors have become a hot research. To be the key of photoelectrochemical sensor, photosensitive materials play a decisive role in the sensitivity, selectivity and stability of the sensors. In this paper, the principle and classification of photoelectrochemical sensors were briefly introduced. The preparation methods and applications of photoelectric materials commonly used in photoelectrochemical sensors for transition metal oxides and their complexes were described. The development prospects of photoelectrochemical sensors and photoelectrochemical materials were also prospected (67 ref. cited).

A review on the application of laser induced breakdown spectroscopy (LIBS) to the analysis to steel slag during the recent years, including the following five aspects:research progress at home and abroad, system parameter optimization, spectral data preprocessing, quantitative analysis methods, and classification and identification of steel slag, was given. And a brief prospect of future progress of LIBS technology in the rapid detection of steel slag was proposed (52 ref. cited).

An overview on current research progress of the inspection of combustion residues in fire debris from the aspects of the inspection methods of combustion residues, matrix interference and data interpretation, focusing on the research achievements of the inspection methods and chemometric methods were common in this field. Prospects for development in this field were also discussed (56 ref. cited)

Aptamer exhibits unique technical advantage in the aspects of specific recognition on target and signal transduction. Combing aptamer and molecular imprinted technology, the obtained aptamer functionalized molecular imprinted polymer exhibits excellent capability of selective recognition and sensing performance. Based on this, the preparation methods of aptamer functionalized molecularly imprinted polymer were introduced, and their applications in biosensor, separation and enrichment were reviewed and prospected (73 ref. cited).

Surface enhanced Raman spectroscopy (SERS) is a powerful food inspection technology. When the sample is adsorbed on the surface of metal structure with nanometer roughness, the Raman signal of the sample molecule will be greatly enhanced.The detection technology has the characteristics of high sensitivity, rapid response and "fingerprint" identification, and has great application prospects in the rapid detection of food contaminants. In this paper, the development history, basic principle, basement classification and combined technology of SERS are introduced. The latest applications of SERS in heavy metal ions, veterinary drug residues, pesticide residues, illegal additives, food-borne pathogenic microorganisms and other aspects are summarized.Furthermore, the urgent problems and development trends are put forward (74 ref. cited).

A review on the analytical methods for Cr(Ⅵ) in the years from 2001 to 2016 was presented, including spectrophotometry, inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS) and ion chromatography (IC). Prospects for development of the analytical methods for Cr(Ⅵ) were also given (36 ref. cited).

Based on the hair physiology and hairdressing theory, a series of hairdressing process was sorted out, and the influence of hairdressing on drugs analysis in hair from two aspects of external pollution and internal loss was concluded and summarized (45 ref. cited).

Research process of the preparation techniques (i.e., glass fusing method, powder pressing method, powder pressing method, pressing-sintering method, natural mineral picking method, synthetic crystal preparing method and other preparation methods) of reference materials for in-situ micro-area analysis were reviewed, the advantages and disadvantages of each method were analyzed, their related application fields were introduced, especially in deep space exploration, and the application prospects of preparation techniques of ceramic in preparation of reference materials of micro-area analysis were made (53 references cited).

A review on the recent advances of researches on methods (including AAS, ICP-AES, ICP-MS, complex spectrophotometry,catalytic kinetic spectrophotometry and so on) for determination of trace iron in water was presented (48 ref. cited).

A review on advances of application of electroanalytical chemistry in detection of organic synthetic pigments in food in recent years was presented. The advantages and disadvantages of metal nanomaterials, metal oxide materials, carbon materials (including graphene, carbon nanotubes and so on), polymer materials and so on in application of electroanalytical chemistry were discussed specially. Future application of electroanalytical chemistry was briefly given (73 ref. cited).

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A review on methods in common use for determination of hydrogen sulfide gas with their principles (including iodometric titration, methylene blue spectrophotometry, mercurimetric titration, electrochemical method, gas chromatography and absorption-spectrometry) and on the research and recent developments of sensors for H₂S-gas (including metal oxideadsorption sensors, electrochemical sensors and optical sensors) was given in this paper. Virtues and defects, as well as limitations of various kinds of the H₂S-sensors were evaluated, and prospects on the future developments in this field were also given (55 ref. cited).

With the implementation of the guiding principles of The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Q3D elemental impurities and China's accession to ICH, ICH Q3D was implemented in January 2020 in China, and elemental impurities in drugs had gradually become the focus of attention. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) were two methods for the determination of elemental impurities, which were recommended by USP〈233〉, and became alternative methods for the determination of multi-elemental impurities. Element impurities required in ICH Q3D and their sources were summarized, the main advantages, limitations and sample preparation methods for the two methods were summarized, the applications reported in the literature in recent years for active pharmaceutical ingredients (API), raw materials and drugs were covered, and the interference in the process of analyzing drugs by ICP-AES and ICP-MS were discussed. At present, it was a trend to to determine the elemental impurities in drugs by ICP-AES and ICP-MS. The review (75 ref. cited) could provide some references for the development of such methods for the determination of elemental impurities.

Bacillus cereus gyrB gene was used as the target gene, and the specific primers were designed. The reaction procedure was as follows: predenaturation at 95℃ for 5 min, denaturation at 95 ℃ for 15 s, refolding at 50 ℃ for 30 s, extension at 72 ℃ for 30 s, 45 cycles of reaction. Bacillus cereus DNA was used as the template, and a rapid method for detection of Bacillus cereus in food was proposed by fluorescence quantitative polymerase chain reaction (PCR). Tests for specificity of the method, sensitivity of Bacillus cereus DNA and detection limit of live bacteria were carried out. As shown by the results, the primer could achieve rapid detection of Bacillus cereus in segmented amplification, and had good repeatability. 3 non-Bacillus cereus and Bacillus cereus were used for specificity test, and no amplification curve was found for non-Bacillus cereus, but the specific curve was found for Bacillus cereus. Sensitivity detection was performed for Bacillus cereus DNA in 10-fold serial dilutions, giving the result of 0.01 mg·L^-1, and detection limit of live bacteria was 8.9×10²CFU·mL^-1.

A review on research adavances of chromatographic analytical methods of BTEX in the recent years was presented, especially focusing on the introductions of gas chromatography-internal standard method, and pretreatment methods, such as headspace, solid phase microextraction, liquid-liquid microextraction, et al. In addition, the development direction of analytical methods and the control of BTEX were prospected (49 ref. cited).

An aliquot (1.00 mL) of human urine sample was taken, 10 μL of 1.0 mg·L^-1 mixed internal standard solution (containing ¹³C-erythromycin-d₃ and amoxicillin-d₄) and 0.30 mL of Na₂EDTA-Mcllvaine buffer solution (pH 3.5±0.05) were added. The mixed solution was vortexed for 30 s and centrifuged for 5 min. The supernatant was passed through Oasis HLB solid phase extraction column at flow rate of 1.0 mL·min^-1. The column was drained, and eluted by 3 mL of methanol at flow rate of 1.0 mL·min^-1. The eluate was collected, blown to near dryness by nitrogen, and diluted to 0.5 mL by 10% (volume fraction) methanol solution. The resulting solution was vortexed and passed through a 0.22 μm organic filter membrane, after which the filtrate was analyzed by ultra-high performance liquid chromatograph-tandem mass spectrometer. Forty antibiotics (8 sulfonamides, 6 macrolides, 8 β-lactams, 4 tetracyclines, 9 quinolones, 3 chloramphenicols, 1 lincosamide and 1 quinoxaline antibiotics) were separated by gradient elution with mixed solutions composed of 0.1% formic acid (volume fraction, the same below) solution and acetonitrile solution containing 0.1% formic acid at different volume ratios on Kinetex^® F5 100A column (50 mm×3.0 mm, 2.6 μm), ionized by negative (3 chloramphenicol antibiotics) and positive ion mode of electrospray ion source, and detected by MRM mode. Erythromycin and amoxicillin were quantified by internal standard and matrix matching method, and other antibiotics were quantified by matrix matching method. As shown by the results, linear ranges of working curves of erythromycin and penicillin V were 1.0-100.0 μg·L^-1, and linear ranges of working curves of the remaining 38 antibiotics were 1.0-200.0 μg·L^-1, with detection limits (3S/N) in the range of 0.01-1.25 μg·L^-1. Test for recovery was made by standard addition method, giving recoveries in the range of 51.0%-128%, and RSDs (n=5) of the determined values ranged from 1.2% to 14%. The proposed method was applied to the analysis of 10 adult urine samples, and 9 antibiotics were detected in 9 samples, with detection amounts in the range of 0.09-322.86 μg·L^-1, of which the detection rate of amoxicillin was as high as 50% and the detection amount of that reached up to 322.86 μg·L^-1.

The progress on the determination of chlorophenols in water by spectrophotometry, chromatography, mass spectrometry and capillary electrophoresis in recent years was reviewed, and the determination methods of chlorophenols in water were prospected (50 ref. cited).

Food safety problems seriously affect human health, so it is necessary to develop efficient, convenient, and fast food safety detection methods. Metal-organic framework materials (MOFs) are new porous complexes with uniform pore size, adjustable particle size, high specific surface area, and good thermal stability, which can be synthesized according to requirements and have been widely used in food safety detection. Composite materials prepared assembly by MOFs and other functional materials (ionic liquids, quantum dots, graphene, magnetic nanoparticles, gold or silver nanoparticles, etc), making MOFs had advantages based on the original material with other excellent performances including conductive, light, magnetic, catalytic. It has attracted a lot of attention in sensing detection and sample pretreatment. The application progress of MOFs and their composites as sample pretreatment materials or sensing materials in the field of food safety detection were systematically reviewed, such as agricultural and veterinary drug residues, illegal additives, heavy metal ions, organic polutants, and microbial toxins, and its development fulture was prospected (56 ref. cited).

The working principle of analysis technology of hydride generation-inductively coupled plasma atomic emission spectrometry, the reaction modes of hydride generation (acid mode and alkaline mode), hydride generation units (intermittent hydride generation units, continuous hydride generation units and self-made modification units) and the application of the technology in environmental analysis, food and drug analysis, geological analysis and other analysis, as well as the interference and elimination in hydride generation injection technology were reviewed. Meanwhile, the research progress of the technology in simultaneous determination of hydrogenated and non hydrogenated elements was briefly described, and the future development of the technology was prospected (91 ref. cited).

The molecularly imprinted polymer could specifically enrich the target compounds from the sample solution, which had been widely used in the extraction and detection of pesticides in food including cereals, fruits and vegetables, and in the environment including water and soil. The molecularly imprinted fluorescent probe formed by combining molecular imprinting technology and quantum dot modification technology could achieve high-sensitivity and rapid detection of the target compounds. Therefore, the principle, preparation method and application of molecular imprinting technology were summarized, and the application and prospect of quantum dot-modified molecularly imprinted fluorescent probe in pesticide detection were further elaborated.

A review on research progress on extraction methods, separation methods (including GC, HPLC, CE and so on) and detection methods (including AAS, AES, AFS, ICP-MS and so on) for arsenic species (including inorganic arsenic, methylarsenic, arsenical betaine, arsenicone, arsenic sugar and arsenic grease) in aquatic organisms was presented. A brief prospect was also given (74 ref. cited).

A method was proposed for simultaneous determination of 13 α-hydroxy acids in cosmetics by ultra-high performance liquid chromatography triple quadrupole mass spectrometry (UHPLC-MS/MS). The sample(0.2 g) was extracted for 30 min in water by ultrasonic, while the undispersed samples added isopropanol firstly. After centrifuging and filtering, the extracted solution was analyzed by UHPLC-MS/MS. The saparation of 13 target compounds was performed on a Agilent Zorbax RRHD SB-Aq C₁₈ column, using mixtures of 0.1% (volume fraction) formic acid solution and acetonitrile at different volume ratios as mobile phases for gradient elution. Electrospray ion (ESI) source with multiple reaction monitoring (MRM) mode in the negative ion mode were adopted in MS analysis. As shown by the results, linear relationships between values of peak area and mass concentration of 13 α-hydroxy acids were found in definite ranges, with detection limits (3S/N) of 0.030 μg·g^-1 for hydroxycaprylic acid, benzilic acid, and α-hydroxy-decanoic acid, 3.0 μg·g^-1 for glycolic acid and lactic acid, and 0.30 μg·g^-1 for the other 8 α-hydroxy acids. Test for recovery was made by standard addition method, giving results in the range of 85.1%-114%, with RSDs (n=6) of the determined values less than 10%. This method was applied to the analysis of 20 samples, with the total amounts of α-hydroxy acids in the range of 20-6 800 mg/100 g, which were all in standard permission scope except an exceeding sample.

Water was added in the sample of Scutellaria baicalensis extract. The mixture was extracted twice with methanol ultrasonically. after centrifugation, the combined supernatant was made up to 50.0 mL with water. The solution was filtered on 0.22 μm microporous membrane. UHPLC-MS/MS was applied to the simultaneous determination of 4 flavonoids, i.e. baicalein,baicalin,oroxindin and scutellarin in the filtrate. ACQUITY UPLC HSS T3 chromatographic column was used as stationary phase, and the mixture of 0.01% (mass fraction) ammonia and acetonitrile mixed in different ratios was used as mobile phase in gradient elution. ESI^- and multi-reactions monitor mode were adopted in MS/MS. Linear relationships between response values of mass spectrometry and mass concentration of the 4 flavonoids were kept in the same range of 5.0-500.0 μg·L^-1, with detection limits (3S/N) in the range of 0.3-1.5 μg·kg^-1 and lower limits of determination (10S/N) in the range of 1.0-5.0 μg·kg^-1. On the base of blank sample of Scutellaria baicalensis extract, test for recovery was made by standard addition method; values of recovery found were in the range of 91.1%- 99.1%, with RSDs (n=6) of determined values in the range of 2.0%-4.1%.

A review on the research progress of determination methods(including spectrometry, electrochemical methods, chromatography, biological methods, chemical methods and other methods) of formaldehyde was presented. Prospects on the trends of development in this field were also given (55 ref. cited).

A method for the determination of nicotine in tobacco by high performance liquid chromatography (HPLC) was developed. Tobacco sample powder of 0.5 g was dissolved in 75% methanol solution containing 0.1 mol·L^-1 sodium hydroxide and made its volume up to 100 mL. After ultrasonic extraction for 30 min, HPLC was used for determination. As shown by the results, linear relationship between mass concentration of nicotine and its peak area was kept in the range of 3.00-100 mg·L^-1, with detection limit (3S/N) of 0.5 mg·L^-1. RSDs of intraday (n=6) and interday (n=9) were 0.47%-1.1% and 0.44%-0.97%, respectively. Recovery test was made on tobacco sample at 3 concentration levels by standard addition method, giving results in the range of 97.4%-100%. This method was used to analyze the actual samples and compared with gas chromatography (YC/T 246-2008) and spectrophotometry (GB/T 23225-2008), with the determined values by this method basically consistent with those of spectrophotometry, and RSDs of the determined values by the proposed method were less.

A review on recent progress of research on methods for determination of total tin in geological samples (including volumetry, spectrophotometry, hydride generation atomic fluorescence spectrometry, atomic absorption spectrometry, polarography, atomic emission spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry and X-ray fluorescence spectrometry) was presented (70 ref. cited).

The principle, characteristics and commonly used chemiluminescence systems of flow injection-chemiluminescence were briefly introduced, and the application progress in the pharmaceutical (induding vitamin drugs, antibiotics drugs, hormone drugs, antitumor drugs, traditional Chinese medicine and other drugs) analysis in recent 20 years were reviwed. Some suggestions were proposed on the problems existing in the flow injection-chemiluminescence, and application prospect of the method was prospected (136 ref. cited).

The content control of heavy metal and other elements had always been a problem that needed attention in the production process of drug, and it was also an important issue of drug safety. Inductively coupled plasma mass spectrometry (ICP-MS) was used for element analysis, the operation was relatively simple, and it had the advantages of low detection limit, wide linear range, simultaneous determination of multiple elements, fast analysis, high accuracy, and good sensitivity. After China joined the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), the control of element limits in drugs was also be in line with international standards, so it was especially important to adopt effective detection methods. Research progress of determination of heavy metal and other elements in Chinese crude drug, Chinese patent medicines, and chemical medicines in recent years by ICP-MS was reviewed. The source control and sample pretreatment methods of heavy metal and other elements in drugs were introduced, and the development of ICP-MS in this field was prospected (51 ref. cited).

The application of point-of-care testing (PoCT) methods meets the demand for fast, accurate, and simple detection in food, quarantine, clinical and other aspects. Carbon dots (CDs) as a novel nanomaterial, has been widely applied in various PoCT methods due to easy preparation, small particle size, good biocompatibility and low toxicity. Therefore, the preparation and characterization methods of CDs were introduced, and the applications of CDs in PoCT methods were reviewed from the perspectives of food safety, quarantine, and clinical testing. The development of PoCT methods based on CDs was prospected (95 ref. cited).

The shredded textile sample (0.500 0 g) was extracted ultrasonically at 60 ℃ for 30 min with 30 mL of methanol. After cooling to room temperature,the supernatant was taken and filtered with 0.45 μ m organic filter membrane. HPLC was applied to the simultaneous determination of 11 benzophenone-type ultraviolet absorbents in the filtrate. xBridge shield RP C₁₈ chromatographic column (250 mm×4.6 mm, 5 μm) was used as separation column, and mixtures of 0.1% (φ, the same below) formic acid solution and methanol-isopropanol solution (volume ratio of 7∶3) containing 0.1% formic acid with different mixing ratios were used as mobile phase in the gradient elution. Detection at 280 nm was adopted in the determination. Linear relationships between values of peak area and mass concentration of the 11 benzophenone-type ultraviolet absorbents were kept in the same range of 0.5-20.0 mg·L^-1, with detection limits (3S/N) in the range of 3-9 mg·kg^-1 and lower limits of determination (10S/N) in the range of 9-27 mg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 87.6%-107%, with RSDs (n=6) of determined values in the range of 1.9%-8.3%. The method was used to analyze samples of 33 batches of anti-ultraviolet fabric. Except that 4-hydroxybenzophenone was not detected in all fabrics, other benzophenone-type ultraviolet absorbents were found in these samples. The highest detection rate of 2-hydroxy-4-methoxybenzophenone was 58%, and the mass fraction of 2-hydroxy-4-methoxybenzophenone was in the range of 42-261 mg·kg^-1.

A method for screening of 150 drugs and toxic compounds in urine by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS^E) was proposed. Urine samples were prepared by liquid liquid extraction, then separated on ACQUITY UPLC HSS C₁₈ column, with mixtures of acetonitrile solution containing 0.1% (volume fraction) formic acid and 5 mmol·L^-1 ammonium formate solution (pH 3.0) at different volume ratios as the mobile phase for gradient elution. The positive ion mode of electric spray ionization was applied and full scan mode was used for screening. 150 compounds were identified according to their retention time and the information of parent ions and fragment ions. As shown by the results, there were 13 isomers in 150 compounds, and 10 out of 13 isomers could be successfully distinguished from each other based on different retention time or unique fragment ions. The detection limits (3S/N) for 150 compounds in urine were in the range of 0.2-25.0 μg·L^-1. The absolute matrix effects for 68 representative compounds ranged from 23.1% to 119%, and the extraction recoveries ranged from 30.8% to 115%. This method was used for screening analysis of 120 actual urine cases, and 10 samples were positive.

HPLC was applied to the determination of tranexamic acid in whitening freckle cosmetics. The sample (0.500 0 g) was extracted ultrasonically with 20 mL of mixture of saturated sodium chloride solution and methanol (1+1) for 5 min. After centrifugation,the supernatant was evaporated to near dryness by N₂-blowing at 45℃ in a water bath. 1 g·L^-1 dansyl chloride solution (500 μL) and 100 mmol·L^-1 NaHCO₃ solution (500 μL) were added to bring derivatization reaction for 5 min. After cooling, the solution was filtered on 0.22 μm microporous membrane. Zorbax SB C₁₈ chromatographic column was used as stationary phase, and the mixed solution of acetonitrile and 0.1% (φ) formic acid solution mixed in different ratios was used as mobile phase in gradient elution. Detection at 250 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of tranexamic acid was kept in the range of 1.0-100.0 mg·L^-1, with detection limit (3S/N) of 0.3 mg·kg^-1. The proposed method was applied to the analysis of samples of whitening freckle cosmetics, giving values of recovery and RSDs (n=6) in the ranges of 90.8%-98.0% and 2.0%-2.8% respectively.

New drug crime had become a prominent issue of global public security. As a new type of drugs, it was becoming a serious problem in manufacturing, smuggling and abuse of fentanyl compounds all over the world. Based on this, the types and structure characteristics, metabolism and toxicity in vivo, pretreatment methods and determination methods of fentanyl compounds were reviewed, and a prospect was given about the development trend of its determination methods in future (34 ref. cited).

A review on development of dispersive liquid-liquid microextraction based on solidification of floating organic droplet, and its recent progress of application in sample analysis of water, food and biology was given in this paper. A brief prospect was also given (67 ref. cited).

Detecion techniques for organic explosives normally used by both laboratory and on-site in forensics were concluded. The techniques were classified as chromatography (gas chromatography and liquid chromatography), mass spectrometry (ambient ionization mass spectrometry and isotope ratio mass spectrometry), chromatography-mass spectrometry combined technology (liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry), capillary electrophoresis, ion mobility spectroscopy, spectroscopy (infrared spectroscopy, Raman spectroscopy and terahertz), and sensor technology (fluorescent sensor, electrochemical sensor and surface plasmon resonance sensor). Additionally, the development direction for future detection technique of organic explosive was discussed (61 referencens cited).